Fermented milk

Also called A38, A-38, A-38 surmælk.

A-38 is a Danish soured milk that Arla says has been part of Danish food culture since 1938. Milk of 0.5–3.5 % fat is high-pasteurised and soured with Lactobacillus acidophilus into a mild product that Danish Wikipedia calls a form of yoghurt or ymer. The name joins the year 1938 to the letter A, which first stood for the cooperative dairy and is now linked with acidophilus.

Codex rule for acidophilus milk (a comparison, not a figure for A-38)

Codex sets at least 0.6 % lactic acid and at least 10^7 cfu/g of the starter culture to the date of minimum durability.

1. High-pasteurise the milk
2. Sour with L. acidophilus

Safety: The milk is high-pasteurised before souring.

• Codex Alimentarius, Standard for Fermented Milks, CXS 243-2003 (rev. 2008, 2010), sections 2.1 and 3.3 (acidophilus milk)
• Arla Foods Denmark, Arla A38 product page "Siden 1938" (web.archive.org copy of 15 June 2018)
• Arla Foods Denmark, Arla Cultura product page (A38 Naturel 1.5 %), read 2026-10
• da.wikipedia, A-38

Also called amateregua.

Amateregua is a Burundian milk product made at household level, listed with urubu and amavuta in a 2009 review.

1. Ferment the milk into urubu

• Aloys N., Angeline N. 2009, Traditional fermented foods and beverages in Burundi, Food Research International 42:588–594 (abstract)
• Karenzi E. et al. 2013, Kivuguto traditional fermented milk and the dairy industry in Rwanda. A review, Biotechnologie, Agronomie, Société et Environnement 17(2) (urubu is similar to kivuguto; its microbes have not been studied)

Also called айран.

Ayran in Xinjiang is a Kazakh artisanal fermented milk that sets to a curd whose hardness varies from sample to sample. The drink that Caucasian and Turkish cooks call ayran is a different product, katyk or suzma diluted with water, called shalap in Kazakhstan.

1. Sour the milk

• Kuerman M., Wang R., Zhou Y. et al. 2023, Metagenomic insights into bacterial communities and functional genes associated with texture characteristics of Kazakh artisanal fermented milk Ayran in Xinjiang, China, Food Research International, doi:10.1016/j.foodres.2022.112414 (abstract)
• Kochetkova T.V., Grabarnik I.P., Klyukina A.A. et al. 2022, Microbial communities of artisanal fermented milk products from Russia, Microorganisms 10(11):2140
• Wikipedia (ru), Кисломолочные продукты (outline only)

Also called বর্ণির ধুছনির দই, ধুছনির দই, Dhuchnir doi of Barni.

Bornir dhuchnir doi is a firm curd from Borni in Moulvibazar, Bangladesh, set in a small bamboo-and-cane basket (dhuchni) whose holes are sealed with a flour paste. It is made mainly from thick buffalo milk with nothing added, and sold in its basket.

1. Boil the milk down3–4 h
2. Seal a bamboo-cane basket with flour paste
3. Set the curd in the basket

Safety: Prothom Alo says the milk is bought fresh each day from local cattle and buffalo owners, and bn.wikipedia says it is boiled down for 3–4 hours before the curd is set. The milk is poured into a basket whose holes are sealed with a flour paste. The FDA says processing grain into flour does not kill harmful bacteria and that cooking is the only way to be sure. The sources do not say whether the paste is cooked.

• Akmal Hossain, স্বাদে ভিন্ন মৌলভীবাজারের 'বর্নির ধুছনির দই', Prothom Alo, 5 Nov 2023
• M.A. Hamid, মৌলভীবাজারে মাসে ৫-৬ লাখ টাকার মহিষের দই বিক্রি, Ekhon TV, 4 May 2024
• bn.wikipedia, বর্ণির ধুছনির দই; en.wikipedia, Bornir Dhuchnir Doi
• US Food and Drug Administration, Handling Flour Safely, What You Need to Know

Also called boruga.

Boruga is a sweetened sour milk from the Dominican Republic. Raw whole cow's milk is left unheated to sour on its own, then sugar is added at 13 % of the milk. It is a yellowish, lumpy, semi-fluid drink sold in plastic containers.

1. Leave raw whole milk to sour
2. Sweeten, pack and keep cold

Safety: Made from raw, unheated milk with a spontaneous fermentation; FAO gives a keeping time of up to 10 days at 4 °C. Raw milk can carry E. coli O157:H7, Salmonella, Campylobacter jejuni and Listeria monocytogenes, and the FDA says children are more vulnerable to these pathogens. The FDA says pasteurisation effectively kills raw milk pathogens. This method relies on the raw milk's own bacteria, and no source we read tests it with pasteurised milk.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II.3.1 (Boruga, Dominican Republic)
• US Food and Drug Administration, Raw Milk Misconceptions and the Danger of Raw Milk Consumption

Also called Bulgarian buttermilk.

Bulgarian buttermilk is a cultured milk sold in the United States. The US standard for cultured milk (21 CFR 131.112), which does not name this product, requires the milk to be pasteurised before the culture goes in and the finished milk to reach at least 0.5 % titratable acidity as lactic acid.

1. Pasteurise the milk
2. Culture the milk

Safety: The milk is pasteurised before culturing, as US rules require.

• US Code of Federal Regulations, 21 CFR 131.112 Cultured milk (covers all US cultured milks, not Bulgarian buttermilk by name)

Also called чалап, шалап, чалоп, shalap, chalop.

