Not many foreigners have ever heard about kissel - a traditional Russian beverage. Actually it’s too substantial to be a drink - you can become full after one cup. That’s why many people consider it more as a dessert, especially because it is usually quite dense, almost like a jelly.
It used to be an everyday dish made from seasonal products (berries or oats) and could be cooked all year around. It’s commonly believed that kissel is very good for the stomach and it’s also a nutritious meal for the Great Lent.
There is a Russian saying: “Milky rivers with kissel coasts”, which basically means “paradise”. I think you can guess what role kissel played in everyday Russian life for centuries.