01Culture, incubate, chill

Cultured dairy products rely on beneficial bacteria (or, for kefir, a bacteria-yeast culture) fermenting milk at a specific temperature over several hours — a small amount of a previous batch can usually restart the next one.

02What you'll need

Fresh milk
A starter culture (a small amount of live yoghurt, a yoghurt culture sachet, or kefir grains)
A thermometer
A means of holding a consistent incubation temperature (a warm oven, an insulated container, or a yoghurt maker)

03Method

1. Heat milk to just below boiling, then cool to the culture's specified incubation temperature (usually around 40–45°C for yoghurt).
2. Stir in the starter culture thoroughly.
3. Hold at incubation temperature for several hours, undisturbed, until set.
4. Chill thoroughly before eating or further processing (straining for a thicker, Greek-style yoghurt).
5. Save a small amount of the finished batch as starter culture for the next one.

04Troubleshooting

Yoghurt doesn't set — incubation temperature too low, or the culture wasn't active/live; check both.
Runny texture — normal for some milk types; strain through cloth for a thicker result if desired.
Sour or off flavours developing over successive batches — culture can weaken or become contaminated after many generations; refresh with a new starter culture periodically.
Kefir grains not thriving — check they're getting fed regularly with fresh milk and aren't left too long between batches.

05Timing & maintenance

Best time

Any time milk is available; a very approachable year-round project.

Duration

6–12 hours incubation, depending on the culture and desired tartness.

Maintenance

If maintaining a continuous culture (like kefir grains), regular feeding with fresh milk.

Signs of success

A clean, set texture (for yoghurt) with a pleasant tang, no separation beyond a little natural whey.

06Tips & variations

Pairs well with

Milking Sheep & GoatsCheesemaking Basics

Common mistakes

Using a culture that's no longer active/liveDisturbing the milk during incubation, which can prevent a good set

Pro tip

Kefir is even more forgiving than yoghurt and ferments at room temperature — a good starting point if you don't want to manage a precise incubation temperature.

Yoghurt & Cultured Dairy