Thermos Testing

I’ve known for a long time that my Stanley bottle didn’t hold heat nearly as well as my Thermos Nissan.  But just how bad it was became apparent to me as I made yogurt the other day.

Comparative testing of the heat retention of a Stanley, Thermos Nissan and glass-lined Thermos bottle.

Dave had an early appointment and I’d sent him off with the good Thermos Nissan bottle (center) full of coffee.  Then I realized that I needed to make yogurt.  No problem, I’d use the Stanley (on the left).  Well, the yogurt that normally takes 5 hours to culture in the Thermos Nissan still wasn’t 100% done after 11 hours in the Stanley — but it was no longer warm.

So I played “test lab” a bit and added in the glass-lined Thermos that I have.  The three bottles, as pictured from left to right, are:

All hold between 3 and 4 cups of liquid.  I set all three in the sink, then boiled a big pan of water to a full rolling boil (Dave wondered what in the world I was doing as the steam billowed . . .).  I filled all three bottles to their fill line, then quickly stoppered them.

I let them sit about 10 minutes as I boiled another big pot of water, so as to pre-heat each of the bottles.  When the new water was boiling, I poured the old water out quickly, then refilled each bottle with fresh boiling water and stoppered the bottles.  I placed them all on the same counter, about a foot from each other so that none were getting warmth from another.

I let them all sit for 5 hours — the length of time you might want to keep coffee hot, or make yogurt, or for Thermos cooking.  I took the lid off each in turn, then used an instant read thermometer to check the water temperature inside.  Maybe not quite as rigorous as Consumer Reports, but better than just a “gut feeling” that one does better than another.

If you’ve ever wondered if the Thermos Nissan bottles are worth the extra money — or if the Stanley bottles could really be that bad — the answers seem clear:

The Stanley bottle fared by far the worst, with the water at just Comparative testing of the heat retention of a Stanley, Thermos Nissan and glass-lined Thermos bottle.94 degrees F. — a drop of 118 degrees. Well, that explained the yogurt not culturing — it started at 120 degrees and needs to stay between 110 and 120 to culture.  If the temperature dropped to 94 when starting at 212, it had to have dropped to room temperature pretty quickly when it started at 120.

Okay, so now I have a nice stainless bottle that has proven to be pretty useless for its intended purpose . . . maybe I can use it as a vase?  Other ideas?

Comparative testing of the heat retention of a Stanley, Thermos Nissan and glass-lined Thermos bottle.The Thermos Nissan bottle did the best, with the water at 186 degrees F. — a drop of just 26 degrees.  Interestingly, while it holds the most liquid, it has a considerably smaller diameter and is far lighter weight than the others.  The heat retention is fantastic — I just wish they made a wide-mouth bottle that was smaller than 48 ounces (6 cups) — while that’s great for Thermos cooking, it’s too large for making yogurt and so I have to use the narrow mouth bottle, which is a little harder to pour the finished yogurt out of.  But the extra hassle is well worth it, with the consistently great results I get.

UPDATE:  A reader did the same test on her 34-ounce bottle from REI — which looks very similar to the Thermos Nissan bottle — and got almost identical results to the Thermos Nissan bottle (she was using a dial thermometer, making it hard to know the exact temperature).

Comparative testing of the heat retention of a Stanley, Thermos Nissan and glass-lined Thermos bottle.The glass-lined Thermos was the one that surprised me.  No, it wasn’t quite as good as the Thermos Nissan, with the water registering 175 degrees F. — a drop of 37 degrees.  But it was by far the cheapest originally (I think I paid less than $10 for it) and it has an uninsulated stopper called a “Stash Top” where you can store sugar and cream packets.  That had always struck me as a quick way to lose heat!  See a picture of the Stash Top in my original article on Thermos bottles.

Bottom line:

  • Best bottle:  Thermos Nissan (I love mine) or REI one-liter
  • Best economical bottle:  A glass-lined Thermos (but be gentle with it so as not to break the glass — it’s easier than you think on a boat)
  • Don’t buy:  Stanley

If you have any experience — good or bad — with particular bottles, please add a note in the comments.  A good “Thermos” bottle is an important piece of equipment in a galley, so let’s share info on what works and what doesn’t!

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  • Chris
    Posted at 21 July 2011 Reply

    What a great article/test. I appreciate you sharing your findings. I have been contemplating trying to bring hot lunches to work in a Thermos and frankly, with no research, I would have bought the Stanley based on looks and name reputation. I am so glad I found your article.

    • Carolyn Shearlock
      Posted at 21 July 2011 Reply

      Chris —

      That’s exactly how I ended up with the Stanley — I mean, it looks like a heavy duty “Thermos” and tons have been sold . . . so it HAS to be good, right?

      I soon discovered, WRONG.


    • david
      Posted at 10 January 2013 Reply

      I read about someone drilling a hole in the top and bottom of a stanley and filling it with foam. Ever hear of that. He said it worked great.

      • Carolyn Shearlock
        Posted at 11 January 2013 Reply

        I haven’t heard of anyone doing it. That expandable foam can be very messy to work with!

      • vrkelley
        Posted at 14 December 2013 Reply

        >>drilling a hole in the top and bottom of a Stanley and filling it with foam.
        Would you post a link? Need the drill bit size and some sort of temperature reading after X number of hours.

        • Carolyn Shearlock
          Posted at 14 December 2013 Reply

          It’s not something that I know about, and a Google search didn’t bring it up. That expandable foam is just nasty stuff to work with and I can’t imagine getting it in through a small drill hole!

