The first batch of homemade yogurt I ever made was soup. Thin, watery, slightly sour soup. I’d overheated the milk and killed the bacteria before they could do their job. The second batch was perfect — thick enough to stand a spoon in, creamy, better than anything from the store.

Once you get the temperature right, it’s almost impossible to mess up.

You need exactly two things

Milk and a spoonful of yogurt with live cultures. That’s it. The yogurt is your starter — it contains the bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) that ferment the milk into yogurt. Buy a small container of plain yogurt — check the label for “live and active cultures.”

For Greek yogurt: after fermentation, strain through cheesecloth or a coffee filter for 2-4 hours in the fridge. The liquid that drains out is whey — save it for smoothies or bread baking.

Save 2 tablespoons of each batch as starter for the next one. You can keep this chain going indefinitely. I’m on batch 14 from the same original starter.