Just because one recipe calls for a nine-inch round cake pan doesn’t mean you can just dump the batter into your eight-inch square without modification. Cooking is chemistry, and all too often substituting pans doesn’t work out well, something burns. This is where knowing the volume of various shapes come in (the chart is above).
For example, an eight-cup measure holds roughly the same amount of batter in both an eight-inch square and a nine-inch round. With some adjustment in cooking time, you might be able to switch those two pans around but you’ll need to keep the shapes in mind. Because a square pan cooks more quickely in its corners than the middle of a round one, you’ll want to monitor the edges carefully. The heat moves through the batter in a different way in every shape.
Why Pan Size Matters in Baking
The filling: This is where most of us go wrong as home bakers. We’ve all done it (wanting a tall cake), we pour in our batter until the pan is looking full. But we forget about how batters will rise. For light batters such as angel food and chiffon, fill the pan only half-full, leaving plenty of space for them to expand. For denser cakes like a pound cake, which don’t rise quite so much, the pan can be filled three-quarters full. Failing to account for these ratios lead to overflowing the pan, and guess what’s next? Yes, a mess inside the oven, with sticky residue and smoke from the burned-on mix sticking to the oven rack. It’s a small detail but it makes all the difference between a professional-looking loaf and a chaotic spill.
Not only does the shape matter (obviously), but also the material. If you cook with glass, it takes time to get hot but retains that heat well so you’ll want to drop the oven temp by 25 degrees or so, because the edges will burn while the middle is still baking. Same goes if you have dark-colored metal pans: They absorbs heat fast, so be sure to test those cakes sooner. And then there’s silicone, which doesn’t conduct heat very well and is flexible… But expect to add some extra minutes onto your bake if you go this route. Expectations vary from material to material; don’t look for just one best.
The math is easy: When you scale up (or down) a recipe, it’s as simple as determining the volume relationship between the pans you’ll be using then multiplying all ingredients by that number. Doubling the size doesn’t mean doubling the cooking time. A bigger pan means a thicker cake, which will require more time; but a wider surface area changes how moisture evaporates. Go by toothpick rather than timer.
And then there’s preparation. Are you using a regular old round pan? Flour it and add some grease and your cake will come right out. Are you using an elaborate Bundt pan? Mix some breadcrumbs (or even better: sugar) and butter to form a barrier between the cake and the pan, preventing any broken pieces as the cake pops loose. Got an angel food cake in mind? Leave the pan naked, it must cling to the walls in order to rise properly.
All this knowledge belongs on the journey called baking. Instead of blindly following baking directions, learn about the connection between heat, volume, and texture. Understand why the pan size is important and go ahead and swap them out. Know what your cake should turn out like, and make your next one just that.