          • Joe
            Posted at 21 December 2013

            I did this just last week. I read it in a blog somewhere, but cannot find it know. One guy tried it and said it worked. Another guy tried it and the next morning the bottom was pushed out because of to much expansion of the foam.
            Now my experience!!
            I followed the directions like this. Drill hole in one side on the bottom. I drilled hole big enough to insert the straw on can. Then I drilled another hole on the other side on top. They stated 1/8 whole. I used the same bit for both holes. Then being the one guy pushed the bottom out of his thermos, I decided to use the “windows and doors” can of foam (blue can) instead of the (red can).
            Well to say I am satisfied with the outcome….. HECK NO!
            First: There was some kind of black stuff in side my thermos, that stuff shot out the top hole, all over the place when I shot the foam in the bottom hole. I spent 2 good hours cleaning the stuff up. My brother did find a link somewhere that some Stanley Thermoses have this stuff in them. From what I read this is more common than Stanley will admit.
            Second: Once I finally was able to shoot more foam in, it kept coming out the top hole. I assumed it was full so I stopped. Now the thermos does not keep anything hot.
            I may buy a can of the great stuff, red can this time and see if things change. This time I will be outside when I do it though. I’ll let you know how or if the red can works.

          • Carolyn Shearlock
            Posted at 21 December 2013

            Thanks for sharing the story — I’m laughing out loud picturing the black goop coming out followed by a string of foam, it’s so like my one experience with a can of foam. It was not good. I swore I’d never go near the stuff again. It expanded everywhere! I got it in the (new) carpet . . . for what it’s worth, it’s REALLY hard to get out of carpet.

            Outside of the entertainment value of playing with this, I’m thinking it’d be a lot easier to just get a good Thermos Nissan. I know, you’re like me — you hate to throw anything out!

          • vrkelley
            Posted at 21 December 2013

            Cry-kee! I had high hopes! The black stuff could be a factor in heat-keeping. I’m trying a few things too. My Wide-mouth 16 oz Thermax “keeps food hot 9hrs”…fails to keep the oatmeal hot. 1. 11PM I pre-heat the thermos with boiling water. 2. While the thermos is heating, I boil another 12 oz of water. 3. I quickly drain the thermos and drop in 1/2 of old fashion oats, 1/3C dry milk and the 12 oz of water (fills the bottle up to that rim mark). 8hrs later the oats are cooked the best ever–luke warm at best –even after wrapping in a thin dishtowel.

          • Carolyn Shearlock
            Posted at 21 December 2013

            Oh no! Not what you need on a cold morning 🙁

  • John Beale
    Posted at 17 November 2011 Reply

    Very nice job on the thermos bottle tests! I appreciate you doing the experiment and writing it up. Unless the bottle is really broken, what I have heard is that almost all the heat lost from a thermos is through the top, so the type of cap used really matters.

    • Carolyn Shearlock
      Posted at 17 November 2011 Reply

      I had thought the same thing, but in testing it was obvious that the bad ones felt hot to the touch all over. The cap on the Thermos Nissan doesn’t “feel” like it’s anything special, and the one on the glass-lined Thermos is obviously hollow to hold cream and sugar packets, yet they both do much better than the Stanley with what feels like the “best” lid . . . obviously not!


  • Marty
    Posted at 10 December 2011 Reply

    I have been suffering with a Stanley for long enough. A few minutes after I fill it with hot coffee (maybe 190 degrees?), it feels hot to the touch on the sides. You know that can’t be good. Although it is tough enough to drive nails with, if it won’t hold temperature, what’s the point. I’m putting the Nissan on my Christmas list.

    • Carolyn Shearlock
      Posted at 10 December 2011 Reply

      Let’s hope Santa is reading this! I love my Thermos Nissan and really wish I’d broken down and bought it a lot sooner!


  • James A.Cormier
    Posted at 13 June 2012 Reply

    I agree the new “Thrmos Bottles” which are now made in China (go figure) are useless compared to the much older ones which where made in CANADA before the company went cheap shipped off the production to the chinese. As with most of the quality of goods they went down hill.

  • Martin
    Posted at 31 October 2012 Reply

    Thanks for the great info, Carolyn. Where I live (SE Asia) I haven’t seen the Thermos Nissan brand for sale and suspect that if I do find it, it will be too expensive here. What they do have for sale here are dozens of mostly stainless steel thermoses of various shapes and sizes, most made in China, some in Thailand. They’re not cheap, either; average price is about $20 or more.

    Since here, unlike in the west, stores don’t let you return stuff for a refund, it would be really helpful if you could tell us exactly what construction features about the Nissan you feel contribute to its excellent performance. If I knew that, I could try to find a thermos that is made the same way.

    Most of the thermoses here seem to have a single layer of metal, fairly thick, that insulates the liquid. Some have two layers separated by some other material, maybe plastic. Some have a button on the stopper that seems to function to let you pour some of the liquid out.

    Some have a stainless coffee maker type basket under the stopper, which I don’t need as I don’t intend to cook coffee in the thermos, just rice and beans, hopefully!

    Anyway, if you could give an opinion about the technical reasons why the Nissan excelled and the Stanley failed, that would be very helpful.

    • Carolyn Shearlock
      Posted at 31 October 2012 Reply

      The basic difference seems to be that the Thermos Nissan bottles DON’T have anything — even air — between the inner and outer layers of stainless. It’s truly a vacuum and thus heat does not transfer.

      Unfortunately, I don’t know how to test or check for that in the store. It would seem that something called an “insulated” bottle wouldn’t be as good, and one called a “vacuum” bottle would be better. Any form of insulation or air will pass heat to some extent.

      The bottles with a single thick layer of stainless seem to me would be the least good; the ones with two layers and some form of insulation better; and if you can find one that’s two layers with a vacuum between them, that’s the best.

      I don’t have any real data to back it up, but my gut feeling is that the buttons, pour mechanisms and so so just add pathways for heat to leak out. A tight fitting cap and some sort of gasket on the stopper seem to help.

      Good luck finding a good one!


