Need help converting cake recipe from 9" round to 14" round (3 layer)
I've been asked to make one of my favorite cake recipes (for a 9" round cake) as a larger, 14" round cake for a party (3 tiers). Can someone tell me how to calculate the increase? I also know I need to adjust the leavening differently so it doesn't collapse. Would appreciate any advice or formulas you might have.
OP here. The cake is 1 cake with three layers, each the same thickness as the original so the 2.4 seems correct. I'll have to figure out how to adjust the leavening accordingly. It seems I'll finally have an excuse to purchse RLB's book!
Thank you so much for your help!
OK...I just looked this up the cake bible for you...and it's so damn complicated I'm not going to try to give you an answer 'cause I might do it wrong. She says that as the cake pan size increases, the amount of baking powder DEcreases in proportion to the other ingredients. The chart she gives shows a difference of 1 1/8 tsp vs. 1 1/3 tsp "per base", whatever that is (requires another chart). This leads me to believe that the differences are so minor that it explains why my cakes were fine w/ no modification.
OK so here are my thoughts on the calcuation.... what you need to calc is not an area (inches squared), but a volume (inches cubed). And, yes if you assume the pan in 1 inch high, the numbers are the same.
So for two 9X1 inches pans you need 128 (2X64 ) cubic inches of batter.
And for three 14X1 pans you need 462 (3X154) cubic inches of batter.
462 divided by 128 = 3.6
You need to multiply your recipe by 3.6.
Anyone concur? Am doing this correctly do you think?
i assumed that the OP's recipe made THREE 9-inch layers, not the two that you are assuming. If everything is the same, pan height and number of layers, then DebL's calc would be correct, but your's is correct if the original recipe only made 2 layers.
I have modified a cake recipe in this way to make a 12inch cake and I did not have to adjust the leavening. However, 14 is a pretty big cake, and Rose L.B. has a table in the Cake Bible that tells you how to adjust leavening to convert to larger size pans. And of course it will cook more slowly.
Assuming the cakes will be the same thickness, you multiply by the difference in square inches for the size of each pan:
9-inch pan: 3.14 (pi) x radius (4.5 inches) squared = 64 square inches
14-inch pan: 3.14 x 7 squared = 154 square inches
154 divided by 64 = 2.4
Multiply the 9 inch cake by 2.4 to get the 14 inch cake.