Flavoured fats & thickeners
Tarag
Таpaг · Tarag is a foundational live-culture fermented milk base used across the cuisines of the Mongolian, Buryat, Kalmyk and Tatar peoples. It is prepared by back-slopping boiled milk with a portion of a previously fermented batch (or natural yogurt) and holding it warm until it thickens and acidifies. Depending on region and culture strain it functions as a plain yogurt-style curd or, when a yeast symbiont is present, a mildly effervescent kefir-like base. It is the reusable lactic backbone for beverages, milk-tea broths, sauces, dumpling fillings and the mother culture from which airag (mare-milk ferment) is propagated.
The formula
1:10 live-culture starter : boiled milk (≈100–200 ml starter per 1 L milk)
Back-slopped from the previous batch. The Isgelen/Mongolian form additionally carries a Lactobacillus–yeet symbiont that produces CO₂ and trace alcohol.
Identity
- Foundational lactic-acid base, not a finished dish
- Reusable component: a portion of every batch is reserved as the inoculum for the next
- Made from boiled whole milk of cow, yak, goat, sheep or mare
- Fermented by thermophilic/mesophilic Lactobacillus, sometimes with a yeast symbiont (kefir-type)
- Widespread across Central Asian, Mongolian, Buryat, Kalmyk and Tatar cuisines
- Functions as acidulant, thickener, beverage and mother culture for airag
Ingredients
| Base | whole cow, yak, goat, sheep or mare milk | Boiled first; mare milk is rare and reserved mostly for airag propagation. |
| Culture | live yogurt or reserved previous-batch tarag (back-slop) | Added at hand-warm temperature (~40 °C). Acts as both ferment and live-cultured souring agent. |
| Enrichment | rye bread + sour cream slurry | Buryat household shortcut — crumb of dark rye bread blended with sour cream and a little warm milk is used as the wild starter in lieu of back-slop. |
| Liquid | cool boiled water | Optional dilution if the finished tarag is too sharp or thick for drinking. |
Method
- 1Strain and boil the fresh milk, then cool to hand-warm (~35–40 °C).Boiling sterilises the substrate and concentrates the whey proteins so the curd will set; cooling prevents killing the live culture in the next step.
- 2Stir in the reserved tarag, natural yogurt or bread-sour-cream starter at roughly 1 part starter to 10 parts milk.Back-slopping supplies the dominant Lactobacillus (and yeast, in the Mongolian isgelen form) needed to acidify and slightly carbonate the milk.
- 3Pour into a clean vessel (thermos, ceramic pot or wooden khokhuur) and hold warm for 12–24 hours.Mesophilic/thermophilic Lactobacilli need a stable, body-heat range to multiply and drop the pH enough to coagulate casein.
- 4Stir periodically with a wooden masher (buluur) once the milk begins to thicken.Agitation breaks the curd into a uniform, drinkable body and, when yeast is present, distributes CO₂ evenly through the liquid.
- 5When the tarag smells gently sour and holds a spoon, refrigerate and reserve ≈10 % as the mother culture for the next batch.Cooling arrests fermentation; reserving a portion keeps the strain alive and self-perpetuating in the household.
Techniques that matter
Back-slopping
Re-inoculating each batch with a portion of the previous one maintains a stable, house-specific culture indefinitely.
Boil-and-cool inoculation
Hot boiling then cooling to hand temperature gives a low-bacterial substrate ideal for the chosen culture to dominate.
Wooden-masher agitation (buluur)
Traditional Mongolian stirring breaks the curd and, with yeast symbionts, builds the characteristic gentle fizz of isgelen tarag.
Variations & derivatives
Isgelen taragMongolia
Kefir-like version carrying both Lactobacillus and yeast; mildly effervescent with trace alcohol, stirred with a buluur.
Buryat taragBuryatia
Often started with rye-bread-and-sour-cream slurry; thicker and richer from the added cream.
Kalmyk taragKalmykia
Made primarily from cow and occasionally camel or sheep milk; used as both drink and soup base.
Mongolian low-fat taragMongolia
Frequently prepared from the skim left over after churning urum (cream) — a traditional byproduct use.
Used in these dishes
Substitutions
- Mongolian yak milk → cow milk — Whole cow milk is the standard substitute in non-pastoral kitchens.
- Previous-batch tarag as starter → plain live yogurt (no additives) — Commercial plain yogurt with active cultures is the accepted modern back-slop.
- Live kefir grains → back-slopped tarag — Kefir grains can seed a similar product but will shift the flavour toward yeasty/tart.
- Rye-bread + sour-cream starter → whey + live yogurt — Used when neither bread nor cream is available; produces a thinner, more acidic tarag.changes result
Troubleshooting
Tarag stays thin and watery
Inoculation was too small, milk was not cooled to hand-warm, or the starter culture was no longer alive. → Increase starter to 15–20 % of the milk volume, verify milk is ~40 °C before adding culture, and use a fresh live-culture yogurt if back-slop is suspect.
Tarag is harshly sour or sharp
Fermented too long or held too warm, driving pH too low. → Shorten the warm hold to 8–12 hours and chill immediately once the curd sets; dilute finished tarag with a little cool boiled water.
Bitter or off-flavour
Contaminated vessels, or a yeast-heavy culture running wild at high temperature. → Switch to a clean glass or ceramic pot, refresh the back-slop with a new live yogurt, and keep fermentation below 40 °C.
No effervescence in isgelen tarag
Yeast symbiont absent from the starter (e.g. pure yogurt used instead of true kefir-type grains). → Source a portion of authentic isgelen tarag or live kefir grains to reintroduce the yeast partner.