Wow. I love my thermal cooker. It has made getting dinner SO much less hectic. Why didn’t I get one years ago?
What’s a Thermal Cooker?
A thermal cooker is basically a non-electric crock pot. It’s sort of a really big Thermos, but with a removable interior pan (or two). In short, you start your food cooking on the stove – browning meat, onions, whatever and then adding your other ingredients – and then put the pan(s) into the thermal cooker, put the lid down and let it sit for up to 8 hours.
The food cooks while you’re doing whatever else you want to, and all you do at dinner time is serve up.
Okay – that is a bit of an oversimplification. There are different techniques for different types of food. Some cook in the thermal cooker, others are cooked ahead of time and stay warm in the thermal cooker, and others may require a bit of “finish up” after cooking in the thermal cooker.
You may have seen pieces that I’ve written before about “Thermos Cooking” for rice and dried beans; this takes it to a whole new level of cooking a whole meal.
So What’s the Big Deal?
For me, the big deal is that I can cook whenever it’s convenient for me during the day, and it’s ready when we want to eat.
We tend to do things around the boat in the morning and then do bigger projects or things off the boat in the afternoon. I like to enjoy happy hour with Dave, or maybe we have friends over or go to their boat. For all these reasons, late afternoon is just a really hectic time for me to cook.
In the past, that means that usually I start dinner after we’ve had a drink for happy hour, and then we end up eating at 8 or so. But that’s not good for Dave’s acid reflux. So I try to have dinner earlier, and would manage to do it for a few days . . . then we’d get working on something in the afternoon and we’d revert back to the old patterns.
I’d seen thermal cookers in the past (a reader wrote me about one and I posted it here) and thought one could help, but they were really expensive for something that I didn’t really know if I’d find useful. The other option that I saw was the Wonderbag (read about it here) and while they were cheaper, they took a LOT of space to store.
Then around Christmas, I saw someone post on Facebook about the Saratoga Jack’s thermal cooker they’d just bought. There were several things about it that really appealed to me, including that it was cheaper (admittedly, still not cheap). I bought one.
All I can say is that I absolutely love it! I use it three or four times a week, particularly on days when I know we have something planned for the afternoon. I’m no longer constantly thinking about when I do have to be done with this in order to start dinner.
Other Benefits
In addition to letting me start dinner whenever I feel like it (more on this below), the thermal cooker has other benefits:
- Saves propane or other stove fuel as you use retained heat to do most of the cooking.
- Less heat in the boat on hot days.
- Less humidity in the boat since the lid fits very tightly as the food is cooking.
- I can leave the boat while the meal is cooking – whether for socializing, snorkeling, exploring ashore or even errands
- Great underway – start dinner before we leave, plop the cooker in the sink underway so it doesn’t slide, and open up to a ready meal or, on a longer passage, much shorter time spent with a pan on the stove
- Perfect for taking to potlucks – outside is cool and there’s a nice locking carry handle
- You can also use it for taking cold foods to a potluck by putting ice in the bottom pan and the food in the top pan – great way to transport salads or serve things like Jello.
The Basic Technique
Thermal cookers work on a simple principle of having food that is hot through surrounded by hot liquid continuing to cook. The secrets to success include:
- Having the food thoroughly hot through (watch out if you start with frozen meat or vegetables)
- Sufficient liquid boiling in the pan
- Very quick transition from the stove to being in the thermal cooker with the lid on
The fuller the thermal cooker, the less the food will cool down and the better it will cook. But because it does cool off slightly over time, food doesn’t over cook (unlike what can happen with a crock pot).
