If you decide to keep buttermilk on hand, store it in the coldest part of your fridge, not the door. It stays fresh for about two weeks past the sell-by date, even a few days longer if it smells fine. Trust your nose—if it smells sharp but pleasant, it’s usable.
Use leftover buttermilk in unexpected places: marinade chicken for extra tenderness, stir it into mashed potatoes for a tangy fluff, or whisk it into salad dressings for a creamy, low-fat base. A little goes a long way toward elevating everyday meals.
What Milk Can Replace Buttermilk at Jeremy Tellez blog
And if the texture of store-bought buttermilk feels too thick for drinking, just give it a vigorous shake or whisk. You can also dilute it with a splash of water or milk to reach your preferred consistency. It’s forgiving.