  • jude
    Posted at 02 December 2012 Reply

    I just found this post- I had known to stay away from Stanley but thought Thermos was still safe- maybe not. I had a Thermos SS insulated quart bottle for over 25 years and it is still keeping coffee piping hot for 10 hours. Problem is handle broke and I went to Target and bought the highly recommended “The Rock” and was dismayed to find it says “Made in China” and sadly it cant hold a candle to my old one. If I could only put the handle from the new one onto the old one… Oh well nothing is as it was anymore. I am crushed.

    • Chip Lawson
      Posted at 05 December 2012 Reply

      Just an idea. Make a tight-fitting fabric pouch with a webbing handle to hold the old stainless Thermos.The old bottle will be as good as new and if you want you can use some cool looking fabric (US Flag, bright color, wild print) or even a protective/insulating cover like neopreme (wetsuit fabric)

  • Chip Lawson
    Posted at 05 December 2012 Reply


    I am sure you already know it but you have many male followers as well. I find your articles incredibly interesting and valuable. Just bought your book as well to learn more from you. Keep up the GREAT work.

    With respect to vacuum bottles, do you have any experience or thoughts about the performance of the pump top models? I see that Thermos Nissan does not make a pump-top. I have always liked the single-handed convienence of that style when grabbing something hot during a cold night watch but your performance testing makes me wonder. Any thoughts you can share?


    • Carolyn Shearlock
      Posted at 05 December 2012 Reply

      Hi Chip!

      I know that about 40% of the Facebook fans are male and it’s great! While my husband is emphatically not a cook (unless you count microwave popcorn), I know that lots of guys are. I love that TBG is NOT a women-only site!

      Now as to your question — my experience with the pump tops is about 10 years old. It seems that if the bottle itself is a good vacuum insulated (NOT foam insulated), the type of top is less important. For example, my glass-lined vacuum Thermos has a thin plastic top with a space in it for sugar and cream packs. It would seem that it would let all the heat out instantly! But coffee actually does well in it — not as good as in the Thermos Nissan with the good top, but not bad.

      With luck, maybe someone with more recent experience will answer your question!

  • Lilly Kennedy
    Posted at 19 December 2012 Reply

    Do you know when the Thermos Nissan was made? The reviews on Amazon for it are 50-50. I wonder if the product quality is the same as when you bought yours?

  • Carolyn Shearlock
    Posted at 19 December 2012 Reply

    One that I have is about two years old and another is about four months old. Both work very well. A close friend got one about a month ago — the 34-ounce size – and I just talked to her to check and she says it’s great.

  • Jason
    Posted at 25 February 2013 Reply

    Are you sure the vacume seal on the stanley is not damage mine after 10 hours is still at 140 degrees and i had two cups of my hot tea out of it. the have a lifetime warranty you can contact stanley and they should send u a new one

    • Carolyn Shearlock
      Posted at 25 February 2013 Reply

      I suppose that’s possible, but you’re the first person who seems to have one that does retain heat well.

      • Rob Young
        Posted at 26 January 2015 Reply

        Just got a new China made Stanley 1.1st
        while out plowing snow for 13 hous . My last cup was still hot enough to sip. Not warm not boiling. But still hot. I have no complaints so far. I will say I do preheat for at least a half hour to an hour before I fill with coffee though

      • J Z
        Posted at 28 June 2015 Reply

        I just bought two Stanley Utility Food Jars, the cheapest model probably. The instruction claims 6 hours hot and 6 hours cold. I use them to cook whole grain rice and soup. The result is good. I tested them with boiling water too. After 6 hours the temperature is about 160F/70C, 8 hours 150F/60C. It holds heat roughly the same as my Thermos 1.2L sportsman (no sportsman label here Canada, just 24H heat/24H cold). I only have the Stanley for 2 days but so far I am happier with them than the Thermos counterpart GS3000 (500ml), which I returned to CanadianTire the next day because the plastic bottom got loose after one hand-wash.

        BTW, the cap of the 1.2L thermos also got quite warm as the cheaper Stanley.

        • vrkelley
          Posted at 29 June 2015 Reply

          Glad they are working out. Hang on to your receipt in case the seals fail after a few months.

  • Mia
    Posted at 14 May 2013 Reply

    I have just a few cents worth to add to the discussion, my needs for a good thermos relate to school lunches, so not as exciting as the high seas, but there you go. Glass is not a good conductor of heat, but stainless steel is an excellent conductor of heat. The modern manufacturing methods which give us such sturdy thermos’ mean that the design flaw is built-in, as the SS means that the heat can get conducted directly from the internal wall to the external wall. So to compensate well for this the rest of the construction has to be super-efficient, so the vacuum is more important for overall performance. Don’t know if I have written that very well. Cheers, Mia.

  • Stan Cole
    Posted at 22 May 2013 Reply

    I have an all Stainless Can or bottle cover. When I first bought it it worked great for keeping cold beverages that way long enough to enjoy them. but after a while I noticed that it didn’t work (Insulate) any more, outside got cool inside got warm. I contacted the distributor and asked and was told that the vacuum seal had leaked filling the insulating vacuum space with air and perhaps water. so the earlier comments on the Stanley bottle that leaked vacuum might hold true. of course if leaking vacuum is normal then it’s still not worth buying. It’s kind of like the glass vacuum bottles just a lot less obvious when it becomes broken .
    Also have you ever considered filling your “stash top” with pour foam or aerosol foam like “great stuff” or other construction foam

  • Ruth
    Posted at 04 June 2013 Reply

    I just had the opportunity to run a similar test on Buddy products. I compared them to all the travel mugs in the kitchen plus my 2 small thermoses. The starbucks bullet won. Hands down. The buddy products all were sad and HOT on the outside except 2 of them. the 16 oz hero and a smaller version performed way ahead of the group.