Chalap is a cold, sour drink made by rubbing a thick fermented milk, suzma or ayran, with a little water until smooth and then thinning it with much more water. It has no fermentation of its own, so it is a boundary entry, a drink mixed from a ferment. Kyrgyz cookbooks give one part suzma to ten parts water.

1. Take the fermented milk base
2. Rub with a little water until smooth
3. Thin with the rest of the water and salt
4. Serve cold, before the protein settles

Safety: The recipes we read mix the soured base with water or whey, and none heats the drink afterwards, so use a sound base and clean, safe water, and keep it cold.

• Batkibekova M.B., Musulmanova M.M. et al., Kyrgyz patent KG 736 C1 (2005), Fermented milk drink and composition for its stabilisation (citing Borubaev T., Kirgizskaya kukhnya, Frunze 1982, p. 157)
• Togorokbaev D.T., Kyrgyz patent KG 1084 C1 (2008), Fermented milk drink (citing Ibraimova S.Sh., Sovremennaya kirgizskaya kukhnya, Frunze 1989, p. 179)
• ru.wikipedia, Чалап (citing Pokhlebkin 1983, 1988; Massaget.kz 2020)

Also called chambiko, Malawi sour milk.

Chambiko is Malawi's sour milk. Traditionally raw milk sours for three to four days in a covered calabash or clay pot, and whey is drained off each day while fresh milk is added, until the vessel is full of thick curd. A factory chambiko is now sold in sachets.

1. Leave raw milk to sour in a covered vessel3–4 days
2. Drain whey daily and top up with fresh milk7 days

Safety: The traditional form is made from raw milk and its quality varies. The milk is not heated and sours for 3 to 4 days at room temperature. CDC says raw milk and products made from it can expose people to Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella. It says children under 5, adults over 65, pregnant women and people with weak immune systems are at higher risk of serious illness.

• FAO 1990, The technology of traditional milk products in developing countries, section II "Acidified milks", group 1.4
• Schutte L.M. 2013, Isolation and identification of the microbial consortium present in fermented milks from Sub-Saharan Africa, MSc thesis, Stellenbosch University
• US Centers for Disease Control and Prevention, Raw Milk (31 January 2025)

Also called чапамо ловсо (Erzya), шапама лофца (Moksha), шапама ловца (Moksha, as spelled by Natsionalny aktsent), shapama loftsa, Mordovian sour milk.

Chapamo lovso is the thick sour milk of Mordvin cooking. Whole milk is boiled, cooled, seeded with a starter, usually sour cream, and left in a warm place until it thickens, then chilled and served in small pots; it was drunk with pachat pancakes. No source gives its times or temperatures.

1. Boil and cool the milk
2. Add sour cream and keep warm until thick
3. Chill and serve in the pots

Safety: The milk is boiled before it is seeded.

• ru.wikipedia, Чапамо ловсо (citing Национальная библиотека Республики Татарстан, Мордовская кухня, 2018; nazaccent.ru; e-mordovia.ru 2018; Культура питания, Minsk 1993, p. 186)
• Национальный акцент, Путешествие в мир мордовской кухни (both names; drunk with pancakes)

Also called bainne clábair, bonnyclabber, clabbered milk.

Clabber is raw milk left to sour on its own until it sets into a thick, solid curd. It was eaten with a spoon, beaten with brown sugar, and used as a leavener for batter cakes before baking powder. It needs raw milk, because the souring bacteria come from the milk itself.

1. Leave raw milk to sour
2. Eat it, or bake with it

Safety: Clabber is raw milk eaten without heating after it sours. CDC says raw milk can carry Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella, and that children under 5, adults over 65, pregnant women and people with weakened immune systems are at higher risk of serious illness. Pasteurised milk does not clabber reliably, because pasteurisation kills the bacteria needed.

• Wikipedia, Clabber (food)
• Foods of England, Clabber or Clauber (quoting the Hull Daily Mail, 15 August 1917, and The Encyclopedia of Practical Cookery, 1891)
• US Centers for Disease Control and Prevention, Raw Milk (31 January 2025)

Also called dahee, dahi (Indo-Guyanese), Guyanese curd.

Whole cow milk is brought to the boil for several minutes, stirred with some dahee from the last batch and left for 5 to 8 hours until it sets. It is the Indian dahi, brought to Guyana by indentured labourers from India.

1. Boil the milkHeated to the boiling point for several minutes
2. Stir in old dahee and let it set5–8 h
3. Keep it cold

Safety: The milk is boiled before setting and the dahee keeps only about two days in a fridge.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II "Acidified milks" (Dahee, Guyana; Dahi, India and Myanmar)

Also called ဒိန်ချဉ်.

Dein chin is the Burmese name for dahi, the set curd of South Asia. Milk is boiled, cooled to body warmth, seeded with a little of the previous day's curd and left overnight to sour and set. A new line without old curd is started in Myanmar with fresh lime juice, which takes about 20 hours to coagulate the milk.

1. Boil the milk and cool it to body warmth
2. Add the old curd
3. Leave to setLeft overnight to sour and set

Safety: The milk is boiled before seeding.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II.2.3 (Dahi; Union of Myanmar)
• Wiktionary, ဒိန်ချဉ် (milk curd, yogurt)

Also called эремсек, эремчек, eremchek, kyzyl eremsek (red form).

