🥛 Kefir
Also known as: kephir
Fermented milk drink made with kefir grains, where bacteria and yeasts live together; under the Codex, at least 0.6% lactic acid.
Kefir is a fermented milk drink made from milk with kefir grains, in which lactic acid bacteria, acetic acid bacteria and yeasts live together. Under the Codex Alimentarius standard, kefir contains at least 2.7% milk protein, 0.6% lactic acid and 10⁴ CFU of yeasts in 1 g. It originates in the Caucasus.
Kefir grains resemble small cauliflower florets: hollow balls 2–9 mm across made of the polysaccharide kefiran, proteins and microbial cells. Up to 50 species of bacteria and yeasts have been found in them, and the mix depends on where the grains and the milk come from. The Codex describes a starter of Lactobacillus kefiri, species of Leuconostoc, Lactococcus and Acetobacter, plus yeasts that ferment lactose (Kluyveromyces marxianus) and yeasts that do not.
Yeasts give a light fizz and a little alcohol. In a lab experiment on whole milk, over 48 hours the pH fell from 6.70 to 4.99, producing 10.58 g/L of lactic acid and 5.17 g/L of ethanol. The Codex sets no alcohol limit for kefir.
Kefir or yogurt, buttermilk, kombucha? They are different drinks. Kefir is made from milk with a starter from kefir grains, where bacteria and yeasts live together, so it is lightly fizzy and has a little alcohol. Yogurt is fermented with only two bacteria, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Buttermilk does not need kefir grains: the Codex lets other fermented milks carry names set by national law or common usage. Kombucha is not a milk product, so the Codex definition of kefir does not apply to it.
On the shelf, look for the word “kefir” in the name: the Codex allows it only for a product that meets its requirements. Drinks with added water or flavours are labelled differently, and a flavoured product must name the flavour. Fat content is stated when leaving it out could mislead. Kefir sits in the chilled dairy aisle of supermarkets, corner shops and farmers’ markets. Live cultures are required only if the product was not heat-treated after fermentation.
Why it matters to you. In a small study of 15 adults with poor lactose digestion, plain kefir and plain yogurt reduced breath hydrogen (87 versus 224 ppm·h after milk), and the authors call for further research. The EU-permitted claim on lactose digestion applies only to live yogurt cultures. If kefir was heat-treated after fermentation, live cultures are not required. Check the label: the Codex allows the name “kefir” only for a product that meets its requirements, while a heat-treated one is called “heat treated fermented milk”.
Facts
| Acidity | at least 0.6% lactic acid (by mass) 1 |
|---|---|
| Legal basis | Codex Alimentarius, Standard for Fermented Milks, CXS 243-2003 1 |
| Raw material | milk and a starter from kefir grains: bacteria and yeasts 12 |
| Region | Caucasus 2 |
How it connects to milk
Links
- Made from which milk
- 🥛 Cow's milk
- Packed in
- 🍼 Bottle
- Made from
- 🥛 Milk
- How it is made
- 🔄 Fermentation
- Where it is made
- 🏭 Dairy plant
- Where it is stored or sold
- 🧊 Refrigerator
- What it contains
- 🧪 Lactic acid, 🧪 Lactose
- What affects it
- ❤️ Lactose intolerance, ❤️ Milk protein allergy
- Where it is traditional
- 🌍 Caucasus
- Which peoples make it
- 🧑🤝🧑 Karachays and Balkars
- Product type
- 🏺 Traditional dairy products
- Part of
- 🥣 Fermented milk products
- Similar and different
- 🧀 Soured milk, 🥣 Yogurt, 🧀 Buttermilk
- Wine and milk
- 🍷 Malolactic fermentation, 🍷 Yeast
Frequently asked questions
Is it true that kefir is the same as yogurt?
No. Yogurt is fermented with two bacteria, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, while kefir uses a starter from kefir grains with bacteria and yeasts. Under the Codex, kefir has at least 10⁴ CFU of yeasts in 1 g.
Is kefir dairy?
Yes. The Codex defines kefir as a fermented milk, a milk product made by fermenting milk with a starter from kefir grains. A drink fermented without milk is not covered by that definition.
Is kefir lactose free?
The page gives no lactose figure. In a study of 15 adults with poor lactose digestion, kefir improved it, and perceived flatulence after kefir and yogurt was 54–71% lower than after milk. It is a small study, not a treatment; if in doubt, talk to a doctor.
Does kefir contain alcohol?
Yes, a little: yeasts produce ethanol. In a study on whole milk it reached 5.17 g/L after 48 hours. The Codex sets no alcohol limit for kefir, so check the label.
How do I choose a good kefir?
Look for the name “kefir”: the Codex allows it only for a product with at least 2.7% milk protein, 0.6% lactic acid and 10⁴ CFU of yeasts in 1 g. A product heat-treated after fermentation is called “heat treated fermented milk” and need not contain live cultures.
Comparisons
Recipes
History
What to read next
- 🥛 Cow's milk — The most widespread milk in the world: versatile, inexpensive and the basis of almost all dairy products.
- 🧑🤝🧑 Karachays and Balkars — Related Turkic peoples of the North Caucasus mountain valleys near Mount Elbrus; they are credited with the origin of kefir.
- 🏺 Traditional dairy products — Products made for centuries to folk recipes: fermenting, cheesemaking, slow baking, drying. Tied to regions and peoples.
- 🧊 Refrigerator — Home storage of milk: no warmer than +4 °C.
- 🍼 Bottle — A milk bottle is a glass container, often one pint (568 ml), in which milk was delivered and sold.
Similar
🧀 Matsoni · 🍶 Ayran · 🥣 Viili · 🥣 Kashk · 🥛 Filmjölk · 🥣 Yogurt
ℹ️ Dairy products contain lactose and milk proteins: if you are lactose intolerant or allergic to milk protein, ask a doctor.
Sources
- Codex Alimentarius: Standard for Fermented Milks (CXS 243-2003)
- Nejati F. et al. A Big World in Small Grain: A Review of Natural Milk Kefir Starters. Microorganisms, 2020 (PMC)
- Hertzler S.R., Clancy S.M. Kefir improves lactose digestion and tolerance in adults with lactose maldigestion. J Am Diet Assoc, 2003 (PubMed)
- EUR-Lex: Commission Regulation (EU) No 432/2012 — permitted health claims (live yoghurt cultures)
- Production and Characterization of Kefir Beverages by Fermentation of Whole Milk with Milk or Water Kefir Grains. Foods, 2026 (PMC)