  • john
    Posted at 28 July 2013 Reply

    you cant get any better than the old Thermos vacuum bottles made in Batesville. MS (Thermos household international co)
    those suckers will keep coffee hot in below freezing temps for hours, i have been using them for years and have never been disappointed with the way they work.
    My first thermos was glass lined but it was too easy to break but they were still better than stanley because they didnt lose heat as fast(stanley takes about an hour to create a cup of luke warm coffee which is totally unacceptable in sub zero temps)
    great article, keep up the good work.

  • Shaun
    Posted at 17 September 2013 Reply

    Excellent research. Ive been looking for the best “thermos” to store coffee for work. Thanks for the time and effort you put in testing these different products, it is much appreciated.

  • Clay
    Posted at 15 October 2013 Reply

    My old Stanley (~1976) still works great, I got a new(pretty) Stanley and it’s awful.

  • vrkelley
    Posted at 08 November 2013 Reply

    Thank you for your thermos help. I’d llke to add the ZOJIRUSHI thermos specs. This chart shows heat specs after 6hrs.

  • vrkelley
    Posted at 09 November 2013 Reply

    Here is the link…

    Also looking at the types of bottles you tested, the wide mouth thermos loses heat out the top more readily than the narrow one.

  • Charles Agnew
    Posted at 06 December 2013 Reply

    Greetings Carolyn,
    I fully agree with your assessment of the Thermos Nissan vacuum flasks. I have been using the 26 oz. version for some time, and found it to be an excellent product, but wanting something with more capacity I ordered the 34oz. version. I just received it, and have not yet had an opportunity to use it, therefore my issue is not with quality(I’m sure it will perform as admirably as the 26oz. version). My issue is with capacity. On the web-site, the flask I ordered was listed as 34oz.(1L). A litre is 35.2oz. not 34oz., but of more concern to me is that my flask holds less than 31oz., measured to the lip where the stopper seals(the recommended fill level). My question, Carolyn, have you had occasion to measure the capacity of your 340z. flask? Any info. would be greatly appreciated. Thank you, Chas.

  • Sam
    Posted at 13 December 2013 Reply

    I think that it may have to do with the quality of Stanley. They currently are produced in China and Korea, when originally they were made in the USA. I own an old Stanley a-944dh, and it has weight to it, while recently I came across a modern one and it was exceptionally light. The old ones I find to be amazing for heat retention. I have on more than one occasion forgotten it out in my car, only to come back 24 hours after I have filled it to find the contents still very warm. Did I mention its winter and I live in Minnesota? I find that impressive!

  • Doug
    Posted at 28 December 2013 Reply

    I bought a Stanley about 4 years ago 1.1 Quart which kept the contents hot for quite a while. We never checked how long though. However we were constantly going through stoppers. The hot water will turn the stopper into brittle plastic after about 6 months of constant use. Each time I emailed Stanley they told me that the stopper isn’t covered under the lifetime warranty but as a courtesy they would ship one to us.

    Then we decided to purchase a wide mouth Stanley. Big mistake it won’t keep water hot for more that about 3 hours.
    Thanks for doing the comparison we are on our way to find a Nissan Thermos.

  • BeachDude
    Posted at 08 January 2014 Reply

    I too own a Stanley Classic wide mouth 24oz food vacuum bottle, (date code D 10). I could have sworn that it did at one time keep food warm, (the first time I used it my Asturian Bean Stew was hot after 6 hours). However, after that first time it would only keep anything luke warm after only a couple of hours. I was going to go through the trouble of conducting similar comparison testing with an old 32 oz stainless steel vacuum bottle I purchased over 25 years ago at Price Club that still works perfectly. But, I recalled that the most recent time that I used the Stanley and was going to prepare it for use, (when I poured boiling hot water into it), I could feel the warmth on the outside of the bottle within five minutes. The vacuum insulation is gone! I called the Stanley Customer Service 800 number on the bottom of the bottle and a replacement is being sent.

    Apparently, you should not be able to feel the hot or cold on the outside of a working vacuum bottle. If you can, the vacuum has leaked and the bottle will not retain heat or col as intended. While it sounds like common sense, it didn’t immediately occur to me! Many of the latest Stanley brand vacuum bottles for both food and coffee neck sizes, (they also manufacture under the Thermos brand), manufactured in China have a tendency to leak, unlike the old Stanley bottles that work forever. The bottom of the bottle is not always welded as good as they should be, and a simple drop can create a leak. It’s almost as bad as having an old glass thermos!

  • Suzanne
    Posted at 26 January 2014 Reply

    My insulated travel mug recently gave up the ghost. In seeking a replacement I focused on your advice to get vacuum insulated stainless steel. I picked up an 18oz travel mug and 40oz large mouth thermos by Hydro Flask at Eastern Mountain Sports. Both say they are 18/8 stainless and vacuum insulated. Designed in Oregon but… Made in China. Coffee is still steaming after an hour, still drinkable after two, but COLD after 5 hours. I admit I don’t fill the entire thermos with boiling water first, but I do fill it about a third of the way while I let the coffee brew (one full kettle divided between the French press and thermos). There can’t be much space between the walls and the thermos is definitely warm to the touch when I add hot water/coffee. I was really hoping for something that would keep coffee hot for at least 8-10 hours. Lesson learned… Will have to add a couple Thermos Nissan ones to my Amazon cruising wish list!

  • vrkelley
    Posted at 26 January 2014 Reply

    I wouldn’t expect the travel mug to keep coffee hot beyond 2hrs. The 40oz thermos should keep things hot (and I wonder if it; is defective).

  • kumar
    Posted at 26 January 2014 Reply

    The Stanley thermos that perform well is the Aladdin Stanley (vintage) model made in the Nashville, TN. The newer ones do not compare. That is why the vintage ones are hard to find and fetch a high price at ebay. These have performed for 30-50+ years.