Here’s how it works in pictures. I’m making meat for tacos (pulled beef) in the big pan and dried white beans for the next day in the little pan (this was the first day I used it; I learned to put more water in both pans so there was more “hot mass” and less air space):
Bringing both up to a full boil — I like to boil on the stove for about 10 minutes so that it’s not just the liquid that’s hot, but the food in the liquid too. There’s only one lid with the set, but my 8″ round silicone trivet perfectly fits the small pan (buy one here):
Now it’s time to work quickly to get the pans into the thermal unit while they’re still as hot as possible. Take the lids off and put the small pan inside the big one:
Put the stainless lid over both (keep the big burner on until this step is done):
Slip the pans into the thermal container:
Put the latching lid on and place where it won’t be knocked over for 4 to 8 hours (I usually put it in the sink or wedge it on the floor):
Forgot to take pics of the finished dinner, but here’s the next night with white chili (using those white beans) and “recipe-ready” red beans for the next day’s Red Beans & Rice:
Starting Dinner When I Feel Like It
Some days, I may start dinner at 9 AM, others at 1 or 2 in the afternoon. How’s that work?
I’ve learned that if I let something cook a little longer on the stove, it needs less time in the thermal cooker. So if life interferes and I start cooking later than usual, I just let it go maybe 30 minutes on the stove and then put it in the cooker. If things really get out of hand, I can even cook dinner completely on the stove in late afternoon, then slip it into the thermal cooker (say while we have a sundowner with friends) and just keep it hot until dinner time.
I wouldn’t say that it exactly takes less actual time in the galley – I still do the same prep work – but the fact that I don’t have to “babysit” a lit stove and can do the prep when it suits me is HUGE.
What Cooks Well in the Thermal Cooker?
Anything that cooks in liquid or has liquid absorbed (such as rice dishes) is a candidate for the thermal cooker. Things that I’ve done and had great results:
- Chili – regular and white
- Pot Roast
- Soups
- Red Beans & Rice
- Jambalaya
- Gumbo
- Mexican-style taco meat (more like pulled beef, pork or chicken – all of which are also good)
- Spanish Rice
- Unstuffed Cabbage
- Spaghetti Sauce
- Swiss Steak
- Pork Chops (I cook in marinating liquid in thermal cooker until tender, then briefly in oven with BBQ sauce – based on this recipe)
- Curries (do rice in the top if desired)
- Corned Beef
- Ham & Beans
- Sloppy Joes
- Cooking the beef for Tropical Beef (see recipe in The Boat Galley Cookbook); I finished it with the veggies and thickening sauce on the stove
Things I’ve done in the top half:
- Rice
- Dried beans
- Boiled potatoes and sweet potatoes
- Hard-cooked eggs (boil water then put eggs in when you take the boiling water off the stove)
- Spaghetti squash (cooked in boiling water)
Thermal Cooker Techniques
I’ve only scratched the surface of what can be done in the thermal cooker, basically doing things that have plenty of liquid. The Saratoga Jack’s thermal cooker came with basic information on how to use it and a few recipes.
I also bought a thermal cooking cookbook which gave me far more in-depth information and ideas of other things to try – I find the book useful more for the techniques than the exact recipes. I found that I read through it more than using it as a reference, and thus the Kindle version (quite a bit cheaper) was just fine:
NOTE: The author comes to thermal cooking as a prepper and she’s fairly religious, both of which she discusses in the opening chapters of her book; some of her recipe plans are for food storage/prepping as well but can easily be adapted to other situations. Information on buying and using the thermal cooker starts in Chapter 5, “The Basics of Thermal Cooking” with a wide variety of techniques and recipes in the following chapters – she even tells how to make bread in the thermal cooker (I haven’t tried it yet).
Three Options for a Thermal Cooker
A bunch of different companies make thermal cookers. Through readers and my own experience, here are the three I’m familiar with:
- Saratoga Jack’s: This is what I bought. Foam insulated, which is not as good as vacuum insulation but works if you’re in a warm climate and take care to fill it full. In addition to the lower price, I like that it has two pans – one nests into the top half of the other like a double boiler. I can either cook two things (often I make rice or potatoes as a side dish or for a salad the next day, or I’ll cook dried beans to use in another dish the next day) or just fill the top with boiling water (I use it for dishes). This really helps to have enough “hot mass” in the thermal cooker when only making enough of the main dish for two people. Comes in a 5.5 liter size (mine) or 7 liters. Both have a heavy bottom on the larger pan (good when browning meats, etc. plus retains more heat); for the 7 liter unit, the deluxe version also has a heavy bottom on the small pan (there’s no deluxe version of the 5.5 liter model).