Soured or freshly cultured milk with a little ayran, katyk or buttermilk is brought to the boil so that curd separates, and the curd is drained in a canvas bag. For a keeping form the curd is boiled down until all its water is gone, giving a reddish, sweetened dry curd. It is a boundary entry, an acid-and-heat curd made from fermented milk.

Boundary

An acid-heat curd made from fermented milk, on the cheese boundary like irimshik

1. Sour the milk with a starter
2. Bring to the boil
3. Drain the curd
4. Boil the curd dry (dry eremsek)

Safety: The dry form is boiled until its water has evaporated, so that it can be kept for a long time.

• Wikipedia (ru), Эремсек (summarises Migranova E.V., Bashkir Encyclopedia, Ufa)

Also called filmjölk, fil, fil, surmjölk, kulturmelk (Norway).

Filmjölk is Swedish soured milk, made with mesophilic lactic bacteria that work at room temperature. Milk with about 3 % fat is soured for about a day at 20–25 °C until it thickens to a mild, slightly buttery, drinkable curd near pH 4.5. It is eaten with a spoon, often with cereal.

1. Heat-treat and cool the milk
2. Add the culture
3. Sour at room temperature12–36 h · 20–25 °C
4. Chill4 °C

Safety: Made from heat-treated milk and kept refrigerated.

• Mechanistic insights into probiotic properties of lactic acid bacteria associated with ethnic fermented dairy products, Frontiers in Microbiology 2019, 10:502, doi:10.3389/fmicb.2019.00502 (filmjölk and långfil dominated by mesophilic lactococci)
• Arla Foods Sweden 2023, Arla Pro snabbguide till våra syrade mejeriprodukter (quick guide to fermented dairy products)
• Discover Real Food in Texas, How to ferment filmjölk (home guide; 20–25 °C, 12–36 h)
• Wikipedia, Filmjölk (cultures, fat levels and dates, citing Arla and other Swedish dairies)

Also called garoor.

Garoor is a Somali sour buttermilk. Raw, unheated cow's milk is churned, the butter taken off, and the buttermilk poured into a container smoked with cugid wood, where it sours on its own in about 3 hours. It keeps for up to 48 hours.

1. Churn the raw milk and take off the butter
2. Pour the buttermilk into a smoked container
3. Leave to sour3 h

Safety: Made from raw milk that is never heated, with a very short souring; FAO gives a keeping time of up to 48 hours and no storage temperature. CDC says raw milk can carry Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella. It says children under 5, adults over 65, pregnant women and people with weak immunity are at higher risk of serious illness.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II.1.3 (Arrera, Garoor, Non maï yami)
• US Centers for Disease Control and Prevention, Raw Milk (31 January 2025)

Also called iria ri matii, iria imata (FAO 1990 spelling, identification inferred), iria imata, Meru fermented milk.

Iria ri matii is the Meru sour milk of Kenya, made in a gourd whose inside is coated with charcoal from Olea europaea ssp. africana. Mureithi and den Biggelaar call the wood-smoke flavour and aroma an essential characteristic of the product.

FAO group value, not specific to this milk

FAO lists "iria imata" (taken here to be the same milk, from the similar spelling) in a group of African acidified milks. For the group it gives usually 24–48 h in a covered container, and room temperature that varies from 22 °C in Kenya to 35 °C in northern Benin (FAO 1990).

1. Line the gourd with Olea charcoal
2. Fill the gourd with milk and leave it covered

Safety: Boiling the milk first removes most raw-milk risks; charcoal and smoke reduce moulds but do not replace boiling.

• Mureithi W., den Biggelaar C. 2000, Management of trees used in mursik (fermented milk) production in Trans-Nzoia District, Kenya, Journal of Ethnobiology 20(1):75–91
• FAO 1990, The technology of traditional milk products in developing countries, section II "Acidified milks", group 1.1

Also called исгэлэн тараг, ᠢᠰᠬᠦᠯᠡᠩ ᠲᠠᠷᠠᠭ, isgelen tarag, Mongolian 'kefir'.

Boiled cow or yak milk, often the skim left after making urum cream, is seeded with culture from the last batch and stirred with a wooden plunger like airag. Lactic bacteria sour it and yeasts make it fizzy and lightly alcoholic in about a day.

1. Boil the milk (often after skimming off urum)
2. Cool to hand temperature and add old culture
3. Ferment with regular stirring24 h

Safety: Made from boiled milk and fermented by a culture of Lactobacillus bacteria and yeast. A recipe page puts its alcohol at about 2 %.

• Uchida K., Hirata M., Motoshima H., Urashima T. and Arai I. 2007, Microbiota of 'airag', 'tarag' and other kinds of fermented dairy products from nomad in Mongolia, Animal Science Journal 78:650–658 (abstract)
• Mongolfood.info, Isgelen Tarag – Исгэлэн Тараг (recipe page)
• Wikipedia, Isgelen tarag (outline only)

Also called كامخ رجل, countertop cheese.

Kamakh rijal is a salted milk relish from the 10th-century Arabic Book of Dishes. Sour milk, fresh milk and salt are put in a dried gourd shell in the hot sun in June, fresh milk is stirred in each morning until August, and the covered gourd ripens until October into a pungent spread. The steps here follow a translated recipe quoted by a modern recreator; no study has examined it.

1. Mix sour milk, fresh milk and salt in the gourd
2. Add fresh milk each morning
3. Cover and ripen in the sun

Safety: The medieval recipe keeps milk warm in the sun for months, adds fresh milk each morning and has no heating step. A modern blogger who made it credits the salt and the yogurt's bacteria with keeping off bad microbes, but no study we read tests the method. Raw milk can carry germs such as Campylobacter, E. coli, Listeria and Salmonella (CDC). Do not copy this at home, with raw or pasteurised milk.

