Ever felt like making a delicious dessert only to find that you have all the ingredients except buttermilk? I have had this problem frequently in the past, especially since buttermilk has an expiry date similar to milk but has a much lower turnover rate in my fridge compared to milk. To complicate matters, buttermilk is available in only one liter or half liter sizes, and most of the time I don’t use up all the buttermilk before its expiry date.
I’m glad to share with you a solution to all these ordeals pertaining to buttermilk. I learned how to make homemade buttermilk using the milk currently in my fridge. The formula is simple:
Place 2 1/2 tsp lemon juice in a glass measuring cup and add enough milk up to 1 cup. Stir and let the mixture stand for 5 minutes before using. And voilà. No more wasting unused buttermilk since you can make only the quantity you need! Any level of fat content for the milk can be used (whole milk, 1%, 2%, or skim milk), but usually whole milk is used for baking.
I tried this homemade buttermilk and it works well for buttermilk pancakes, and chocolate cakes. I don’t buy buttermilk anymore for my baking; it’s easier and less wasteful to just make my own buttermilk. I found that it works just as well and only takes 5 minutes!
How does it work? Buttermilk is just sour milk, which was made sour by increasing its acidity. Commercially, the acidity is from adding bacteria that produce lactic acid for fermenting the lactose sugar in milk. This type of buttermilk is more specifically known as cultured buttermilk. In this formula, we are increasing the acidity by adding citric acid from the lemon juice to produce the type of buttermilk known as acidified buttermilk. In both buttermilk types, when the level of acidity is increased in the milk, the milk protein casein will eventually precipitate. This precipitation is what causes the curdling and thus thickening of milk.