What Is Kashk? A Guide to Persian Dried Whey
Kashk is a tangy, salty dairy product at the heart of many Persian and Afghan dishes — but it’s unfamiliar to most Western cooks, and its dried, chalky-white form doesn’t look like anything in a typical grocery store. Here’s what kashk actually is, the different forms it comes in, and how to use it.
What Is Kashk?
Kashk is made from strained yogurt whey or buttermilk that has been fermented, salted, cooked down and dried into a concentrated, intensely tangy dairy product. Its flavour is often compared to a cross between sour cream, feta and parmesan — salty, sour and savoury all at once. It is a staple across Persian, Afghan, Iraqi and Kurdish cooking, most famously as the finishing touch on kashk-o-bademjan and ash-e reshteh.
Food-science literature describes kashk as a fermented dairy product made from raw sheep milk or cheese-making by-products such as buttermilk, which are “fermented, salted, and dried,” and sold in both liquid (industrial) and dried (traditional) forms. The name itself records the method: kashk derives from the Persian khushk, meaning “dry.” It is an old food — references to it appear as far back as the 10th-century Shahnameh.
Why Kashk Was Invented: Preservation Without Refrigeration
Kashk is best understood as a preservation technology. Cheesemaking and butter-churning leave behind whey and buttermilk — nutritious, but highly perishable. Fermenting, salting and sun-drying that by-product converts it into something shelf-stable: researchers note that dried kashk “can be kept at room temperature for a long time without spoilage or reduction in nutrients.” In a pastoral economy without refrigeration, that turned a waste stream into a protein reserve that lasted through winter.
The traditional apparatus reflects those origins — the mashk (a dried sheep-skin churn), the tolom (a hollowed tree-trunk churn) and copper pots, with the finished curd shaped into balls and sun-dried.
What Is In Kashk
Published analysis describes kashk as containing “large amounts of proteins, B complex vitamins, minerals such as calcium, potassium, and organic acids (such as lactic acid).” Because the dried form has had nearly all its water removed, it is strikingly protein-dense: compositional studies of traditional Iranian dried kashk report protein on the order of ~51 g per 100 g, against roughly 8.7 g per 100 g for the liquid form. That is the single most useful thing to understand about buying kashk — dried and liquid are the same food at very different concentrations, which is why dried kashk must be rehydrated rather than used straight.
The Fermentation: What the Microbiology Shows
Kashk is a live-fermented food, and its bacteria have been studied directly. A 2022 study in Foods isolated eight lactic acid bacteria strains from kashk sampled in two Iranian regions (Abadeh and Kalat) — including Lactiplantibacillus plantarum, Lactococcus lactis, Pediococcus pentosaceus and several Enterococcus species — and screened them for probiotic characteristics. Two P. pentosaceus strains performed best on bile-salt resistance, adhesion and antimicrobial activity.
A note on what that does and does not mean: this research identifies promising bacteria isolated from kashk under laboratory conditions. It is not evidence that eating kashk delivers a probiotic health benefit, and commercially produced liquid kashk is typically heat-treated. Treat kashk as a flavourful traditional food with an interesting microbiology, not as a supplement.
Forms of Kashk
Dried Kashk
کشک خشک — The most common form outside of Iran — hard, dried pieces or strings of kashk that need to be soaked and blended with water before use. Comes in a few shapes: round, string, and moshti (ball-shaped) kashk.
Liquid Kashk
کشک مایع — Ready-to-use kashk in a jar or bottle, already blended to a pourable, yogurt-like consistency — no soaking needed. Shop Khoban Kashk or Goaldees Kashk.
Qaraqorut
قره قروت — The dark, intensely sour form, reduced much further than the pale kashk above; the name pairs Turkic qara (black) with qurut (dried curd). It is used two ways: broken up and dissolved in hot water into a sharp sour sauce, the standard method in Afghan cooking, and eaten hard straight from the bag as a sour snack. Both are traditional — it is the sourness, not the format, that defines it. Shop qaraqorut.
Afghan Kashk
قروت افغانی — A style of dried kashk specific to Afghan cuisine, used similarly to Persian kashk but with its own regional character. Shop Afghan kashk.
How to Use Kashk
- If using dried kashk: soak the pieces in warm water for 20-30 minutes until softened, then blend with a bit of water until smooth and pourable.
- If using liquid kashk: it’s ready to use straight from the jar — just stir before using.
- As a topping: drizzled over kashk-o-bademjan (fried eggplant), kashk-e-bademjan dip, or ash-e-reshteh (noodle soup), often with a swirl of fried mint and onion on top.
- As an ingredient: stirred into some stews and dips for a tangy, savory depth.
Try It in a Dish
New to kashk? The easiest way to try it is in a ready-made dish: try our kashk-o-bademjan recipe (eggplant with kashk). Or make a batch of ash reshteh noodles and top the finished soup with kashk for the traditional presentation.
Frequently Asked Questions
What does kashk taste like?
Kashk is tangy, salty, and savory — often compared to a cross between sour cream, feta cheese, and parmesan, with a distinctive sourness from the fermented whey it’s made from.
Is kashk the same as yogurt?
No. Kashk is made from the by-products of yogurt and butter making — whey or buttermilk — which are fermented, salted and dried into a far more concentrated product. Dried kashk contains roughly 51 g of protein per 100 g in published analyses, against about 8.7 g for liquid kashk, and both are far more intense in flavour than plain yogurt.
Where does the word kashk come from?
From the Persian khushk, meaning “dry” — a direct reference to the sun-drying step that makes the product shelf-stable. Kashk appears in Persian sources as early as the 10th-century Shahnameh.
Is kashk a probiotic food?
Kashk is a fermented dairy product, and researchers have isolated lactic acid bacteria from it — including Lactiplantibacillus plantarum and Pediococcus pentosaceus strains that showed promising probiotic characteristics in laboratory testing. That is not the same as evidence that eating kashk provides a probiotic benefit, and commercial liquid kashk is usually heat-treated. Enjoy it as a traditional food rather than a health supplement.
How do I use dried kashk?
Soak dried kashk in warm water for 20-30 minutes until softened, then blend with a little water until smooth and pourable, ready to use as a topping or ingredient.
What dishes use kashk?
Kashk is most famously used in kashk-o-bademjan (eggplant with kashk) and ash-e-reshteh (herb and noodle soup), typically drizzled on top as a finishing touch.
Sources
- Investigating the Probiotic Properties and Antimicrobial Activity of Lactic Acid Bacteria Isolated from an Iranian Fermented Dairy Product, Kashk — Foods, 2022;11(23):3904. Description of kashk, its production, and isolation of eight LAB strains.
- Geographical differentiation of traditional Iranian dried kashk based on gross composition, fatty acids, elements, free amino acids and vitamins — Journal of Food Composition and Analysis. Compositional analysis underlying the dried vs. liquid protein figures.
- Microbial Diversity and Nutritional Properties of Persian “Yellow Curd” (Kashk zard) — background on kashk-family fermented foods and their production steps.
This article covers the food science and culinary use of kashk. It is general information, not medical or dietary advice; kashk is a dairy product and contains salt.
Shop the Full Kashk Collection
Browse the complete range of authentic dried and liquid kashk at Goaldees (also searched as Goldis), shipped fresh, nationwide across the US. Shop the full kashk collection.
