Making yoghurt at home is simpler than most people expect. The process has two variables that matter – temperature and starter culture – and once you understand why they matter, the rest is just following a straightforward sequence of steps. Homemade yoghurt is milder than commercial yoghurt (you control the fermentation time and therefore the acidity), contains more live cultures (commercial yoghurt is often heat-treated after fermentation), and costs a fraction of the commercial equivalent. It’s also one of the most satisfying things you can make in a kitchen because the transformation is genuinely remarkable: warm milk and a spoonful of culture become yoghurt overnight without any further intervention from you.
What You Need
1 litre of whole milk (full-fat UHT works, but fresh pasteurised gives a better result), 2 tablespoons of plain yoghurt with live cultures as your starter (use store-bought to start – any yoghurt with live cultures will work), a thermometer (a digital probe thermometer is best; a jam thermometer also works), a heavy-bottomed saucepan, a clean jar or container with a lid, and a way to maintain warmth for 6-8 hours (options below).
The Method
Heat the milk in a heavy saucepan over medium heat, stirring frequently to prevent scorching, until it reaches 85°C. Hold it at this temperature for 5 minutes – this denatures the whey proteins and produces a thicker, more cohesive yoghurt than milk heated only briefly. Remove from heat and allow to cool to 43-46°C (this is the key temperature range – the bacteria in the starter are active and multiplying between 40-46°C, but die above 50°C, so accuracy here is important).
Whisk the 2 tablespoons of starter yoghurt into a small amount of the warm milk to temper it, then stir this mixture into the rest of the milk. Pour into your clean jar or container and seal. Now keep it warm at around 43°C for 6-10 hours. Options: wrap the jar in a thick towel and place in a turned-off oven with just the light on; use a yoghurt maker (purpose-built and foolproof); place in a thermos flask; or use an Instant Pot on the yoghurt setting. A longer fermentation produces a more acidic yoghurt; shorter produces a milder result. Check at 6 hours – if it’s set (the jar tilts without sloshing), it’s done.
Straining for Thickness
Fresh homemade yoghurt is thinner than the commercial variety. To thicken it: pour into a colander lined with cheesecloth over a bowl and refrigerate for 1-4 hours. Strain for 1 hour for a texture similar to commercial yoghurt; 2-3 hours for Greek-style yoghurt; 4+ hours for labneh. The liquid that drains off is whey – keep it for bread, pancakes, or smoothies. Don’t discard it.
Saving Starter for the Next Batch
Reserve 2 tablespoons of your finished yoghurt in a separate sealed container before using the rest. This becomes the starter for your next batch. A continuous cycle of homemade yoghurt, where each batch seeds the next, can be maintained indefinitely. The culture does gradually drift in flavour and potency over time – if your yoghurt stops setting reliably after many cycles, buy a fresh commercial yoghurt to restart. Some people maintain the same culture for years; others refresh it every few months.
