Šaltibarščiai (Cold Beetroot and Kefir Soup)

Variations

• This is not borscht that has been chilled. That page notes it is sometimes served cold in summer, and this is a different dish. Borscht is built on a beef broth with cabbage, potato and carrot simmered together; this has no broth, no meat, no cabbage, and nothing in it is cooked together at all. Two separate dishes out of one root vegetable.
• Polish chłodnik / Belarusian khaladnik: essentially the same soup under other names. The Polish version often uses the beet leaves and stalks as well.
• With raw beetroot: very young beets can be grated, salted briefly and used raw. Much brighter in colour and far more earthy.
• From pickled beets: Lithuanian households often use pickled beetroot or its brine straight. The acid is already there, so cut the vinegar.
• With chips instead: fried potatoes rather than boiled is how most Lithuanian restaurants serve it now.
• No kefir: plain yoghurt let down 4:1 with water, or buttermilk. Sour cream alone is too heavy.

Tips

• The problem dairy and heat is about never arises. That guide gives three causes for dairy splitting — "Boiling. Acid. Salt plus prolonged heat" — and says "add tomato or lemon to a milk-based sauce and it curdles." All three of those causes require heat — or, failing heat, the mechanical work of a whisk, which nothing here applies either. This soup pours a litre of kefir over sharply acidic beetroot and vinegar and nothing happens, because nothing in it ever meets heat. Being cold is not this dish's preference; it is its permission.
• Which makes it the exact inverse of dovga. That soup also uses a litre of soured dairy as its liquid, and it boils — so before any heat reaches it an egg and two tablespoons of flour have to be beaten in, putting protein and starch physically between the casein. One problem, two answers: stabilise it, or never heat it.
• The potatoes stay out of the bowl for the same reason. Hot potato would push the kefir up toward the splitting range, and its starch would cloud the soup. Serving something hot alongside is a temperature contrast and a safeguard at once.
• The vinegar is in the pot for the colour. Borscht says "add the vinegar/lemon while cooking the beets to lock in the vivid red" and does not say why. Betanin is a pH-sensitive pigment: at neutral or alkaline pH heat and time break it down to brown, and in acid it holds up far longer. In a hot soup that is cosmetic; in a cold one the colour is the dish — a brown šaltibarščiai reads as spoiled.
• Season it after it is properly cold. Low temperatures suppress saltiness and sweetness, so anything seasoned lukewarm will taste flat — gazpacho rests on the same rule.
• Do not be sparing with the dill. Nothing in this soup is fried or cooked, so every aroma in it comes from raw herbs (fresh herbs).