  • Nikki Dowden
    Posted at 12 April 2014 Reply

    THERMOS NISSAN JCG300P6 Stainless Steel Food Jar (10-oz) Could this help with the yoghurt? I found it on Amazon uk.

    • The Boat Galley
      Posted at 14 April 2014 Reply

      I love the 10-ounce Thermos Nissan jars for yogurt. They hold the heat SO well.

  • Antony Dalton
    Posted at 13 April 2014 Reply

    I gotta tell ya, I haven’t done any scientific testing, but my Stanley, which looks like a slightly different model than what you have there, keeps my coffee hot ALL day and into the evening. I love it!

    • The Boat Galley
      Posted at 14 April 2014 Reply

      I’ve heard that some of the older ones are MUCH better than the newer ones.

  • The Critic
    Posted at 09 June 2014 Reply

    Hi, everyone,

    I once had an insider relationship with Stanley, and utilizing that, I literally just got off the phone with a higher up (6-9-14) speaking in regards to their failing quality.

    I will preface by stating that despite the fact that there are more important issues to allocate time to, it angers me when consumers are taken advantage of by a company that misrepresents its products via the milking of a prior reputation.

    Here’s the sad truth. In 2010 Stanley stopped putting charcoal into their products as an insulator. This has resulted in an inferior product that they refuse to acknowledge.

    Their reasoning is that they “discovered” that by increasing the thickness of the steel (which he claims they have done) and using a double-wall (empty space)cavity, that it provides a superior product -according to their testing.

    I suggested that he look at the countless complaints all over the internet from real consumers, offering real world testing (at their own expense, by the way!) that all resulted with the same inferior results.

    His reply: “We produce so much product, that a few complaints are insignificant because there’ll always be a few defective ones. Furthermore sales are up 60% this year over last.”

    I pressed further, trying to convince him that this is more than a “few”, and that maybe sales are up because new consumers are unaware of the quality difference. I explained that perhaps these new consumers of their product just simply think that’s the way it’s always been.

    His reply: “Probably.” I’m glad he at least acknowledged some reasonable logic. But next, he attempted to pacify me by resorting to the old insane liberal excuse (yes, I’m saying it’s insane) that “charcoal was bad for the environment -and the consumer if it got out.”

    Wait a minute. So now he’s saying that for 100+ years they thought that the charcoal lining could be breached and be a hazard to the consumer?! Golly, maybe they should’ve stopped with the evil charcoal from the get go, or at least put a warning on their product. I wonder why they didn’t… Oh, that’s right -the bottom line.

    That’s really what this is all about, my friends, the bottom line -and it should be.

    Companies should make a profit, no doubt; however, as I stated previously, not at the expense of an unsuspecting consumer, and not by using old testimonial from their product before their cost-cutting change.

    What it really boils down to is this:

    If you recall a few years ago, this “double wall” craze started and now a multitude of stores want you to pay $7.99 for a plastic cup. Well it doesn’t work. Period. That’s why home builders put insulation in the cavity between the walls of your home.

    “Double Wall” is just a marketing gimmick. It may keep things a little cooler or a little warmer for a little longer than single, but that’s it, and Stanley knows it.

    But if Stanley can save millions by producing an inferior product to unsuspecting consumers that rely on slick, pseudo-wholesome marketing and outdated testimonials -they’ll do it. At least for a while.

    This higher up indicated to me that they have no plans whatsoever of returning to the scary charcoal.

    In the long run; however, I predict that smart business will prevail after profits drop sharply.

    Then again, perhaps consumers will become accustomed to paying premium prices for their inferior product. We do it all the time -houses, electronics, refrigerators, clothes washers etc.

    In closing, don’t fret. If the latter scenario comes to fruition over the next couple of years, I will make the smart business decision and produce a new thermal bottle as a new brand from my company. We will utilize that dastardly charcoal, and it will be made in America.

    Please convince me to do it sooner and forward any comments or questions to:

    • Carolyn Shearlock
      Posted at 09 June 2014 Reply

      Interesting, but my “bad” Stanley bottle was purchased in 2008 so I’m not sure charcoal was all that great. The ones that are actually working for me are all vacuum bottles, with literally nothing as the insulation.

      • The Critic
        Posted at 10 June 2014 Reply

        Thanks for the reply. Stanley started “fazing out” the use charcoal at the end of 2008. By 2010 they stopped altogether, and the transition was complete. Your 2008 bottle is probably one of them or may have a broken vacuum.

        I have (6) 1.1 quart, and (6) 2 quart bottles made in 2007. After testing them with boiling water, sealed for 24 hours at a room temperature environment, they all measured at between 165 and 185 degrees, the lower readings from the 2 quart bottles.

        In reference to your un-insulated bottles, it is true that if you have a quality bottle with a solid vacuum AND an insulator like Styrofoam, charcoal etc. it will retain temperature. But you must have insulation in conjunction with the vacuum for the most retention. I would wager that if you cut your bottles that work in half (only by a trained professional) you would find some type of insulation.

        • The Critic
          Posted at 10 June 2014 Reply

          …by the way, I am a mechanical engineer that specializes in HVAC (heating, ventilation and air conditioning).

          • vrkelley
            Posted at 11 June 2014

            >>a new brand from my company

            Please post the “future” brand or company name so I can get one when it is available.

            The wide mouth apparently can’t cut it. Perhaps the redesign should have a 2nd cap that narrows the flask at the top (much like a drink thermos).
            Also posting this on your other thread.

          • The Critic
            Posted at 12 June 2014

            Thanks for your interest. As this would be a new company, it is not formed yet, so we do not have an operational name; however, if you send us an e-mail, we will notify you when it is available.
            A wide mouth jar is doable, but needs an insulated cap, which, of course, Stanley and other companies are too cheap to produce.

