Yogurt is milk fermented by bacteria that turn lactose into lactic acid, which thickens the milk and gives it its tang. Making it at home takes a few minutes of work and some waiting, and costs much less than buying it.
What you need
- Milk: whole milk gives the creamiest result; low-fat works but is thinner. Ultra-pasteurized milk also works. Plant milks need added thickeners and are trickier.
- Starter: 2 to 3 tablespoons of plain yogurt with live and active cultures, or a powdered yogurt starter.
- A way to keep it warm: an oven with the light on, an Instant Pot with a yogurt setting, a yogurt maker, or a cooler with warm water.
- A thermometer helps a lot.
Step by step
- Heat the milk to about 180°F (82°C), stirring so it does not scorch. Hold it there for a few minutes. This changes the milk proteins so the yogurt sets thicker.
- Cool it to about 110 to 115°F (43 to 46°C), warm but not hot to the touch. A sink of cold water speeds this up. Too hot will kill the cultures.
- Add the starter: whisk the yogurt with a cup of the warm milk, then stir it back into the rest.
- Incubate at about 110°F, without stirring, for 4 to 12 hours. Shorter gives a milder yogurt; longer gives a thicker, tangier one.
- Chill for several hours. It firms up further in the fridge.
Greek yogurt and labneh
Pour yogurt into a strainer lined with cheesecloth or a coffee filter, set over a bowl in the fridge, and let it drain for 1 to 4 hours for Greek-style yogurt, or overnight for a spreadable labneh. The liquid (whey) can be used in baking or smoothies.
Troubleshooting
- Runny yogurt: temperature too low or too high, a weak starter, or not enough time. Try longer incubation or a fresh starter.
- Too sour: shorten the incubation.
- Grainy texture: milk heated too quickly or starter not mixed in well.
- Strange colors, fuzzy mold or off smells: throw it out and start again with clean equipment.
Keep the cycle going
Save a few tablespoons from each batch to start the next one. After several generations, the culture can weaken; start again with fresh store-bought yogurt.
Storage
Homemade yogurt keeps about 1 to 2 weeks in the fridge in a clean, covered jar.
Fermented foods like yogurt are discussed in the best foods for gut health. If you enjoy fermenting milk, try making simple cheese at home.