You can buy them on Amazon or on the Saratoga Jack’s website. When I last looked, Saratoga Jack’s had considerably higher shipping charges which more than offset the slightly lower price.
- Saratoga Jack’s 5.5 Liter Thermal Cooker on Amazon (Update: The Saratoga Jack’s Thermal Cookers no longer appear to be available on Amazon.)
- Saratoga Jack’s 7 Liter Deluxe Thermal Cooker (both pans have heavy bottoms) on Amazon
- Thermos: Comes in three sizes and is vacuum insulated (a plus) but only has one interior pan (a minus in my opinion) Update: Thermos now has a two-container thermos in a 6 liter size. Read Cathy Draeper’s recommendation. They are expensive with high shipping in addition.
- Thermos 5 or Quart, 6 Liter and 8.5 Quart Thermal Cookers
Wonderbag: With a Wonderbag, you use your own pots and place them into the Wonderbag. It’s a big insulated bag and while it works well, it is BIG to store (yes, it can squish down some). I just didn’t have room to store it and I didn’t have a large enough counter or other place to put it in use. The big advantage is that they are considerably less expensive. Read the full review here. Additionally, for every Wonderbag sold in the US, one is donated to a needy family in Africa. - Wonderbag
Other Brands
There are many other brands of thermal cookers; I don’t have experience with all. The biggest things to consider when looking at them:
- Size – if it holds way more than you want to make, there will be a lot of air space inside and it won’t cook well
- Insulation – vacuum insulation is best, foam second
- Number of pans – I find two is great as it gives me more flexibility (if I want to make a large batch, I can use just the bigger one)
- Pan bottoms – thicker is better; some will work with induction burners
- Size of the whole unit – where will you store it? where will it sit in use? can you put it in the sink or another safe place when using it underway?
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Jim Allen says
the cookbook is free for Kindles
The Boat Galley says
Yep, still free today. Don’t know how long it will be . . .
David says
Not free anymore: $20.65 on Amazon.com
Carolyn Shearlock says
The Kindle edition was free for two days — Sunday and Monday. I was working on this post when I saw it was free and posted on The Boat Galley’s Facebook page which also got Tweeted. I posted again on Monday that it was free — sorry you missed those announcements.
David Webster says
I’ve had a Mr Ds thermal cooker (aka Thermos Shuttle Chef) for years. It’s a vacuum type and has two inner pots, two lids and you can buy pudding, cake and bread tins to use in it as well. Worth it’s weight in gold.
The Boat Galley says
Those sound great! I haven’t seen that in the Shuttle Chefs currently offered in the US — apparently the Mr. D’s are sold only in the UK.
David Webster says
David imports them into the UK. He’s at a lot of the boat shows – and caravan shows for that matter. Here’s mine – less the accessories. Always in the kitchen ready. Although it’s in its carry bag at the moment…
Paula Turman says
May I ask what this cooker costs?
Thank you …
Sarah Garth says
I also have same Mr D’s Friends of Thermal Cooking cooker as David, it’s brilliant!
Pamela says
Curious about one thing–I found I didn’t use my crockpot on land as much as I thought I would because it made food mushy. I didn’t like the texture of chili in the crock pot as much as when I tended it on the stove.
Is this an issue with the thermal cooker? Or did you find the texture of beans and stews to be as good in the cooker as if you tended it on the stove?
Carolyn Shearlock says
I find the thermal cooker doesn’t tend to overcook things the way a crockpot can. I think that’s because a crockpot keeps adding heat over time, while the thermal cooker cools off very slowly. The beans and stews are great. About the only difference I notice is that with some recipes, I have to add more water than I would on the stove top (or less cooks away) and thus the “gravy” is a little thinner than if cooked on the stove. It doesn’t really bother me and with some thing (say chili, spaghetti sauce or Swiss steak) I use V-8 or tomato juice to add liquid instead of water.
Pam Dean says
I’ve been looking at these for months and you’ve convinced me to bite the bullet, especially with the free cookbook. Also, like the idea of reducing our footprint on the planet.