    • texasgrape
      Posted at 10 November 2014 Reply

      You are incorrect. Double wall works if sealed with an inert gas, or vacuum sealed. The fact you compared a house wall with a thermos says it all. My Stanley thermos still working after years and years. It’s double walled and sealed.

  • vrkelley
    Posted at 10 June 2014 Reply

    The problem with the 16oz Wide Mouth is that it doesn’t even keep foods @+140 over 8hrs. Package said 9hrs. For daytime thermos cooking esp. on a boat, there is a risk of food poisoning. The 24/32oz size is too big for 1 person so the leftovers end up spoiling. Hold your nose!

  • ugochi anyaka
    Posted at 21 June 2014 Reply

    I bought a Stanley,wide mouth, in 2013 on a visit to the USA. We paid a huge almost 80-100dollars for it, and it worked well, retaining heat for atleast 24hrs. In Nigeria, I travelled to a ‎new city and forgot my precious flask at a friend home, so meeting my 1 year old’s warm feeding need was a challange. When I finally got it back after 6months, I had stopped working. I am so heart broken. I can’t ask my friend what exactly happened, or maybe I should ask if it was being used this 6months, or if it hit the floor. Do all steel Stanley flasks go bad when left unused for months? Do they also gop bad when they get hit? I am definetly following up on the life time warranty when next I visit the US or start byy finding their customer care contact online and begin the process from here.
    I enjoyed reading about your test Carolyn, and reading all the reviews/comments.
    Last thing, I’m an environmental journalist, and charcoal is a bad one for the environment. That said, I still need a working product from Stanley. Good product versus planet in harmony!

  • JT
    Posted at 04 October 2014 Reply

    Did you measure out the same volume of water for each flask? If not, and you just filled them to the brim, then your methodology is flawed. For the same reason that it takes a lot longer to boil a lot of water compared to less water, the heat-loss is proportional to volume.

    When equal volumes of water are used, one would still expect the advantage to go to the largest flask, because it has the smallest surface area. So, it still wouldn’t be a fair test. However, if you know a good mathematician, it must be possible to calculate different volumes for each flask to match their surface area, such that none has a size advantage/disadvantage.

    • Carolyn Shearlock
      Posted at 04 October 2014 Reply

      They’re all approximately a quart. Each is slightly different, but yes, I filled each to its “fill line” because air in the bottle will affect the results way more than the tiny difference in volumes (only a couple ounces difference at most).

      • Bob
        Posted at 23 October 2014 Reply

        I can’t testify to the worthiness of the Nissan vs. the Stanley but I can report that I have a 1.1q Stanley that I bought new about 3 years ago and am very satified with. I only use it for coffee. I preheat it with hot tap water (and most times the hot water goes in 8 to 9 hours before I make the coffee.) I usually don’t start drinking the coffee until about 6 hours after pouring it in the Stanley and then drink from it for about 6 hours, usually with a cup or two left over. I have always been pleased with how long it willl keep my coffee hot. I have noticed that if I open and pour from the Stanley earlier than normal that by the end of my shift the coffee is noticeably cooler than I would like. I assume that is caused by the introduction of room temp air into the thermos. There have been a few times when I didn’t drink any of the coffee during my tour of duty and 24+ hours later the coffee was still very drinkable and I can’t stand luke warm coffee. If the Nissan performs better than this I want one.

  • vrikelley
    Posted at 24 October 2014 Reply

    My newer Nissan leaks like a sieve. I have some rigid white closed-cell foam from a home construction site. I’d like to make a small mold for it i.e., the bottom half holds the thermos on its side; the top half lifts off. I’m not sure how to carve the mold with accuracy. Did anyone else try this?

  • texasgrape
    Posted at 10 November 2014 Reply

    As for the Stanley not holding heat, it’s guaranteed for life people. If it doesn’t hold heat, it has a nitrogen leak and the gas barrier is gone. Send it to Stanley and they will give you a new one free. I’m on my 3rd one in 40 years! Screw the glass lined ones, they’ll break unless you want to treat it like a sissy. Stanley lasts a lifetime and they guarantee it. Gas leaks eventually from everything, just send them your Stanley thermos and they will replace it. BTW, I just did a test on mine that is now 10+ years old. Not rocket science people, I filled it with hot coffee and it was HOT 6 hours later, and VERY warm 24 hours later; I drank me a cup.

    • texasgrape
      Posted at 10 November 2014 Reply

      Correction: Some used to be filled with nitrogen, some vacuum sealed. Stanley’s are vacuum sealed and if there is a leak, they don’t work. Again, just send it back for a new one, it happens.

  • john lucier
    Posted at 13 December 2014 Reply

    A lot of overthinking this going on here…. to the blog author, from the performance described it sounds like your Stanley has completely lost its vacuum. They tend to either have it or leak it all at once- though there is an acceptable leak rate (expressed in pressure over seconds x like 10 to the 9th power…comes out to years)
    Stanley products from China have a pretty significant failure rate. My 1.4 qt bottle had great features and the twist to drink cap was the best. Temperature retention was as good as any I have used… for about a month. Then without warning or abuse it completely failed. The many poor reviews on Amazon suggested returning it would just see me get another quickly failing bottle.
    Its all about the vacuum and the most absolute way to check it is fill it partway full of ice water and dry the outside and set it on the counter. If condensation forms the vacuum is gone.
    Its true Nissan used to make some of the best bottles out there. As I believe they are now also made in China who knows.
    Based upon the many excellent reviews I just ordered a Hydro Flask 40oz bottle to replace the Stanley. Hopefully I will get at least a few years out of it.

    • vrkelley
      Posted at 27 January 2015 Reply

      How does the Hydro Flask stack up compared to the bottles the author tested? Got any temperature readings?