• Pass the Flamingo blog, Kamakh rijal (countertop cheese), 2017 (quotes the Book of Dishes recipe and Charles Perry's method)
• Perry C. 1999, More rotted barley, Petits Propos Culinaires 61:42–43 (on kamakh ahmar; abstract page only)
• Perry C. 2006, Cooking with the Caliphs, Saudi Aramco World 57(4) (kamakh condiments)
• US Centers for Disease Control and Prevention, Raw milk

Also called kokkelipiimä, kokkeli, Eastern Finnish lumpy soured milk.

Kokkelipiimä is an eastern Finnish soured-milk drink with soft lumps of curd in it. Skimmed milk is left warm until it sets into a firm, whey-free curd (kokkeli), which is kept in water and later stirred into piimä or milk.

1. Leave skimmed milk warm until it sets2 days
2. Lift the curd into water and keep cool
3. Stir the kokkeli into piimä

Safety: The milk sets by itself through lactic bacteria. The curd is kept in water in a cool place, and the water is changed when more whey comes out of it (fi.wikipedia).

• fi.wikipedia, Kokkelipiimä (citing Sadeniemi M. (ed.), Nykysuomen sanakirja 2, WSOY 1996, p. 445)
• fi.wikipedia, Piimä
• Elävä perintö wiki, Kalakukko tradition

Also called күөрчэх, кёрчех, Yakut whipped cream.

Küörchekh is a Yakut dish of sour cream or cream whipped with berries and sugar. It is a boundary entry; only the sour cream in it is fermented, and the dish itself is whipped, not fermented.

Boundary

Mostly a whipped dessert; only the sour cream in it is fermented

1. Whip the cream or sour cream
2. Fold in berries and sugar

• ru.wikipedia, Якутская кухня (кёрчех, күөрчэх, whipped cream; sour cream or cream with berries and sugar)

Also called кымыс, көөнньүү кымыс, көйүүргэн, Yakut kumys, kenyu kumys (strong), koiyurgen.

Kymys is the Sakha (Yakut) name for koumiss, fermented mare's milk, the national drink of Yakutia. A stronger form is called köönnüü kymys or köiüürgen, and there are named variants such as kymys with melted butter.

1. Take fresh mare milk
2. Ferment

Safety: Codex sets minimum acidity (0.7 % lactic acid), ethanol (0.5 % vol) and live-culture counts (starter 10⁷ cfu/g, yeasts 10⁴ cfu/g) for kumys in general.

• Codex Alimentarius, Standard for Fermented Milks CXS 243-2003 (revised 2008, 2010), sections 2.1 and 3.3 (kumys in general)
• Danilov I.A. 2019, Номинации молочных продуктов (Yakut dairy product names), Lomonosov-2019 conference abstract, North-Eastern Federal University
• ru.wikipedia, Якутская кухня (names only)

Also called långfil, long fil, ropy milk, tätmjölk (when butterwort-started).

Långfil is the Swedish "long" soured milk, with a long, almost elastic texture. Wikipedia says it is filmjölk made with fil culture plus Lactococcus lactis subsp. lactis var. longi, a strain that makes long chains of polysaccharide.

1. Stir the culture into the milk
2. Leave to set

Safety: Mesophilic soured milk made from pasteurised milk; keep it cold once set.

• Toba T., Kotani T., Adachi S. 1991, Capsular polysaccharide of a slime-forming Lactococcus lactis ssp. cremoris LAPT 3001 isolated from Swedish fermented milk 'långfil', International Journal of Food Microbiology 12(2–3):167–171 (abstract)
• Rampanti G. et al. 2024, Technological and enzymatic characterization of autochthonous lactic acid bacteria isolated from viili natural starters, Foods 13:1115 (related Nordic ropy milk)
• Wikipedia, Filmjölk (history and the culture listed for långfil)

Also called 老北京酸奶, 酸奶, 酸乳, Beijing ceramic-jar yogurt.

Lao Beijing suannai is sweetened milk set as a yoghurt in small jars and drunk through a straw. Under China's national standard GB 19302-2025 a product called 酸乳 must be fermented with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus; sweetened kinds fall under flavoured fermented milk, with at least 60.0 °T acidity.

1. Sweeten and heat the milk
2. Add the starter, fill the jars and set
3. Chill

• GB 19302-2025, National food safety standard, Fermented milk (食品安全国家标准 发酵乳), issued 16 March 2025, in force 16 September 2025; copy on the Fuzhou market regulator's site
• Jia Sixie, Qimin Yaoshu (6th century), vol. 6, ch. 57, 作酪法; Chinese text on Wikisource

Also called mascarpìn.

Cow and goat whey from cheesemaking, with a little goat milk, is heated and set with rock alum, vinegar or soured whey, and the rising flakes are drained in a stocking-shaped cloth. It is a boundary entry, set by acid and heat, not by microbes; small fresh forms are eaten soon, large ones are aged about 2 months.

