I would like to know the main advantage of using buttermilk as a hydrator and minor source of fat (1% fat, right?) in baking, over using regular milk or cream.

Since it's a byproduct of producing butter, I would suppose that early peoples developed recipes to use buttermilk solely, instead of remixing it with butter like in most recipes I see online -- though this is just a comment rather than a question, feel free to share any insights.

Backstory is I tried whipping my own butter to use in my cookie recipe. The results were absoutely superior (soft, fragrant cookies), since the butter still has some buttermilk left inside. I was able to produce the same yield whilst holding back one egg from the usual recipe.


2 Answers 2


Historically, milk was accumulated in the churn until there was enough to be worth making butter. The milk would, of course, ferment. Both the butter and the watery buttermilk took the sour, fermented flavor.

Modern buttermilk is different. It is low fat milk that has been cultured and fermented. It is thicker and creamier but has a similar soured flavor. (I've been told. I've never tasted historically fermented buttermilk.)

Therefore, historical recipes are not going to be the same as modern recipes that call for buttermilk.

The "buttermilk" left in your homemade butter would not have fermented and would not be similar to historical or modern buttermilk. It does have a good amount of sugar and protein, and of course water, that would affect your recipe.

In modern recipes, buttermilk is used to lower the ph, add a tangy flavor and a creamier texture than milk. The added fat is not usually a factor. Creamy buttermilk can be made with skim milk.

As dlb pointed out in a comment, the creaminess and acid allows chemically risen baked goods to be fluffier with the same liquid and fat content as regular milk.

  • Hi @Sobachatina. Thanks for your historical insight. So is it normal protocol nowadays to add lemon to buttermilk if using in a leavening reaction with baking soda? Because I made some dough -- flour, baking soda, salt -- with the homemade buttermilk. Really wasn't interesting. Didn't smell good either.
    – wearashirt
    Commented Sep 8, 2017 at 4:12
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    Lemon is added to milk to acidify and thicken it as a quick replacement for buttermilk. Real buttermilk has much more interesting flavor. Lemon does not need to be added to real buttermilk- it is already plenty acidic to react with chemical leaveners. Commented Sep 8, 2017 at 15:27
  • Can I clarify: homemade, fresh buttermilk from whipping cream has enough acidity? Because I tasted my product and it was anything but acidic. It was like skim milk.
    – wearashirt
    Commented Sep 9, 2017 at 5:14
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    Ah yes. What you had was indeed skim milk. You forced the milk fat to coalesce and removed it. You are right. If you want to use that as buttermilk you'll have to acidify it. I would recommend adding some store bought buttermilk and letting it sit at room temperature for a day. It will be creamier and much more flavorful than simply adding lemon juice. Commented Sep 10, 2017 at 13:41

The role of buttermilk in most recipes is to provide acid into the reaction with baking soda to cause it to 'rise' more. The thickness helps the batter retain the air pockets that the acid + baking soda creates when heat is applied, resulting in a 'lighter fluffier' outcome.

(Although this question is not a duplicate of How does buttermilk affect a waffle recipe? the answer is the same: https://cooking.stackexchange.com/a/82981/6279)

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