Homemade Kefir

Name: Homemade Kefir (2-Ingredient Probiotic)
Prep time: 10 min
Total time: 24 h 10 min
Yield: 8 servings
Cuisine: Russian
Ingredients: 4 cups whole dairy milk (you want pasteurized milk, not ultra-pasteurized.); 1-2 tsp activated milk kefir grains

Jump to ingredients

Homemade kefir is a tangy, probiotic-rich fermented milk made with just whole milk and activated kefir grains, ready in 12-24 hours. It requires no cooking, minimal ingredients, and simple jar fermentation.

🌍Russian 🏷️Beverage 🏷️Breakfast 🏷️Healthy 🏷️Yogurt

Total

24h 10m

Servings

8

Recipe Source

View original recipe

From The View From Great Island

Ingredients

Check what you already have. We'll leave it off your shopping list.

4 cups whole dairy milk (you want pasteurized milk, not ultra-pasteurized.)
1-2 tsp activated milk kefir grains

2 Ingredients

CookOS may earn a commission from Instacart orders.

Powered by Instacart

Prices vary by store

^*Service fees apply. Instacart^® and the Instacart logo are registered trademarks of Maplebear Inc. d/b/a Instacart.

Instructions

1
Add the 1-2 tsp activated milk kefir grains to a clean dry quart-size glass jar.
2
Pour in the 4 cups whole dairy milk and gently stir.
3
Cover the jar with a cloth, coffee filter, or paper towel secured with the canning lid ring or a rubber band.
4
Let it ferment at room temperature (68–75°F) for 12 to 48 hours, depending on how tangy you like it. Leave it undisturbed, no need to shake or stir.
5
When it has thickened slightly and smells pleasantly sour, strain out the grains using a plastic or non-metal strainer.*
6
Store the finished kefir in the fridge and enjoy chilled.
7
Finished milk kefir will keep in the fridge for about 1 to 2 weeks.
8
You can reuse your strained kefir grains right away in a new batch of milk, or store them in the fridge for later in a small amount of milk.

Was this recipe helpful?

Tips & Notes

Pro tips

Use room-temperature pasteurized milk (not ultra-pasteurized) for reliable fermentation; grains activate faster in warmer kitchens (68–78°F).
Strain kefir through fine mesh to separate grains; reserve grains for the next batch and drink or refrigerate the finished kefir.
Taste after 12 hours and adjust fermentation time: shorter ferments yield creamier kefir, longer ferments create tangier results.
Keep kefir grains healthy by feeding them fresh milk every 12–24 hours; discard or compost any moldy batches and start fresh.

Substitutions

Whole dairy milk → non-dairy milk (oat, coconut, or cashew); fermentation may be slower and flavor less rich.
Pasteurized milk → raw milk (if available locally); may ferment faster but requires safe sourcing.

Storage & make-ahead

Store finished kefir in a sealed glass jar in the refrigerator for up to 2 weeks. Keep active grains in fresh milk in the fridge between batches.

Equipment

glass jar (1-quart or larger) · fine-mesh strainer · cloth or coffee filter (to cover jar during fermentation)

Common Questions

How long does homemade kefir take to ferment?

Kefir typically ferments in 12-24 hours at room temperature, depending on warmth and desired tanginess. Warmer environments ferment faster.

Can I use ultra-pasteurized milk for kefir?

No. Ultra-pasteurized milk lacks the nutrients kefir grains need and often fails to ferment properly. Use standard pasteurized whole milk instead.

What do I do with kefir grains between batches?

Store grains in fresh milk in the refrigerator for up to 2 weeks, or continuously ferment by straining and adding fresh milk every 12-24 hours.

Is homemade kefir safe to drink?

Yes, when made with clean equipment and fermented at room temperature. The fermentation process creates an acidic environment that prevents harmful bacteria.