      • john lucier
        Posted at 27 January 2015 Reply

        No objective numbers but after a month plus of daily use i would say the hydroflask has fair to good tempersture retention, not quite what I experienced in the past with an older japan made nissan or even the newer stanley which I cant recommend due to its well reported durability issues which I also experienced.
        I think the hydroflask is decent quality but compromises temperature retention for its size/capacity ratio aa the distance between walls and thus vacuum thickness is very slim. Perhaps 1/4″ to 3/8″ at best. I would estimate that old nissan had about 1/2″.
        Im happy with it so far after I added a handle (same one I used on both the stanley and nissan with a few adjustments. Made of heavy ss aviation wire clamps and a piece of aluminum pipe) though when summer heat comes we will see about that temp retention. If that was my number one priority I would look elsewhere.
        One neat thing about the hydro flask that makes the newer nissan a non starter is you have the standard lid and two options- a flip top lid and a flip up sipper straw. The nissans and most thermos has a decidedly non innovative screw on pour stopper. Great for pouring coffee but I want to have it in the car and quickly take a drink and not have to worry about a loose lid. I can do that with one hand with the hydroflask though you have to watch that flip lid it can easily pop open.
        I did like the stanley solution…. unscrew half a turn and pull up and drink spill free right out the top. Too bad the quality is so poor.
        BTW the hydroflask was $35 shipped including the $5 optional flip lid at REI when they had them 25% off. Not sure now.
        What made my decision was the amazon reviews score on it. Overwhelmingly positive.

        • john lucier
          Posted at 27 February 2015 Reply

          FWIW the hydro flask lost its vacuum at about 2 months like the stanley did. REI replaced it no questions asked. Hmmm..

          • vrkelley
            Posted at 27 February 2015

            Look around for scrap that is laying around the house. Some months back, I used some neoprene from an old wet suit. I made a cylinder by stitching it together and it has a drawstring top. This worked well and overnight, the oatmeal is about 139F after 8hrs. So I made a second one from an old Mouse pad (also neoprine)…and used an old sweater sleeve to hold it in place. The neoprene wet suite version is worthy to take out in public. But both work well

          • john lucier
            Posted at 27 February 2015

            I dont know that the sleeve would improve temp transfer that much but I would be interested in the neoprene sleeve for drop/shock protection as it seems these are more fragile than we think.
            When I needed a hernia support I made one out of a wetsuit I got from a thrift store and some velcro. That stuff stitches well on a machine.
            I made a handle for my nissan years ago with a piece of aluminum jack handle and two ss aviation cable clamps that have silicon lining. With a little hardware adjustment I transferred it to the stanley and now the hydroflask.

  • starwish246
    Posted at 26 February 2015 Reply

    Thanks for the test results. I have several Stanley wide-mouths.
    Maybe a 2 layer heavy fabric (denim) bag with a bubble wrap center, would hold in the heat, longer. I hope that it works.

    • john lucier
      Posted at 27 February 2015 Reply

      They do make insulated lunch bags of a somewhat similar construction… only the bubble wrap has a metalized film type composition, possibly mylar. Be a lot cheaper to buy one of those than make your own if you could find one that fits.

  • Bill
    Posted at 08 March 2015 Reply

    It’s very important to remember that boiling water added to a cold thermos cools about 10-15 degrees from the initial shock of cold walls and cold proximities to the other side of the Stainless Steel Wall. Remember that you thermos holds whatever temp it is given minus adverse temps that reside in the vacuum space. This has a cooling effect and shortens the length of time that that the average temp will be desirable. On the less expensive China thermos, be sure to preheat once for the cold thermos for 5-8 minutes, and then do an additional preheat for 5-8 minutes with boiling water. You will be surprised at the difference this will make even taking temp readings 24 hours later. Vacuum is non-conductive and better than insulation, but it is also cold unless it is heated and that is a tough hard to reach area to be warmed up in 5 minutes, ergo the second pre-heat. You will have great luck with even the China product if you follow these procedures. One other note, both gaskets or off-sets need to be engaged in the screw on top, the bottom one that mashes against the offset in the stainless steel, and the upper flange towards the top of the cap. We sometimes don’t want to put the lid on too tightly in fear we will damage the unit…. that was true with the glass lined models, but is NOT true with the stainless models. Screw it down tight to be sure it has a 360 degree seal, even if the bottle has not deformed over time, the gasket will sometimes have an irregular memory and you may only have partial seal instead of the whole 360 degrees needed. If you can find them, I usually order 3 or 4 replacement gaskets for the bottom of the stopper and replace them once in awhile if they seem to be losing their memory.
    Sorry this was so “Wordy” but I just wanted to tell you what I have done in the past to much success.

    • scottsasonic
      Posted at 25 September 2017 Reply

      It’s important to pay attention to what is written. She clearly stated she pre-heated the bottles.

  • Ernie
    Posted at 01 November 2015 Reply

    I got a new Stanley 1.1Qt at REI and tested it against an old Nissan 48 oz I have. Filled both with boiling water for 10 minutes, then filled again. All the temps were taken with a meat thermometer at the top of the bottle, so at the bottom they would be lower, I guess.

    Initial temperature in each 205F.

    After 6 hours, Stanley 190, Nissan 195F

    After 18 hours (and the first quick opening), Stanley 150, Nissan 165F.

    After 24 hours (and two quick openings), Stanley 148, Nissan 160F.

    Higher Nissan numbers no doubt due to higher volume, but both looked good to me.

  • Zach Smith
    Posted at 07 December 2015 Reply

    Hi this test is unfair to the Stanley. It is a food jar, it has a much larger opening than both the the glass lined bottle and the Nissan bottle. I have a regular 1 liter green classic Stanley bottle and the 17 oz food jar and they both do a fine job keeping my iced tea ice cold, and my soup as hot as the minute I took it off the burner. In fact it does a much better job than the thermos King 16 oz food jar I had before especially with chunkier soups which lost more heat in the thermos bottle. In short the larger opening on the bottle the more heat you will use.

