Kefir: The Fermented Drink With More Probiotics Than Yogurt
Kefir contains up to 61 strains of bacteria and yeast — far more than yogurt. Making it at home is surprisingly simple and costs almost nothing.
Yogurt typically contains 2–7 bacterial strains. Kefir contains up to 61 distinct strains of bacteria and yeast. That difference isn’t marketing — it’s been confirmed by culture analysis in multiple peer-reviewed studies and has real implications for gut diversity.
A 2021 randomized controlled trial in Cell (Wastyk et al.) compared high-fermented-food diets to high-fiber diets and found the fermented food group showed significantly greater increases in microbiome diversity, along with reductions in inflammatory markers. Kefir was one of the primary foods used.
The Two Kinds of Kefir
Milk kefir — made from dairy milk. Creamy, tangy, slightly effervescent. Contains lactose (though kefir grains ferment most of it, making it tolerable for many lactose-intolerant people).
Water kefir — made from sugar water. Lighter, less tangy, fully vegan. Slightly fewer probiotic strains than milk kefir, but still substantial.
This guide covers milk kefir. The process for water kefir is nearly identical but uses different grains.
What You Need
- 1 litre whole cow’s milk (or goat’s milk — both work)
- 1 tablespoon milk kefir grains
- A glass jar
- Cheesecloth or a fine mesh strainer
- That’s it.
How to Make Milk Kefir
- Place kefir grains in a clean glass jar.
- Pour milk over grains. The ratio doesn’t need to be precise — roughly 1 tbsp grains per 250–500ml milk.
- Cover with cheesecloth and a rubber band (not a sealed lid).
- Leave at room temperature (18–25°C / 65–77°F) for 18–24 hours.
- Stir or gently swirl once or twice during fermentation.
- When thick and pleasantly tart, strain through a fine mesh strainer or cheesecloth.
- The liquid that passes through is your kefir. The grains stay in the strainer.
- Rinse grains with non-chlorinated water and place back in the jar for the next batch.
What Changes With Time and Temperature
| Condition | Result |
|---|---|
| Warmer temp / longer time | More tart, thicker, more effervescent |
| Cooler temp / shorter time | Milder, thinner |
| Too long (>36h) | Over-fermented, very sour, separates into curds/whey |
If you need to pause: put the grains in milk in the fridge. Cold dramatically slows fermentation — grains can rest for 1–2 weeks this way.
Nutritional Profile (per 250ml)
| Nutrient | Amount |
|---|---|
| Protein | 8–9g |
| Calcium | ~300mg (30% DV) |
| Vitamin B12 | ~0.9µg (37% DV) |
| Probiotics | 10⁷–10⁹ CFU/ml |
| Lactose | ~30–40% less than plain milk |
Using Your Kefir
- Drink plain (chilled is best)
- Blend into smoothies
- Replace buttermilk in pancakes or baking
- Make kefir cheese: strain overnight through cheesecloth in the fridge
Grains Multiply — Share Them
Healthy grains grow with every batch. After a few weeks you’ll have more than you need. Rinse the excess and give them to friends, or freeze them in milk for long-term storage.
References: Wastyk et al. (2021) Gut-microbiota-targeted diets modulate human immune status. Cell 184(16). Bourrie et al. (2016) The Microbiota and Health Promoting Characteristics of the Fermented Beverage Kefir. Frontiers in Microbiology.