Short answer: yogurt and kefir are both fermented milk, but they're made with different cultures. Yogurt is made with two bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus, fermented warm for a few hours, and it sets into a spoonable, tangy food. Kefir is made with kefir grains, a mix of many bacteria and yeasts, fermented at room temperature for about a day, and it's thinner, drinkable and slightly fizzy. Both are easy to make at home.
Yogurt vs kefir at a glance
- Cultures: yogurt uses two bacteria; kefir uses a community of many bacteria and yeasts.
- Starter: yogurt starts from a starter powder or a spoonful of yogurt; kefir starts from kefir "grains" (small, cauliflower-like clusters of the cultures) or a kefir starter powder.
- Temperature: yogurt ferments warm, around 110°F (43°C); kefir ferments at room temperature.
- Time: yogurt with Natren Yogurt Starter sets in about 4 to 8 hours; kefir usually takes about 12 to 24 hours.
- Texture: yogurt is thick and spoonable; kefir is pourable, like a drinkable yogurt, and often slightly effervescent from the yeasts.
- Taste: yogurt is clean and tangy; kefir is tangy and a little yeasty, sometimes with a faint fizz.
How yogurt is made
Yogurt is made by heating milk, cooling it to about 110°F, adding the two yogurt cultures and keeping it warm until it thickens. The cultures turn lactose, the sugar in milk, into lactic acid, which sets the milk and gives yogurt its tang. That pair of cultures is what makes yogurt, from traditional Bulgarian yogurt to the thick, strained Greek style.
With Natren Yogurt Starter, a culture of L. bulgaricus LB-51 and S. thermophilus BC 122, 1 to 2 level teaspoons make 2 quarts of yogurt, and one bottle makes up to 30 quarts. See our full guide to making yogurt at home, or use the Instant Pot method.
How kefir is made
Kefir grains are added to milk at room temperature and left, loosely covered, for about a day. The bacteria and yeasts in the grains ferment the milk, thickening it slightly and adding a gentle fizz. The grains are then strained out and added to fresh milk to start the next batch, and they keep growing as long as they're fed. The yeasts also produce a little carbon dioxide and a trace of alcohol, which is part of kefir's distinctive taste.
Which should you make?
- Make yogurt if you want something thick and spoonable for breakfast bowls, cooking, dips and sauces, or to strain into Greek yogurt or yogurt cheese.
- Make kefir if you'd rather drink it, add it to smoothies or enjoy a tangier, fizzier taste.
- Make both: they use the same milk and simple kitchen tools, but keep them apart. Yogurt cultures and kefir grains are different starters, and they shouldn't be mixed.
Cooking with yogurt and kefir
- Both work in smoothies, overnight oats and salad dressings.
- Yogurt is the better choice for dips such as tzatziki, marinades and anywhere you want thickness.
- Kefir can stand in for buttermilk in pancakes, biscuits and quick breads.
- For ideas, try our green yogurt recipes.
FAQ
Can I make kefir with yogurt starter?
No. Yogurt starter contains the two yogurt cultures, which need warmth and make yogurt. Kefir needs kefir grains or a kefir starter. Natren Yogurt Starter is for yogurt.
Can I make yogurt with kefir grains?
No. Kefir grains make kefir. For yogurt, use a yogurt starter with L. bulgaricus and S. thermophilus.
Is kefir just runny yogurt?
No. It's a different fermented milk, made with different cultures, including yeasts, which give it its fizz and slightly different taste.
Can I make either one dairy-free?
Natren's yogurt directions mention soy milk and goat's milk as well as cow's milk. Results with non-dairy milks vary, and some need a thickener to set. Kefir is also made with non-dairy milks and coconut water, with mixed results.
How should I store homemade yogurt and kefir?
Both go in the refrigerator, covered. Both get more tart over time. Keep your Yogurt Starter bottle refrigerated too.
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