Rind

Bloomy on aged forms

Size

Elongated truncated cone of 3.0–5.0 kg, or ovoid of 0.150 kg

Boundary

Set by acid and heat, not by microbes

1. Mix whey and goat milk
2. Heat and add acid60–85 °C
3. Drain in a stocking-shaped cloth24 h
4. Wrap and ripen2 months · 2–4 °C

Safety: The whey is heated to 85 °C. Fresh mascarpin must be eaten within a very short time; the aged form is kept about 2 months, at 2–4 °C in a controlled cold room or in cool, damp cellars (crotti). The sheet says salt has recently been added to keep it longer, and that forms lightly salted and smoked by the hearth can keep for years. Rock alum is one of the souring agents the sheet lists. ONAF's sheet for mascherpa d'alpe, a related Lombard whey cheese, says the use of rock alum was banned because of its toxicity; vinegar or soured whey are the other agents listed here.

• Mascarpin de la calza, Lombardy traditional product description attributed to Regione Lombardia (copy hosted by ONAF)
• ONAF, Mascarpin de la calza cheese sheet
• ONAF (national organisation of cheese tasters), technical sheet 'Mascherpa d'alpe' (rock alum banned for its toxicity)

Also called masse.

Masse is the Mozambican member of a south-east African family of partly drained sour milks. Raw milk sours in a calabash, gourd or clay pot, some whey is taken off and fresh milk added until the pot is full of curd. FAO notes that in Mozambique the milk is curdled with a plant enzyme; the plant is not named.

1. Let raw milk sour and curdle in a covered pot3–4 days
2. Drain some whey, add fresh milk, repeat7 days

Safety: Made from raw, unheated milk. CDC says raw milk and products made from it can carry Campylobacter, E. coli, Listeria, Brucella and Salmonella, with higher risk of serious illness for pregnant women, adults over 65, children under 5 and people with weak immune systems.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II "Acidified milks", group 1.4 (partly drained or concentrated sour milks) and its remarks
• CDC, Raw Milk, Food Safety (page of 31 January 2025; raw milk and products made from it can carry Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella)

Also called мечниковская простокваша.

Mechnikov prostokvasha is a set sour milk made with thermophilic lactic streptococci and the Bulgarian lactic bacillus. Interstate standard GOST 31661-2012 defines it and sets its acidity at 80–110 °T, with an unbroken curd and no gas.

1. Pasteurise and cool the milk
2. Add the starter and set in the pack
3. Cool and release2–6 °C

Safety: The standard requires heat treatment of the milk and release from the plant at 4 ± 2 °C.

• GOST 31661-2012, Mechnikovskaya prostokvasha. Technical conditions (interstate standard, in force in Russia from 1 July 2013)
• ru.wikipedia, Простокваша (variant list only)

Also called নবদ্বীপের লাল দই, ক্ষীর দই, চাক্কু দই, Nabadwip-er lal doi, kheer doi, chakku doi.

Milk is boiled down on a wood fire until about three litres become one and the milk reddens, with no colour added. It is poured into clay pots set around the fuel, covered, and left to set into a curd firm enough that a pot can be turned upside down. A knife (chakku) is used to test or cut it.

1. Boil the milk down until it turns red2–6 h
2. Set in clay pots around the fire
3. Keep until eaten

Safety: The milk is boiled down for two to six hours on a wood fire before it is poured into the pots to set. Wikipedia says the curd can be stored up to ten days.

• Wikipedia, Nabadwip-er lal doi (citing Anandabazar 2012-2017, The Telegraph 2017, Ruj 2019)

Also called natilla, crema, crema ácida, natilla doble.

Natilla is cream soured by suitable microbes until its pH drops, with or without thickening; the regional regulation RTCA 67.04.71:14 also uses the name for cream soured with added acids. It must hold at least 10 % milk fat, or 45 % for natilla doble.

Milk fat, natilla

At least 10 % milk fat

Milk fat, natilla doble

At least 45 % milk fat

1. Separate and standardise the cream
2. Add the culture and ferment the cream
3. Pack

• RTCA 67.04.71:14, Productos lácteos. Cremas (natas) y cremas (natas) preparadas. Especificaciones, Central American Technical Regulation, annex to COMIECO resolution 363-2015

Also called простокваша, zsiadłe mleko, aludttej, Dickmilch, Sauermilch, tykmælk.

Raw milk is left covered at room temperature, often with a little of the last batch stirred in, until its own lactic bacteria sour it into a soft gel. Industrial prostokvasha is made the same way from heat-treated milk with lactococci or thermophilic streptococci.

1. Leave the milk covered to sour
2. Chill and keep cold2–6 °C

Safety: Household prostokvasha uses raw milk. The US FDA says raw milk has caused outbreaks of illness involving Listeria, Campylobacter, Salmonella and E. coli, and that the elderly, people with weak immunity, children and pregnant women are especially vulnerable. The industrial standard (GOST 31456-2013) allows no phosphatase or peroxidase and requires an acidity of 85–130 °T and storage at 4 ± 2 °C.

• Kochetkova T.V., Grabarnik I.P., Klyukina A.A. et al. 2022, Microbial communities of artisanal fermented milk products from Russia, Microorganisms 10(11):2140
• GOST 31456-2013, Interstate standard, Prostokvasha (sour clotted milk), Specifications, Standartinform, Moscow (in force from 2014)
• Wikipedia (ru), Простокваша (outline only)
• US Food and Drug Administration, Food Safety and Raw Milk

Also called non maí, yami.

Non maí or yami is the buttermilk left after churning raw cow's milk into butter in Niger. It is poured into a clean calabash with a little sour milk and left for 24 hours to sour, then keeps for up to 48 hours.

