Buttermilk and Sour Cream – Why and How We Use Them in Cakes

A simple recipe for cake calls for flour, sugar, butter, and eggs. That’s all you need to bake a cake. But plain cakes can go only so far. Adding different flavors to the cakes takes them altogether to a different level. We can experiment with different flavors by adding various liquid ingredients like milk, buttermilk, sour cream, yoghurt, condensed milk, juice, liquor, fruit pulp, etc. or dry ingredients like milk powder, coffee powder, brown sugar, spices, corn starch, fruit powder, etc. While, all the additional ingredients lend their special flavor to the cake, some ingredients just get inter-mixed with the cake and we don’t get their additional taste. Buttermilk and sour cream are two such ingredients. They blend so beautifully with the other ingredients of the cake without strongly influencing the flavor. If you are a seasoned baker, you will be habitual of using buttermilk or sour cream while making your cakes, cupcakes, cookies, etc.

I do not fully agree when some bakers say that they use buttermilk or sour cream for it gives a tangy flavor to the cake. Because, I have not tasted the tanginess of buttermilk or sour cream in a cake full of butter and sugar. So, is there any other reason which makes buttermilk or sour cream so popular in cakes batter? Yes, and the reason is – both buttermilk and sour cream are acidic in nature. This acid breaks the gluten strands in the batter thus giving a tender and softer cake.

Let’s understand what are Buttermilk and Sour Cream

Buttermilk – If you are an Indian, you will have a different definition of buttermilk than Americans. In India, buttermilk refers to the white residual liquid which comes out when the milk cream is churned. As a result of this churning, the cream separates into fat and liquid. The fat that floats on the top is called butter and the separated liquid at the bottom is called buttermilk. However, in the US, buttermilk is fermented milk – milk fermented by the strains of lactic acid bacteria. In baking, we use the American version of buttermilk because we need the thickness and acidity of fermented milk.

Sour Cream – You will always remember what is sour cream if you call it soured cream instead of sour cream. That’s what it actually is. When you introduce acidity in to milk cream, you get sour cream.

Let’s compare Buttermilk and Sour Cream to get a better understanding

Buttermilk	Sour Cream
Buttermilk is formed when we add lactic acid bacteria into the milk.	Sour Cream is formed when we add lactic acid bacteria into the milk cream.
Buttermilk has more water content and less fat content.	Sour Cream is has less water content and more fat content.
You can make buttermilk at home by adding lemon or vinegar to the milk.	You can make sour cream at home by adding lemon or vinegar to the milk cream.
Method – In 1 cup of lukewarm milk, add 1 tbsp lemon juice and let it sit for 5 to 10 minutes. You will get a curdled milk mixture which you can use in your cake recipe.	Method – In 1 cup of lukewarm milk cream, add 1 tbsp of lemon juice and let it sit overnight or for at least an hour. After one hour, you will get curdled milk cream which you can use in your cake recipe.
Substitute – You can substitute buttermilk with yoghurt mixed/diluted with water.	Substitute – You can substitute sour cream with Greek yoghurt.

How to use Buttermilk or Sour Cream in your Cake Recipe

Since both buttermilk and sour cream are acidic in nature, they need to be balanced out in the cake batter with the alkaline ingredient. For this reason, in the recipes where we are using buttermilk or sour cream, we use baking soda at the main leavening agent. Baking powder may or may not be used as baking powder is acidic in nature.

You can always substitute milk in your cake recipe with buttermilk to add that extra flavor and texture to the cake. Sour Cream will add more fat to the recipe and will make the cake dense and heavy. So, you should be careful while adding sour cream to your cake batter.

As mentioned in the beginning, buttermilk and sour cream tenderize the gluten, that is, they break the gluten web. For this reason, your cakes turn our extra soft and tender. Excess quantity of buttermilk or sour cream may make the texture of your cake so soft that it may collapse easily and may not hold on its own.