How do you calculate ingredient amounts when scaling a recipe?
I have a cookie recipe that says to use 2 cups of flour to make 24 cookies. I want to make a bigger batch of 36 cookies for a party.
I'm a bit stuck on the math. How do I figure out exactly how much flour I'll need for the 36 cookies? I want to make sure they turn out right. Can someone walk me through the calculation step-by-step?
3 Answers
Hi @Baking_Finn, this is a perfect problem for using ratios! The easiest way to think about it is to find the "unit rate" first – that is, how much flour you need for a single cookie.
Step 1: Find the flour per cookie.
You divide the total flour by the number of cookies:
2 cups / 24 cookies = 1/12 cups per cookie
Step 2: Calculate the total flour for your new batch.
Now you just multiply the amount per cookie by your desired number of cookies:
(1/12 cups) * 36 cookies = 36/12 cups
Step 3: Simplify the fraction.
36 / 12 = 3
So, you will need 3 cups of flour to make 36 cookies.
Another great way to solve this is by setting up a proportion. You can create two fractions that are equal to each other.
Let 'x' be the unknown amount of flour you need.
Set it up like this:
(Flour 1 / Cookies 1) = (Flour 2 / Cookies 2)
(2 cups / 24 cookies) = (x cups / 36 cookies)
Now you can cross-multiply to solve for x:
2 * 36 = 24 * x
72 = 24x
Then, divide both sides by 24:
x = 72 / 24
x = 3
You'll need 3 cups of flour. This method is really useful for any kind of recipe scaling!
Here's a more intuitive way to think about it without too much algebra. You're trying to make 36 cookies, and the original recipe makes 24.
Notice that 36 is exactly 24 + 12. And 12 is half of 24.
So, you are making one full batch (24 cookies) plus one half batch (12 cookies). This is a total of 1.5 batches.
Now just apply that to the flour:
- For the full batch, you need 2 cups of flour.
- For the half batch, you need half of that, which is 1 cup of flour.
Add them together: 2 cups + 1 cup = 3 cups.
You need 3 cups of flour.