Largely referred to as "Russian cola," kvas has been the country's summer drink of choice for many years.

After vodka, the drink closest to Russian hearts, kvas is made from fermented black or rye bread and comes in somewhere between a soft drink and a beer. The nominal alcohol content, however, means that it can be given to children and thanks to the yeast in it, kvas is a rich source of vitamin B.

In the Middle Ages, the making of the drink was even considered as essential knowledge for any woman wanting to be a good wife.

Now kvas is the basis of a multi-billion dollar industry: the largest kvas brewery in Moscow produces 2 million liters of the drink per day.

In June 2010, soft drink giant Coca Cola launched sales of kvas in the US, under the brand name Krushka & Bochka.

Although nowadays few enthusiastic wives are eager to make kvas at home, they still most probably know how to use kvas to cook the traditional Russian cold soup called okroshka.

The name "okroshka" comes from the Russian word meaning "chopped," as the cooking process includes much chopping: radishes, spring onion, dill, potatoes, cucumbers and eggs are cut into small cubes, stuffed with sour cream and doused with kvas.