1. Churn raw milk and take off the butter
2. Sour the buttermilk with some sour milk24 h
3. Drink within two days

Safety: Made from raw, unheated milk and kept no more than 48 hours. The CDC says products made from raw milk can expose people to germs such as Campylobacter, E. coli, Listeria, Brucella and Salmonella, with a higher risk of serious illness for children under 5, adults over 65, pregnant women and people with weakened immune systems.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II "Acidified milks", group 1.3 (Arrera, Garoor, Non maí Yami)
• US Centers for Disease Control and Prevention, Raw milk

Also called piimä, kirnupiimä, surmjölk (Finland Swedish).

Piimä is a Finnish soured-milk drink, sour in taste and thicker than milk. Kirnupiimä is the buttermilk left when soured cream is churned into butter. In dairies the milk is pasteurised and then soured in a tank at about 18–24 °C for 15–24 hours.

1. Ferment milk or buttermilk15–24 h · 18–24 °C

Safety: Low risk.

• Wikipedia, Filmjölk (piimä is the thinner Finnish product)
• Wikipedia (fi), Piimä

Also called mala ya kienyeji, kamabele kambou, kamabele, kamabou, ash yoghurt.

Pokot ash yogurt is raw cow or goat milk soured for at least three days in a gourd smoked over cromwo wood (Ozoroa insignis), then drained of whey, shaken, and mixed with the ash of the same tree, which turns it grey and gives it an aromatic taste. Cow and goat milk are never mixed.

1. Hollow, dry and smoke the gourd
2. Let the milk stand in the gourdat least 3 days
3. Drain the whey and shake
4. Mix in the ash

Safety: Made from raw milk with no heat step. FAO notes that most Kenyan milk is boiled before it is soured, but the Slow Food account says this yogurt uses raw milk. CDC says foods made from raw milk can carry Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella, and that children under 5, adults over 65, pregnant women and people with weak immune systems face a higher risk of serious illness.

• Slow Food Foundation, Pokot Ash Yogurt Presidium
• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II 1.1 (lists kamabele/kamabou among Kenyan sour milks)
• Mureithi W. et al. 2000, Management of trees used in mursik (fermented milk) production in Trans-Nzoia District, Kenya, Journal of Ethnobiology 20(1):75–91 (notes that the Pokot coat milk gourds with charcoal)
• US Centers for Disease Control and Prevention, Raw Milk (31 January 2025)

Also called qatiq, катык, katyk.

Qatiq is a thick Turkic soured milk, firmer than ayran, made by keeping boiled milk warm for 6–10 hours. Kazakhstan's old standard ST RK 230-87 defined katyk as milk pasteurised at a high temperature with a long hold (baked) and soured with the Bulgarian bacillus, thermophilic streptococci and kefir starter.

Fat levels (Kazakh standard)

Full-fat katyk at 1.0, 2.5 or 3.2 % fat, and fat-free katyk

1. Boil the milk
2. Keep the boiled milk warm6–10 h
3. Keep cool

Safety: Made from boiled or pasteurised milk.

• Wikipedia, Qatiq (citing Food on the Move, Oxford Symposium 1997)
• ST RK 230-87, Katyk. Technical conditions, Kazakhstan standard (lapsed 1 July 2013; scope, types and raw materials read on the public extract)

Also called salcë shakulli, salcë në shakull, salce shakulli, hide-sack sauce, yogurt cream in a sack.

Salcë shakulli is sheep or goat yogurt salted and hung for months in a salt-cured goat or sheep hide. Whey seeps out through the skin and is scraped off while salted milk is added, so the yogurt thickens into a dense, salty cream that is ready by about November. Shepherds of the Përmet mountains make it to keep summer yogurt for winter.

1. Make the shakull (hide sack)6 months
2. Fill with yogurt and salt; rest5–6 days
3. Top up with salted milk; salt the outside daily5 days
4. Add milk once more, seal and mature2–3 months

Safety: Wikipedia's infobox lists it as not pasteurised; the other sources do not say whether the milk is heated. Products made from raw milk can expose people to germs such as Campylobacter, E. coli, Listeria, Brucella and Salmonella (CDC).

• Slow Food Foundation, Ark of Taste: Salcë shakulli (yogurt cream in a sack)
• Laurìa A., Flora V., Guza K. 2020, Five Albanian villages, guidelines for a sustainable tourism development through the enhancement of the cultural heritage, Firenze University Press, doi:10.36253/978-88-5518-175-4, pp. 49 and the action plan (food heritage of Përmet)
• AgroWeb 2022, Salcë në shakull nga stanet e Trebeshinës, 11 February 2022
• Regjistri i Trashëgimisë Kulturore Jomateriale (Albanian intangible cultural heritage register), Shëllira e Kaçupit (Kaçupi's brine)
• Wikipedia, Salcë shakulli
• US Centers for Disease Control and Prevention, Raw Milk (31 January 2025)

Also called снежок, snezhok.

Snezhok is a soured milk drink, usually with sugar or fruit-berry syrup added. It is made from pasteurised milk soured with Bulgarian bacillus and lactic streptococci. The body is sour-cream-like and slightly viscous.

1. Pasteurise the milk
2. Ferment, then sweeten

Safety: Low risk.

• ru.wikipedia, Снежок (напиток)

Also called somar.

Somar is a fermented buttermilk product of the Himalayas, made from yak or cow's milk. A study of Himalayan ethnic milk products isolated Lactobacillus paracasei and Lactococcus lactis from it; no published source found gives its making process in detail.

