Its name is derived from a Slavic word meaning "sour" (cf. Russian кислый kisly), as sour fruits are preferred.
Kisel (kee-‘sel) is a thick, starchy drink made mostly of fruit and berries. Kisel can be also made of oats or wheat or peas, which I wouldn’t dare to try. I do admit that this can be really healing for a diseased stomach though. What’s interesting is that oatmeal kisel is one of the oldest Russian dishes ever. There’s a legend telling about an ancient Russian city besieged by nomadic tribes and suffering from famine until an old sage told the citizens to collect all remaining oats and all honey they could still find in their cellars. The citizens did as the wise man told them and brewed kisel from the oats, and sweet drink from the honey. They made two new water wells and filled them with kisel and honey drink, then invited a delegation of nomads, showed them the wells full of drink and kisel, and assured the guests that they had enough food to survive. The nomads were astonished at the fact that Russians obtained food directly from their land and told their king about the miracle. The situation seemed pretty hopeless. The siege was raised, and the nomads went away in search of a different city to conquer.
There’s also the expression “Milk rivers and kisel shores” in the Russian language, which is used to describe carefree and prosperous life.
You see how important this drink is in Russian culture?
You can have kisel as a soothing drink or serve it with cream of rice, rice pudding, oatmeal cream, or with all kinds of mousse, cream, and custard.