The Boat Galley says
Sounds like me . . . I looked for over a year before I bought.
pam says
Thank you for this wonderful article. I will read more about this but can you tell me how this would compare with using a pressure cooker and holding food under pressure to let it ‘slow’ cook? BTW the cookbook is also free to see in the Amazon Cloud reader.
Carolyn Shearlock says
I’ve never tried doing that in a pressure cooker myself, so I can’t make a good comparison. I think that the pressure cooker wouldn’t work as well as it cools down much faster — it depends on the food volume, of course, but usually the pressure cooker is pretty close to room temp after an hour. Pressure cooker starts out at a higher temp due to the pressure, but the pressure doesn’t do much to help it retain heat after it is removed from the stove.
Joan says
It is easy to make an insulated container for a crock pot. My crockpot is an older one and the ceramic pot comes out for cleaning. You could just take it out of the heating ‘container’ and put it into the insulated one. I use it to make yoghurt and at only 44 deg C going in it is still warm 12 hours later. You could do that with any pot of course but they are often different sizes and it really does need to fit well in there.
Sarah, s/v Mirador says
I just bought one of these! Haven’t tried it out yet, but love the idea. Thanks for the comment about putting boiling water in the top pot if you don’t have enough liquid, and for the link to the cookbook.
Pam Dean says
Hi again, I didn’t get the recipes in the free book although they are listed in the content page.
Carolyn Shearlock says
I think you may have downloaded the free sample or “first pages” — you have to “buy” the book for $0.00 to get the whole book.
Lyndy Atkinson says
Love mine too!
The Boat Galley says
They’re pretty similar. I just don’t have the space for the Wonderbag so it’s worth the extra expense of the other one. I wouldn’t think you’d want both unless there’s a large crew.
The Boat Galley says
For Pam Dean – make sure you didn’t download the “free sample” or first pages. You need to “buy” the book for $0.00 and then you’ll get the whole thing. If that’s what you did and you’re having problems, contact Amazon — I don’t have any connection to the book.
Ralph says
Cheapie 95% solution: At Walmart I bought a 2L Aladdin VACUUM bottle for _?_ . I don’t see it on Walmart right now, but they do show a 50oz Thermos for $41.
These are intended for coffee, but work fine for beans, smaller foods, Mine has a 2.5″ opening, which is pretty big. And they’re VACUUM, not foam, so better insulation.
LaMarr Harding says
Kuhn Rikon made an insulated pressure cooker some years back. Vacuum walls, two lids, and a sealed metal bottom. I don’t use it. Also have the Thermos 7 litre, from Japan, and the air-core with the insulated sides, two lids and thermometer.
If it doesn’t microwave, I don’t fix it.
Carolyn Shearlock says
Yes, we are a diverse group — I don’t have a microwave!
Deviant Dream says
Great article! My main reason for wanting a “crock pot” replacement for the boat is to make bone broth. Would this make bone broth?
Carolyn Shearlock says
I think you’re talking about boiling down bones from beef, chicken or turkey to make stock — right? If so, yes it works fine. You may want to heat it back up to a good rolling boil for 5 or 6 hours and then let it sit a second time, but I’ve done it that way with chicken bones and some veggies and it did wonderfully!
StarWish246 says
When my parents traveled in their RV, they would set up and start their slow cooker, and then go swimming at the lake or pool for hours. I was so worried that they could have a fire while they were away, and the slow cooker was unattended.
So, I bought them a Thermal Cooker. And, at least, I felt less worried about them.
P. S. The thermal cooker works great.
Margaret Morris says
Carolyn, I received a thermal cooker several years ago as a gift. I didn’t realize that it was actually a cooker and not just a thermal container for transporting hot food. This year we are planning an extended trip up the inside passage to Alaska. I got the thermal cooker out and I’m practicing. Today I used it as a dough proofer for my homemade French bread. I heated the outer container with hot water, oiled the inner pan and added my dough. Closed the container and let the dough rise. It kept the dough warm, secure and draft free. The thermal cooker has earned a place in my very small galley.