1. Churn the milk and keep the buttermilk
2. Ferment the buttermilk

• Dewan S., Tamang J.P. 2007, Dominant lactic acid bacteria and their technological properties isolated from the Himalayan ethnic fermented milk products, Antonie van Leeuwenhoek 92:343–352 (abstract)
• Tamang J.P., Watanabe K., Holzapfel W.H. 2016, Review, Diversity of microorganisms in global fermented foods and beverages, Frontiers in Microbiology 7:377, Table 1 (somar row)

Also called sữa chua, Vietnamese yoghurt.

Sữa chua is Vietnamese yoghurt, often made at home from sweetened condensed milk diluted with water and seeded with a little plain yoghurt, then set warm in small jars. As a yoghurt it falls under the Vietnamese fermented-milk standard TCVN 7030:2009, which follows Codex CXS 243 and requires the two yoghurt bacteria.

1. Dilute the condensed milk and warm it
2. Whisk in yoghurt and set in small jars

Safety: Codex CXS 243 requires yoghurt to reach at least 0.6 % lactic acid and to hold live starter bacteria at 10^7 cfu/g or more until the end of shelf life. This defines the product and does not test a home batch.

• Codex Alimentarius, Standard for Fermented Milks CXS 243-2003 (adopted in Vietnam as TCVN 7030:2009)
• Hệ thống pháp luật, summary of TCVN 7030:2009 (Codex Stan 243-2003) on fermented milks

Also called суорат, suorat, Yakut thick yoghurt, sorat.

Skimmed cow's milk is boiled, cooled to 35–36 °C and whipped with sour cream into a thick foam, then covered, wrapped in a blanket and left for a few hours to sour. The result is a thick, airy, buttermilk-tasting yoghurt, the commonest summer dish in Yakutia, once kept in birch-bark vats and frozen into slabs for winter.

1. Boil the skimmed milk
2. Cool and whip in sour cream35–36 °C
3. Cover, wrap in a blanket and sour5–6 h
4. Move to a cool place and stir before serving

Safety: The milk is boiled before the starter goes in. No safety study of suorat was found.

• ru.wikipedia, Суорат (citing make-eat.ru and yakutskhistory.net)
• Danilov I.A. 2019, Yakut dairy lexicon (Lomonosov-2019 conference abstract, Moscow State University)

Also called sýra, sýrublanda, blanda, blaand (Shetland), soured whey, fermented whey.

Sýra is the whey left from making skyr, kept in casks until it has soured for a long time. Diluted with water it becomes blanda, the everyday farm drink, and undiluted it was the acid in which Icelanders kept meat (súrmatur).

1. Collect the whey from skyr making
2. Sour the whey in casksat least 12 months
3. Dilute with water into blanda

Safety: Von Troil wrote in the 18th century that some meat was kept in casks under sour fermented whey, and that sýra was not thought fit for use until it was a year old. That is a historical account, not a safety test.

• Von Troil U., Letters on Iceland, in Pinkerton J. (ed.), A General Collection of the Best and Most Interesting Voyages and Travels, vol. 1, p. 656 (Project Runeberg scan)
• Wikipedia, Blaand (outline)
• Wikipedia, Skyr (outline)
• Wikipedia, Þorramatur (súrmatur; outline)

Also called тараг, ᠲᠠᠷᠠᠭ, tarak, chegen (Altai), chigee (China), Mongolian yogurt.

Tarag is the everyday soured milk of Mongolia, made from heat-treated cow, goat or yak milk, fermented naturally in a traditional container. Lactobacillus delbrueckii was the predominant species in 26 Mongolian samples, where mare's-milk airag was dominated by L. helveticus.

1. Heat the milk
2. Leave the milk to sour23–25 °C

• Oki K., Dugersuren J., Demberel S., Watanabe K. 2014, Pyrosequencing analysis of the microbial diversity of airag, khoormog and tarag, traditional fermented dairy products of Mongolia, Bioscience of Microbiota, Food and Health 33(2):53–64 (abstract)
• Kochetkova T.V. et al. 2022, Microbial communities of artisanal fermented milk products from Russia, Microorganisms 10(11):2140 (read via Europe PMC full text, PMC9697859)
• Wikipedia, List of fermented milk products

Also called tätmjölk, tettemelk, butterwort milk.

Tätmjölk (Norwegian tettemelk) is the old ropy sour milk that folklore says was started by adding leaves of common butterwort (Pinguicula vulgaris) to milk, then kept going by backslopping. A leaf study found lactococci, and genes for exopolysaccharide, on the plant, which fits the folklore. The leaf practice is no longer used.

1. Put butterwort leaves into the milk vessel
2. Leave the milk to sour and thicken
3. Start the next batch from the last

Safety: A folk practice no longer used; a butterwort leaf is not a controlled starter.

• Porcellato D., Tranvåg M., Narvhus J. 2016, Presence of Lactococcus and lactococcal exopolysaccharide operons on the leaves of Pinguicula vulgaris supports the traditional source of bacteria present in Scandinavian ropy fermented milk, Journal of Dairy Science 99:7049–7052 (abstract)
• Rampanti G. et al. 2024, Technological and enzymatic characterization of autochthonous lactic acid bacteria isolated from viili natural starters, Foods 13:1115
• Darwin Correspondence Project, letter DCP-LETT-9515 (C. Darwin, June 1874, on Pinguicula and milk; notes cite Linnaeus 1737, p. 10)

Also called karnemelk, laezh-ribod / lait ribot, kärnmjölk, kjernemelk, kærnemælk, bláthach.

