How to make kefir (fruit or milk): simple recipe, time, mistakes to avoid

How to make kefir : mix kefir grains with a suitable liquid (sweetened water or milk), ferment for 12 to 48 hours at room temperature, then filter and keep refrigerated.

• Step-by-step recipes (fruit kefir and milk kefir)
• Clear indicators: time, temperature, quantities
• Troubleshooting chart (taste, bubbles, mold, grains)
• Safety and hygiene tips to avoid mishaps
• Ideas for use and storage

In practical terms, there are two main types: fruit kefir (a sparkling drink made from sweetened water) and milk kefir (similar to a drinkable yogurt). The "grains" are not interchangeable: water kefir grains ≠ milk kefir grains.

1) Before we begin: what are we talking about and what difference does it make?

Kefir is a fermentation process carried out by a community of microorganisms (bacteria and yeasts) living in "grains". In practice, this changes three things:

• the result varies depending on the temperature, the sugar (for fruit kefir) and the time ;
• simple hygiene is required (clean, without being sterile);
• You need to learn to read signals : bubbles, smell, acidity, texture.

To place this in a credible health context: fermented foods can contain live microorganisms and metabolites; the scientific literature on their effects varies greatly depending on the strain, dosage, and individual. General references: scientific source, scientific source.

2) Equipment and hygiene rules (simple, but non-negotiable)

• Glass jar (1 L ideal), clean and well rinsed
• colander (both work; avoid aluminum)
• Wooden/plastic/stainless steel spoon
• Fabric + elastic or lid placed loosely (gas)
• Bottle with mechanical closure (option for second fermentation, sparkling)

Rules: wash your hands, avoid dirty sponges, rinse the jar well, and throw away anything if there is mold (down, green/black stains, musty smell).

3) Fruit kefir (water kefir) recipe: step by step in 10 minutes

Ingredients (for 1 L)

• 20 to 40 g of fruit kefir grains
• 1 L of water (filtered or spring water; avoid heavily chlorinated water)
• 30 to 50 g of sugar (white or brown; the sugar mainly nourishes the grains)
• 1 dried fig or 2–3 raisins (optional but helps the starter)
• 1 slice of organic lemon (or a small piece of zest)

Steps

• 1. Dissolve the sugar in a little water, then top up to 1 L.
• 2. Add the grains, fig/raisins and lemon.
• 3. Cover (with a cloth) and let ferment for 24 to 48 hours at 20–25 °C.
• 4. When the fig rises to the surface (often) and it smells slightly acidic, filter it.
• 5. Chill (for a more stable and smoother drink).

In practical terms: the warmer it is, the faster it ferments. If you want less acidity, filter after 24 hours. For more fizz, do a second fermentation (section 5).

4) Milk kefir recipe: step by step (creamy texture)

Ingredients (for 500 ml to 1 L)

• 1 to 2 tablespoons of milk kefir grains
• 500 ml to 1 L of milk (cow, goat, sheep; UHT milk works, but some prefer non-UHT pasteurized)

Steps

• 1. Put the grains in a jar, add the milk.
• 2. Cover (with fabric) and leave for 18–24 hours at 20–24 °C.
• 3. When the mixture thickens and smells like yogurt, gently filter it.
• 4. Place the grains back in fresh milk to restart a cycle.

In practice, if you wait too long, the milk kefir may separate (whey + curds). This isn't necessarily a "failure": mix it, or drain it to make fresh cheese.

5) The second fermentation (F2): obtaining bubbles, without risk

The F2 is mainly used for fruit kefir: you bottle the filtered drink to increase the fizz and flavor it.

• Pour into a mechanical bottle leaving 3–4 cm of air.
• Add a little sugar (e.g., 1 tsp) or fruit (ginger, raspberry, mango).
• Leave for 12 to 24 hours at room temperature.
• Open by degassing over the sink (pressure possible), then refrigerate.

What this changes: the cold slows down fermentation and stabilizes pressure. If your kitchen is warm, reduce the duration of the second fermentation (F2).

6) Reference table: quantities, time, temperature (to avoid confusion)

7) How to know if it's successful (simple signals)

• Odor : tangy, slightly yeasty (no mold).
• Taste : sweet which diminishes, becoming more acidic over time.
• Appearance : fine bubbles (fruit kefir), thickening (milk kefir).
• Grains : they often multiply with regular cycles.

If you're a beginner, note down 3 things for each batch: room temperature, baking time, and amount of sugar. You'll progress very quickly.

8) Common mistakes (and quick fixes)

9) Who is it useful for (and precautions)

• Useful if : you are looking for a less sweet drink than sodas, fermented foods for everyday use, or a homemade alternative.
• Test with caution : if you have a very sensitive bowel (bloating), start with 50–100 ml/day and increase gradually.
• Seek medical advice : immunosuppression, heavy treatments, high-risk pregnancy, history of opportunistic infections. Recommendations vary depending on the situation.

For a cautious overview of probiotics and health: scientific source. For general guidelines on food safety and hygiene: scientific source.

10) How to drink it and use it (specifically)

• To drink : plain, with lemon/mint, or as a mocktail (kefir + sparkling water + fruit).
• With meals : a glass can replace a sugary drink.
• In the kitchen : milk kefir can be blended with fruit and flakes (smoothie), or drained into fresh cheese.

What this changes: if you are taking it for digestive comfort, regularity matters more than the quantity at once.

11) Storage, rest and maintenance of grains

• Filtered beverage : 2 to 5 days in the refrigerator (taste may change).
• Fruit seed break : in lightly sweetened water in the fridge, change once a week.
• Milk granule break : in milk in the fridge, change every 5–7 days.
• Freezing/drying : possible but may weaken; favor regular exchange with someone.

12) FAQ – how to make kefir?

What is the difference between fruit kefir and milk kefir?

The grains are different and cannot be replaced: fruit = sweetened water; milk = milk, fermented texture like drinkable yogurt.

Is sugar absolutely necessary for fruit kefir?

Yes: sugar feeds the fermentation. You can adjust the fermentation time for a less sweet drink at the end of fermentation.

How long should the fermentation process take to avoid having too much alcohol?

Leave for 24–48 hours in F1 and 12–24 hours in F2, then refrigerate. Longer/warmer periods may increase fermentation byproducts.

Can we use tap water?

Yes, but if it is very chlorinated, leave it open overnight or use filtered water.

Why does my bottle have too much pressure in F2?

F2 too long, room too warm, too much sugar/fruit. Reduce to 8–12 hours and “degas” 1–2 times.

What should I do if it smells bad?

A tangy/yeasty smell is normal. A musty, rotten smell or the presence of fuzz/stains = throw it away.

How much kefir should I drink per day?

Start small (50–100 ml), then increase as tolerated. Above all, listen to your symptoms (bloating, bowel movements).

Do the grains necessarily grow larger?

Often yes, but not always. Water too low in minerals, irregular cycles or too little sugar can slow growth.

To learn more about lifestyle and digestive comfort, see our digestion page. If you're also looking to manage stress (which often affects the gut), see our stress and anxiety page. And for a holistic approach, see our natural wellness page.