    • Carolyn Shearlock
      Posted at 07 December 2015 Reply

      I’m glad you’ve had good luck. I now have an even larger-mouth Thermos Nissan, and it keeps its contents far better than the Stanley. I think that some people have Stanleys that work well, but for most they don’t. And since they’re not consistently good, I don’t want to recommend one.

    • Ernie
      Posted at 06 July 2016 Reply

      No, this was the green classic I tested.

      Also, I came across a 61oz Nissan in the back of a closet and tested it. It was phenomenal, going in at 210 degrees and 30 hours later having dropped to 190.

    • scottsasonic
      Posted at 25 September 2017 Reply

      It’s not unfair. when capped it’s the same thermal physics. Why the cognitive dissonance? Are you a share holder in the company?

  • Mike Kean
    Posted at 11 January 2016 Reply

    I got a Stanley one-hand insulated mug for Christmas and I decided to use it today. I got coffee this morning and heated it up hot then poured it into the thermos and shut the lid. That was at 5:30AM today. It is now 11:03AM and I still cannot quite drink my coffee yet without burning my mouth. And I did not do any pre-heating. Just took the hot coffee from the microwave and poured it into a less-than room temperature thermos and capped it. I can feel a bit of warmth but only at the very top between the lid and the metal. This is only a mug and the thickness is not very much but I know for a fact the only reason I feel the heat is simply the way metal can conduct heat and transfer it up the screw in the cap. The rest of the mug is cold. This mug has an advertised “hot for 7 hours” rating and so far six hours later, its still hot (not warm, HOT).

    From a scientific standpoint, this testing was not controlled because there were multiple differences between the bottles. The test should have been done with all containers having the same holding capacity, and have similar materials. They should also all be manufactured in the same year and have only minimal use prior to testing. The amount of water should be equal in each container and making sure all seals are tight. You may also want to have a control test where the bottles are not pre-heated as some companies recommend different times for pre-heating.

    • Carolyn Shearlock
      Posted at 11 January 2016 Reply

      Yep, I said it was kitchen sink testing and not necessarily scientific. And I only used one of each model, and yours could be different . . .

  • Amy Burlette
    Posted at 08 February 2016 Reply

    I did a comparison with my hydroflask thermoses, I love them. I did a whole blog post on them.

  • Amy Burlette
    Posted at 07 February 2016 Reply

    I did a blog post on Hydroflasks a couple months ago. I absolutely love them! I have a huge Nissan Thermos but I wanted more sizes. (and colors) We are the proud owners of several Hydroflasks and a couple of their pint glasses. Right now we mainly use the 32oz size for ice water, the 18oz size for coffee and the glasses for beer. You can find them cheaper used on amazon, I’ve picked them up for great prices that way.

  • Charlotte
    Posted at 08 February 2016 Reply

    I absolutely love my Zojirushi stainless 25 oz lunch jar, it has a wide mouth and is great for thermos cooking, keeping things icy cold or hot. Before we’re underway, I’ll start a thermos meal and after a few hours, we have hot food without having to fire up the stove. We’ve even had fully formed cubes of ice after a weekend on the hook. This might be a good one to try yogurt with, as it has a wide mouth. For beverages, we use Hydroflask or Kleen Kanteen, icy cold or scalding hot hours later. Thanks for sharing your findings.

  • Mary Deyo
    Posted at 09 February 2016 Reply

    I just checked the links to the REI and Thermos Nissan products and neither product is currently available.

    • The Boat Galley
      Posted at 09 February 2016 Reply

      Just updated them both! Hate when they change links like that!

  • scottsasonic
    Posted at 25 September 2017 Reply

    Thanks for sharing. I predicted this outcome..only because of physics. And I have experience with those Stanley bottles.. they are the classic work site thermoses which always give you luke warm coffee even by the time you get to the work site, let alone having a coffee at break time. We always had to put them in a insulated bag which improves them 10 fold. They are seemingly more durable that’s the only plus. You are a service to the internet community.

  • john w
    Posted at 12 October 2017 Reply

    I Own 11 Stanley Flasks and I don’t why so many people are having issues with them because I have done some extensive testing and all I can say is a lot of the issues are more related to how the Flask is prepped,

    Well I have tested 6 of these Flasks from a 38 year old 1979 Vintage model known as the Aladdin STANLEY in perfect condition which has Charcoal packed solid between the inner bottle and the outer skin and they have a much smaller opening compared to the Modern version and they also do not have a rubber seal in the Cap, and one thing I don’t like about the older models is that they have a over lapped seam on the outside about an inch down from where the cup sits which can rust at this area and the Bright Chrome Base can become pitted and also Rust where it joins the main Tube, One thing I do like is the lack of need for a rubber seal and the fact that prior to the late 80’s/90’s they did not have a handle to rust where they joined the body or to have the welds break,

    The newer versions do not have that seam below the cup and all the Chrome work is now replaced with Stainless Steel So no more Rust problems, happy days thumbsup
    If anyone prefers the Vintage look/style then I would look on the net or in shops for the 1.1 QT / 1L 100th Anniversary model because they do not have the handle to break and it has a cup like the Vintage models which has a rolled top unlike the normal Classic series, One thing all this testing has laid to rest is the tales of how the older ones were better, “they are Not” If anything the newer ones stay slightly hotter and they don’t have seems that rust, Some of the Anniversary models have handles some don’t.

  • Johnw
    Posted at 12 October 2017 Reply

    Can anyone tell me what happened to my Post,

    thank you

    • Carolyn Shearlock
      Posted at 13 October 2017 Reply

      I read all comments before approving them to make sure there is no spam. And since there is only one of me, and I’m writing articles, replying to emails and doing other things, as well as the fact that I’m not online 24/7, sometimes it can take a few hours for comments to be approved.

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