The Fresh Loaf

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Genoise cake conversion

Matther's picture
Matther

Genoise cake conversion

I have made Alice Medrich's Strawberry Celebration Cake (chocolate Genoise) from her book "Bittersweet" twice with great success. However, the recipe is for an eight-inch cake and I need to make a nine-inch cake.  Reading a 2011 post on this site where a reader wanted to know about using 9" pans for a cheesecake recipe that calls for 8" pans, in one answer you suggested that the bake should increase the recipe by 25% and in a further post, an increase of 21% is suggested.

Any help or suggestions you offer will be appreciated,

Thanks,

Rene

Weizenbrot's picture
Weizenbrot

...approaching the question geometrically, the 9" pan has a surface area of 4.5 squared times pi and the 8" pan 4 squared times pi, so the ratio is about 126%-127%. I'm assuming the 2 pans have the same height.

hanseata's picture
hanseata

Keiko's Cakes has a great cake pan conversion tool on her website:

https://keikos-cake.com/panconversion.html

To convert the recipe amounts for an 8-inch round cake to a 9-inch one you need to multiply every ingredient amount with the factor 1.27.

With Keiko's tool, you can convert round or square pans, in inches or centimeters. I use it often.

Karin

Matther's picture
Matther

Thank you!  This is awesome!

Norcalbaker's picture
Norcalbaker

First find the area of the circle for each pan
1. Radius is half the distance of a circle.
2. Square the radius (multiply the number by itself)
3. Multiple radius squared by pi
4. Pi is 3.14

Radius of 9" pan
9 ÷ 2 = 4.5

Radius squared
4.5 x 4.5 = 20.25

Multiply radius squared by pi (3.14)
20.25 x 3.14 = 63.58

The area of the 9" pan is approximately 63.5"

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Radius of 8" pan
8 ÷ 2 = 4

Radius squared 
4 x 4 = 16

Multiply radius squared by pi (3.14)
16 x 3.14 = 50.24

The area of the 8" pan is approximately 50"

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Now calculate the difference in percentage between the two pans.
Divide the area of the larger pan by the area of the smaller pan.

Area of 9" pan = 63.5
Area of 8" pan = 50

63.5 ÷ 50 = 1.27

You need to increase the recipe by 27%.