Carolyn Shearlock says
Great idea! You’re going to love it. And you’re going to love the Inside Passage. We did a three week trip (charter on a Morgan OutIsland 41 with a captain who became a great friend and convinced us we could cruise) in that area in the late 90’s and loved it! Breathtaking scenery and wildlife!
Margaret Morris says
Thanks Carolyn, In 2008 we took our CDory Tomcat 255 up the inside passage. It was an amazing voyage. We have been improving our boat, adding better heating, insulation and more batteries. We now have a 2000w inverter so we can power an electric pressure cooker or…our coffee maker or….our toaster oven. It is camping on the water but we love it. We always have incredible meals using a butane burner and the toaster oven. Thanks for all the great info!
Bill Coutts says
In Australia the equivalent Thermal cooker I use and have for years is the Dreampot.
It is fantastic. I even managed to make a cradle to hold it steady in one of our galley storage cupboards. It is great to prepare before you know you have 4 – 10 hours of fairly bouncy sailing to get to one of our islands in South Australia. On arrival its great to anchor and know that dinner awaits. There are other brands and they are not cheap but worth every penny.
Jeff Grant says
Susan Opladen
Susan Opladen says
I like it!
Deb Snella Temperly says
Thanks for the very clear introduction and explanation to this type of cooking.
Chris Hofmann says
Wonderbag
Deborah Woods says
Mr. D’s thermal cooker good piece of kit!
Michèle Boulay says
I have the Nissan brand & it is great. I’ve made the best pea soup, meatballs & sauce and even the Italian favourite for Sunday dinner, Braciole di Manzo (braised beef rolls).
Pamela Blanchard says
Carolyn, is your food storage book electronic only? Or can i get a hard copy from you?
The Boat Galley says
It is PDF only right now (can be read on just about any device) — you can, of course, print out a copy for yourself.
Matt Garand says
Skye this could be handy for the mooring!
Jonas Vignal-Olsen says
Det er vel egentlig bare en thermokasse, der bruger restvarmen. Ligesom når vi laver blødkogte æg
John Norman says
Had two for quite some time now, they are awsome
Darlene Luxton says
I have one too! Large to store but very convenient
Judith Nelson Cruzan says
That is a really nice set up. I’d seen some that looked like a quilt but didn’t feel like it could really hold the heat.
The Boat Galley says
Sounds like you’re talking about the Wonderbag. I looked at them but they are a lot bigger and I find this really easy to move around the boat, etc. Bottom line: I love it and wish I’d had it 15 years ago!!
Judith Nelson Cruzan says
The Boat Galley you know something is good when you feel that way about it.
Marta Crichlow says
Love mine. Now taking on a road trip!
Joy Harrison Canova says
Love mine. On a passage right now, and dinner is waiting.
Sharon Brown says
love mine. and it fits nicely in the small sink so never worry about it falling over etc. used it every day crossing the Atlantic
Ward Schmidt says
I have one at home and will soon purchase an offshore boat which I certainly will stock with another. We live in Japan and use it for cooking rice nearly every day as well as for beans. One thing I really appreciate is that one needs much less heat when cooking on hot summer days.
Katy Barth says
I have the Thermos cooker. I like it for all the reasons you mentioned in your article. But, I do have problems with volume. Has anybody got a suggestion for how to fill the cooker without adding more food or liquid? Sometimes I don’t want to add liquid because it messes with the recipe and sometimes I don’t want so much food (small fridge). I’ve been thinking of a bag of marbles or a jar of water with a lid. Has anyone done any experimenting?
Carolyn Shearlock says
That’s one reason that I like mine with two pans — I can fill one with just hot water (which I later use for dishes). I think your ideas would work but have not actually tried them.
Rebecca Nichols says
My husband and I are currently living on a sailboat. I bought the Thermos Nisson 4.5 liter a few years ago and found these same dilemmas – how do you get enough liquid in the pot to hold the heat without watering down the recipe? How do you fill it full enough to retain the heat without making enough food for an army?
