Simply combine the milk and tablespoon of white vinegar or lemon in a bowl/ container and leave it to sit for around 10 minutes for the milk to 'sour'. Once rested, your homemade buttermilk replacement is ready to use.
How Long Does Buttermilk Last? I tend to only make enough for a specific recipe. However, if you find that you have lots of it leftover then it should be okay within the fridge for a few days. It will likely separate while in the fridge, just stir it thoroughly before using it again. It is also freezer-friendly for a few months, and can be handily poured into large ice-cube trays to portion it and simply defrost as needed. Just make sure to note how much liquid is in each ice-cube portion- to know how much to thaw.
The type of dairy milk you can use here is interchangeable- 1%, 2%, full fat. You can also use half and half.
Feel free to swap the milk out with your favorite Dairy-free, Lactose-free, or Vegan milk of choice- coconut milk, soy milk, almond milk, oat milk, etc.
While this homemade buttermilk substitute method works for probably 90% of recipes calling for traditional buttermilk, there may be times when it doesn't. In that case, you might want to try another cultured dairy product, such as:
Other Buttermilk Substitutes:Yogurt: Combine and mix 3/4 cup plain yogurt with 1/4 cup of milk or water, to thin. Sour cream: Mix 3/4 cup sour cream with 1/4 cup of milk or water to thin. Kefir: Use water or milk to thin your kefir until it reached the right consistency.