Common Questions
Is this the same as “milk + vinegar” buttermilk?
No, and I say that with love for shortcuts. Milk + vinegar (or lemon) is a good substitute for baking in a pinch because it adds acidity, but it does not develop the same creamy thickness or cultured flavor. This recipe makes actual cultured buttermilk.
Is it safe to leave milk out at room temperature?
Yes, when you are using live cultured buttermilk as a starter, this is a controlled lactic fermentation (the friendly bacteria acidify the milk and help crowd out the bad actors). Keep everything clean, culture at normal room temp, and discard anything that smells foul, looks pink, turns fuzzy, or shows any mold.
What kind of milk works best?
Whole milk gives the creamiest result. 2 percent works too, just slightly thinner. Regular pasteurized milk tends to thicken the most reliably. Ultra-pasteurized (UHT) milk can culture, but it may take longer or end up a bit less thick depending on the brand.
What starter buttermilk should I buy?
Use plain cultured buttermilk from the store. Check the label for “cultured” and ideally “live active cultures.” Avoid flavored buttermilk or anything with lots of stabilizers if you can.
How do I know it is done?
It should look thicker, pour like a loose yogurt, and smell pleasantly tangy. A good visual cue: it should coat a spoon, and when you tilt the jar it often looks slightly set (not fully solid, but not plain milk either). If it smells foul, yeasty in a bad way, or looks pink, fuzzy, or moldy, toss it and start over.
Why did mine turn out thin?
Common causes: your kitchen was cool, your starter was old, or the milk was very low fat. Let it go longer (up to 36 hours), and next time use fresher starter and whole milk (and consider non-UHT milk for more reliable thickening).
Can I use homemade buttermilk as starter forever?
Usually you can keep it going for a while by always reserving some, but eventually the culture can weaken or drift. If it starts taking much longer to thicken or the flavor gets off, buy a fresh bottle and reboot the chain.
How do I scale this recipe up or down?
Easy rule of thumb: use about 1 tablespoon starter per 1 cup milk. This recipe uses 4 cups milk and 1/4 cup starter (that is 4 tablespoons), so it scales nicely.