Changing the Pan Size

So many times in the boat galley, we don’t have the exact size pan called for in a recipe.  While meat, casseroles and vegetables generally aren’t all that picky about the pan size, the situation is different with cakes, breads, desserts and other “baked goods.”  In this article, I’ll pass on some tips about how to successfully use a different size pan — and the key isn’t what a lot of other online sources say it is!

For baking, the best pan substitutions are those where the batter is the same depth as was originally called for.  In that case, you won’t have to change either the temperature or the time in the oven.  The area of the bottom of the pan is the key to figuring this out.

• If you increase the area, the same amount of batter will be shallower. When the batter is shallower, the center will dry out faster than originally.  Compensate by decreasing the baking time and raising the temperature so that the outside will still brown in the shorter time.

• If you decrease the area of the bottom of the pan, the batter will be deeper and the center will be underdone at the original time and temperature.  To compensate, lower the temperature and increase the baking time.

So figure out the area of the pan called for in the recipe, and then the area of the pan you have.  (The areas of common pan sizes are at the end of this article, as are the formulas for calculating the area of other pans).  If the two numbers are within 10% of each other, you shouldn’t need to make any adjustment.  Otherwise, adjust the time and temperature as described above — the exact amount of the changes will depend on how much the depth of the batter has changed.

For example, if a recipe calls for baking in an 8×8 pan (64 square inch bottom) but you have a 9×5 loaf pan (45 square inches), the batter is going to be almost 1-1/2 times as deep. (To figure this, divide the original pan size in square inches by the new pan size = 64/45 = 1.4).

Since it will be deeper, lower the temperature 25 degrees and begin testing for doneness according to the recipe directions at the original baking time plus ten percent (it probably will take about 25% more time, but I’d rather start checking too soon than too late).

Remember, the important thing is how deep the batter will be in the new pan compared to the old pan, not how deep the actual pans are in comparison to each other or what the total pan volume is.  I have seen a number of pan size conversion charts online that talk about using a pan with the same total volume (it appears that they were all copied one from another since every word is identical) but the reality is that what’s important is the batter depth, not the total volume.

The same concept applies if you halve a recipe or double it.  For example, if you make half a recipe, you want a pan that has about half the area of the original pan – or you’ll have to compensate for the difference.

Here’s the area of some common pan sizes:

Formulas for calculating your own:

• Square or rectangular pan:  Area = length x width
• Round pan:  Area = (1/2 x diameter)² x 3.14

If you have to calculate the area on a pan with sloping or curved sides – a pie pan is one example – measure the length, width or diameter halfway down.