Buttermilk is an acidic ingredient that softens the texture of baked goods while adding body and a subtle, sour tang. Buttermilk helps quick breads rise and adds only a negligible amount of fat. While true buttermilk is the result of bacteria growing on the cream leftover from churned butter, plant-based replacements are simple enough to make and do a solid job replicating the principles of the dairy-based original.
Bakers have long utilized the classic kitchen swap for buttermilk of combining regular milk with an acid such as lemon juice. The method is the same with nondairy milk. Combine a ratio of one cup nondairy milk (thicker, plant-based milks like oat or soy are most successful) to one tablespoon acid (apple cider vinegar, lemon juice, or white vinegar). Whisk the two together and let sit for five to 10 minutes before using in your recipe.
Leftover plant-based buttermilk will keep in the fridge for up to four days or in the freezer for three months.