DO HOMEMADE BUTTERMILK SUBSTITUTIONS WORK?

NO! 

Despite widespread claims that adding lemon or vinegar to milk yields the same results as buttermilk, the simple chemical composition proves this false. Buttermilk alternatives have a higher pH value and do not react similarly with the baking soda in recipes. As a result, the overall outcome will have less volume and a less defined structure.

So, if there's one takeaway from this post, it's to make sure to use buttermilk in your recipes!