Traditional buttermilk is the sour liquid left when naturally soured cream or milk is churned into butter. Lactic bacteria that soured the cream pass into the buttermilk, which is drunk thin and sour in parts of Europe.

1. Let cream or milk ripen
2. Churn

Safety: Cream left to sour on its own may be raw. The FDA says illness from raw milk and raw milk products has been linked to bacteria such as Listeria, and that pasteurization kills dangerous bacteria.

• US Food and Drug Administration, Food safety and raw milk
• Germany, Verordnung über Qualitätsanforderungen an Milchprodukte (Milchproduktqualitätsverordnung, MilchPQV) of 24.11.2025, BGBl. 2025 I Nr. 280, in force from 14.06.2026, Anlage 8 group IV Buttermilcherzeugnis (consolidated text on buzer.de)
• Österreichisches Lebensmittelbuch, IV. Auflage, Codexkapitel B 32 Milch und Milchprodukte (version of 18.1.2018), section 6.2.15 Echte Buttermilch (web.archive.org copy)
• Wikipedia, Buttermilk
• Wikipedia, Strained yogurt (hangop)

Also called турах, турӑх, turakh.

Turakh is the national soured milk of the Chuvash. Whole milk is held near boiling for hours until it browns, cooled, and soured with lactic streptococci and Lactobacillus acidophilus; at home it is baked in a Russian stove and soured with old turakh.

1. Heat the milk until it browns3–4 h · 95–98 °C
2. Cool and add the starter27–30 °C
3. Ferment12–14 h

Safety: The milk is held at 95–98 °C for hours before souring.

• ru.wikipedia, Турах (the process numbers are tagged "no reliable source" on the page)

Also called akile nukadwarak (FAO 1990), akile nukadwarak.

FAO lists akile nukadwarak among the Kenyan sour milks made by leaving the day's spare milk in a covered container for usually 24 to 48 hours, with no starter. The Turkana are reported to smoke their milk gourds; linking this FAO name to the Turkana is an inference.

1. Smoke the milk gourd
2. Leave the milk to sour24 h – 2 days · 22 °C
3. Drink

Safety: The souring is uncontrolled, so quality varies. FAO notes Kenyan milk is usually boiled before souring. If the milk is not boiled, it is raw milk. The US FDA links raw milk to illness from Listeria, Campylobacter, Salmonella and E. coli, and says the elderly, immune-compromised people, children and pregnant women are especially vulnerable.

• FAO 1990, The technology of traditional milk products in developing countries, Animal Production and Health Paper 85, section II 1.1 (akile nukadwarak, Kenya)
• Mureithi W. et al. 2000, Management of trees used in mursik (fermented milk) production in Trans-Nzoia District, Kenya, Journal of Ethnobiology 20(1):75–91 (cites Galvin 1985 on Turkana gourd smoking)
• US Food and Drug Administration, Food Safety and Raw Milk

Also called tykmælk, Danish thick milk.

Tykmælk is Danish thick sour milk. One home recipe sets whole milk with a little buttermilk, covered somewhere warm, in 24 hours; dairies now sour pasteurised milk with a lactic culture, and one adds an acidophilus culture too.

1. Heat or high-pasteurise the milk (dairy)
2. Add buttermilk or culture
3. Leave to sour and set24 h · 15–30 °C
4. Chill2–5 °C

Safety: Dairy tykmælk is made from pasteurised milk and kept at 2–5 °C.

• Kastrup C.B. (Mejeriforeningen, Danish Dairy Board) 2019, Spørg Fagfolket, Hvordan er kærnemælk fremstillet, Ingeniøren, 24 October 2019
• Arla Pro, Arla ØKO økologisk tykmælk 3,5 %, product sheet (producer page)
• Nielsen K., Danish tykmælk recipe, Nordic Food Living
• da.wikipedia, Tykmælk (outline)

Also called žinčica, žentyca, zincica, zentyca.

Žinčica is a lightly sour drink made at shepherds' huts from the ewe's-milk whey left after making lump cheese (hrudka), the raw material of bryndza. The whey is heated until its proteins float up as a thick layer (urda), which is skimmed off, stirred, cooled and left covered overnight to sour.

1. Collect the whey from the cheese make
2. Heat the whey until the proteins rise90–95 °C
3. Skim off the urda
4. Stir, pour and cool50 °C
5. Cover and sour until the next day

Safety: FermDB has the whey heated to 90–95 °C before it sours, then soured to pH 5.2 or below and drunk cooled. Lauková et al. 2020 tested 7 enterococcus isolates from žinčica from farms in central Slovakia. All were hemolysis-negative and none had the cytolysin A gene, but five carried another virulence gene (gelE, agg or esp) and four formed biofilm. The abstract covers enterococci only, not other pathogens.

• Stoličná R. 2017, Žinčica, Tradičná ľudová kultúra Slovenska slovom a obrazom (electronic encyclopedia, Centre for Traditional Folk Culture), citing Podolák J., Tradičné ovčiarstvo na Slovensku, 1982
• Lauková A., Kandričáková A., Bino E. et al. 2020, Some safety aspects of enterococci isolated from Slovak lactic acid dairy product žinčica, Folia Microbiol. 65(1):79–85, doi:10.1007/s12223-019-00703-5 (abstract)
• FermDB (Bokulich lab, ETH Zurich), FermDB_data.tsv, row Zincica (description drawn from Lauková et al. 2020), CC BY 4.0
• sk.wikipedia, Žinčica (outline; Šariš and Spiš variant)