calculations for Chocolate cake
Posted: 27 May 2017 08:59 AM   [ Ignore ]
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I have made the chocolate cake many times from the cake bible using the base formula.  In the next week I want to make a 10 inch square so am using Factor 7 for a 12 inch round.  I wanted to try converting the cake to the same recipe as the Chocolate Layer cake on Page 104 of Heavenly cakes where some of the butter has been replaced with oil (15-20%)  I noticed that, on the 9 inch, there is about 20g difference in the butter between the 9 inch round (using the formula) in the Bible vs Heavenly cakes (less in the Heavenly cakes). The butter calculation probably won’t make much difference but the Baking powder requires 6 tsp for the 9 inch double layer in the Cake Bible and 4 tsp for a double layer in the Heavenly Cakes.  Could you advise how to convert the cake - which calculation should I use for both the butter and the baking powder
Thanks Lesley

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Posted: 22 June 2017 04:51 PM   [ Ignore ]   [ # 1 ]
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I don’t know what all that Rose factor stuff is because I don’t have that particular book and her quirky methods aren’t taught in culinary schools.

But I do have a heavenly cakes. I’ve been taught how to scale by national culinary standards. To convert the recipe from a single 9 inch round to a single 12 inch round you first need to find the area difference between the two round pans.  But doing the calculations, you will see that the 12” round quantity is too much for a 10” square.  Makes better sense to scale the the 10” square.

So here’s all the math. At the bottom I include the recipe scaled to a 10” square.


The area is the radius squared multiplied by pi. 
The radius is half the diameter
Pi = 3.14

9” is the diameter       So divide it in half for radius
9 divided by 2 = 4.5     Now square the radius
4.5 x 4.5 = 20.25         Now multiple by pi
20.25 x 3.14 = 63.65

Area of 9” is 63.65”

///////

12” is the diameter         So divide it in half for radius
12 divided by 2 = 6       Now square the radius
6 x 6 = 36                   Now multiple by pi
36 x 3.14 = 113.04

Area of 12” is 113.04

Divide larger pan area by smaller pan area

113 divided by 64 = 1.765

Look at the number to the RIGHT of the decimal point.  That tells the the percent to increase the batter. The 12” pan requires 76% more batter.

So you need 1 full recipe PLUS 76%


STOP!  you state that you want bake a 10 inch square cake.  But you intent to use a 12” round pan as the basis for the conversion. You will end up with about 20% more batter than you need.

To find the area of a square you simply multiple the length by width.
10 x 10 = 100.

The area of a 10” square is 100”
Divide the larger size pan into the smaller size 9” pan from the recipe

100 divided by 64 = 1.56

The 12” round requires .76 more batter
The 10” square requires .56 more batter

20% is a significant difference.

So it makes more sense to scale the recipe to the 10” square and not the 12” round.


Since .56 is close to 60, for ease of calculations, you can use .60. 

Unsweetened alkalized cocoa powder 42 g
42 x .60 = 25.2 You need an additional 25.2 grams cocoa powder
42 + 25.2 = 67.2 cocoa powder

Boiling water 118 grams
118 x .60 = 70.8 You need a additional 70.8 grams boiling water
118 + 70.8 = 188.8 gram boiling water

Whole eggs 100 grams
100 x .60 = 60   You need an additional 60 grams of whole eggs
100 + 60 = 160 grams of whole eggs

Water 44 grams
44 x .60 = 26.4   You need an additional 26.4 grams water
44 + 26.4 = 70.4 grams water

Cake flour 156 grams
156 x .60 = 93.6   You need an additional 93.6 grams cake flour
156 + 93.6 = 249.6 grams cake flour

Sugar 200 grams
200 x .60 = 120 grams   You need an additional 120 grams sugar
200 + 120 = 320 grams sugar

Baking powder 2 teaspoons OR 10 grams
2 x .60 = 1.2   You need 1.2 additional teaspoons baking powder
2 + 1.2 = 3.2 teaspoons baking powder
OR
10 x .60 = 6   You need 6 grams more baking powder
10 + 6 = 16 grams of baking powder

Salt 1/2 (same as .5) teaspoon OR 3 grams
.5 x .60 = .3     You need an additional .3 of a teaspoon
.5 + .3 = .8 of a teaspoon of salt
OR
3 x .60 = 1.8 grams   You need 1.8 grams additional salt
3 + 1.8 = 4.8 grams salt

Butter 113 grams
113 x .60 = 67.8   You need an additional 67.8 grams butter
113 + 67.8 = 180.8 grams butter

Oil 28 grams
28 x .60 = 16.8   You need an additional 16.8 grams oil
28 + 16.8 = 44.8 grams oil

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