If I had known about the Saratoga Jack version, I probably would have bought that, But then you lose the great vacuum insulation on the Nissan. Anyway, too late, I had already bought one and used it so couldn’t return it. SO – I found a site in Australia.
They are called Shuttle Chefs there, but the inner pans are the same as the Thermos Nissan. Don’t be too horrified by the price until you have the currency translated to your own. Then you can be horrified because it’s still expensive, but I found it to be worth it. I bought this “Bain Marie” pan two years ago. They do ship to the US, but it took a long time to get here, so be patient.
Now I have the great insulation (only need to boil for 5 minutes for most things before putting in the outer container), and the versatility of having two inner pans. I either use the top pot for rice, or I just put boiling water in there and then you can use less liquid in the bottom. Now I don’t get stuck with leftovers that won’t keep in a boat icebox.
I felt a bit ridiculous and embarrassed that I ended up spending so much $ on this, but now I’m so glad that I did. As my grandmother used to say, “Quality is remembered long after price is forgotten.”
Jack and Amy says
I loved reading this post…
Hi this is Jack from Saratoga Jacks!
Boat owners and also others who are energy conscience but love to live on the go too, like RV owners, tell us all the time why they love us, but you are one of the first blog posts we have ever seen online from someome who took the time to write about it. So thank you!
PS.
I just thought I would share why we use our propritary insulation versus a gas vaccuum sealed variety.
We actually tested several during development. Both kinds.
We saw that the vaccuum units failed more easily and frequently.
One good drop…micro movement
.and the seal failed and the entire unit became worthless.
Our cookers are subjected by our active users to camping, hiking, boating, kids soccer games, 4 wheeling, etc…and families just wear and tear on them. Frequently they get dented…and as long as they can still be shut…they continue to work. That was the difference.
Ours last 8 hours.
The vaccum seal units could have extened it to 10 hours.
Our customers after using both in trials…gave us feed back.
What we found in testing is rarely people went longer than 8 hours without meal, and that our customers wanted a guarenteed 8 hours… than a maybe 10 hours…but if dropped once could potentially never be used again.
The vaccuum models are less likely to be abused if only being used on a kitchen counter and never… being taken on road trips or subjected to being used in portable motion.
So although we had the option to provide a vaccuum unit… and seriously considered it…
We chose to go with a more rugged model…our customers are usually more adventurous people.
Hope that helps!
Lesa says
Jack, thanks for the input. I’ve been considering a thermal pot for a couple years. Your explanation is very helpful
Leland Parker says
Hello Jack and Amy. This is a revelation to me since I didn’t realize that anyone made an oversized thermos-type vessel for cooking. I’ve played with a thermal flask as sort of engineering experiment but the kitchen-sized version sounds like a must-have unit, especially where energy use and thermal leakage into a confined space are major factors.
I agree with your design decision to produce a more rugged unit and am reconsidering which model is best for me. To anyone who really wants that extra heat retention, you can always apply extra insulation to the thermal cooker by wrapping a dry towel or blanket around it. I melted the control knob a little on my crock pot this way when I wrapped a towel around it to get a higher temperature.
And thank you, Carolyn, for this fabulously informative web site and your books and courses. The value of good food on an adventure can’t be overstated. A happy crew is a good crew and a well-fed crew is a happy crew!
-Leland
Lulu Witt says
I loved the idea of your Thermal Cooker but your links no longer work and there do not seem to be any sold on Amazon at all anymore. Any ideas where you can still get them?
Carolyn Shearlock says
Hi Lulu!
I just checked and all the links to thermal cookers are working for Amazon in the US and units are in stock. They are also available on the manufacturer’s site: http://www.saratogajacks.com/
I’m not sure why you had problems with the links, but hope this helps!
Lulu says
Thanks for that. I’m guessing it just naturally directed me to the European site. Will try again. Cheers.
Carmie says
Hello
I just ordered the Saratoga Jacks 5.5 thermal cooker to use on our boat and was wondering if the pots can also be used for cooking when not using the thermal system – can I get rid of my two similar sized pots? I’m excited to start using the thermal cooker! Thanks for your great post about them!
Carolyn Shearlock says
Sure, no problem using them for other things.