Homemade Greek Yogurt (Two Ingredients)

Name: Homemade Greek Yogurt (Two Ingredients)
Prep time: 25 min
Total time: 505 min
Ingredients: 1 liter milk (whole milk gives a thicker result than skimmed); 1 plain yogurt, with live cultures (about 2 tablespoons; check the label says live or active cultures)

Milk warmed to 46°C, stirred with a spoonful of live yoghurt and left overnight, then strained through cloth until it thickens. Two ingredients, almost no work, and the whey that drains off is worth keeping.

Total: 8 25

JUMP TO RECIPE

Milk and a spoonful of yoghurt. That is the entire ingredient list, and what turns one into the other is temperature and time.

46 degrees, and they are Celsius

The original recipe says to reach 46 degrees without saying which scale, which matters a great deal: 46°F is 8°C, cold enough that nothing will ever happen.

46°C is the temperature at which the cultures in the starter yoghurt multiply fastest. Above about 50°C they start dying; below 40°C they slow down and the milk may not set at all.

Without a thermometer, the finger test works and is what most people use: dip a clean finger in and it should be hot enough to be uncomfortable but not so hot you pull it straight out.

The starter has to be alive

Any plain yoghurt works as a starter provided it contains live cultures. The label will say live or active cultures. Some long-life yoghurts are pasteurised after fermenting, which kills exactly the bacteria you need, and those will not work no matter how careful you are with the temperature.

Two tablespoons is plenty for a litre of milk. More starter does not make it set faster; it just makes it more sour.

What makes it Greek

Straining. Ordinary yoghurt becomes Greek yoghurt by draining off the whey through cloth, which concentrates what is left.

How long you drain decides how thick it gets. Two hours gives a thick yoghurt; four gives something you can stand a spoon in; overnight gives something close to cream cheese. Do it in the fridge rather than on the counter.

Do not throw away the whey

The yellowish liquid that drains off is whey, and it is useful. It goes into bread dough in place of some of the water, into smoothies, and into the cooking water for rice or pulses.

Keep two spoonfuls of each batch of yoghurt to start the next one, and you never need to buy a starter again.

More things made from milk

Kumis — the Colombian fermented milk drink.
Strawberry yoghurt — the same method with fruit.
Homemade cheese — where milk goes next.
Colombian dairy — which cheese is which.

Greek Yogurt FAQ

What temperature does the milk need to be?

46°C, and they are Celsius. The original recipe gives the number without the scale, which is a problem because 46°F is 8°C and nothing will happen. Above 50°C the cultures start to die; below 40°C they may not set the milk at all.

How do I check without a thermometer?

Dip a clean finger into the milk. It should be hot enough to be uncomfortable but not so hot that you pull it straight out. This is how most people do it and it is accurate enough.

What yoghurt can I use as a starter?

Any plain yoghurt whose label says live or active cultures. Two tablespoons per litre of milk is plenty. Yoghurts pasteurised after fermenting will not work, because the process kills the bacteria you need.

What makes it Greek rather than ordinary yoghurt?

Straining. Draining the whey off through cloth concentrates what remains. Two hours gives thick yoghurt, four gives something very firm, and overnight gives something close to cream cheese.

What do I do with the whey?

Keep it. The yellowish liquid that drains off goes into bread dough in place of some of the water, into smoothies, or into the cooking water for rice and pulses.

📖 Recipe