How to Scale Up a Cake Recipe

Not a recipe today after all the wedding cake antics I have a lot of catching up to do!

A question I get asked a lot is how to change a recipe to bake it in a bigger or different sized tin.

I have a full set of recipe sizes for Madeira, Chocolate and Fruit Cakes in The Busy Girl’s Guide to Cake Decorating from 6″ all the way through to 12″ round cakes.

But, I needed a 14″ round madeira for the wedding cake so I thought I’d do a post on how to work it out.

To scale up a recipe you first need a basic recipe and the tin it should be baked in.

You also need the tin you want to bake it in. Both should be roughly the same depth.

Here is my recipe for a 12″ round madeira cake

700g Butter

700g Caster Sugar

10 Eggs

530g Plain Flour

175g Self-raising Flour

105ml Milk

and here is the 14″ tin (it seemed like such a good idea at the time!)

Because the given recipe works correctly you can’t just go gung ho estimating that it’s say 1/3rd bigger because you will change the depth of the finished cake.

If the cake mixture is too deep you will most certainly end up with a volcano effect in the middle and the outside edges will be too overdone before the middle is cooked through.

So to find out the scale when enlarging a recipe….

Find out the capacity of tin A (the one that the cake should be baked in) and find out the capacity of tin B (the one you want to bake it in). Fill them with water to the brim (measure the water as you pour each jugful in rather than trying to measure it back out!) Write it down in millilitres.

Tin A (My 12″ tin) will hold 5 litres 200ml or 5200ml

Tin B (my 14″ tin) will hold 7 litres or 7000ml

Tin B divided by Tin A = Scale

7000 divided by 5200 = 1.346

In a world of digital scales multiplying ingredients by 1.346 would be fine, but not with eggs! So we need to adjust the scale to accommodate the eggs in the recipe. I fear I may lose you when you see the chart…. my brain is aching from typing it up! You have your scale, look down the chart to the row that matches the number of eggs in the original recipe. Select from that row the scale that is closest to the one you have worked out. That is the number you need.

Eggs Scale

2 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5

3 1.34, 1.67, 2, 2.34, 2.67, 3, 3.34, 3.67, 4

4 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3

5 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3

6 1.17, 1.34, 1.5, 1.67, 1.84, 2, 2.17, 2.34, 2.5

7 1.14, 1.28, 1.43, 1.57, 1.71, 1.85, 2

8 1.125, 1.25, 1.375, 1.5, 1.625, 1.75, 1.875, 2

9 1.11, 1.22, 1.33, 1.44, 1.55, 1.66, 1.77, 1.88, 1.99, 2 and onwards

10 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 and onwards

You can print the chart out – it’s much less bamboozling when you have it in front of you. Scaling Recipes

For me at 1.346 I need this line

10 1.1,1.2,1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 and onwards

rounded up to one decimal place 1.346 is 1.3

so I need to multiply all the ingredients in the recipe by 1.3

Butter 700g x 1.3 = 910g

Sugar 700g x 1.3 = 910g

Eggs 10 x 1.3 = 13

Plain Flour 530g x 1.3 = 689g

Self-raising Flour 175g x 1.3 = 227.5g

Milk 105ml x 1.3 = 136.5ml

round any rogue quantities ie. self-raising flour goes to 228g and milk goes to 137ml

So my new recipe for a 14″ round madeira cake is

910g Butter

910g Caster sugar

13 Eggs

689g Plain flour

228g Self-raising flour

137ml Milk

I just need to find something big enough to mix it in.

I hope that hasn’t completely put you off, scaling recipes is easy once you have an example to work with. You can use this method to bake pretty much any cake in any type of tin. Keep the oven temperature the same as the original recipe but keep your eye on the baking time, of course the more cake mixture there is the longer it’s going to take to bake. I’m sure there’s a mathematical equation for that too but I’m afraid it’s beyond my limits!

Oh and if there’s a computer/maths whizz out there that can make a little program for doing it instead of the chart please give me a shout!