In the Czech lands, as also in neighbouring Austria and Slovakia, the consumer, at the time of the wine harvest, loves nothing more than to consume the still-fermenting grape juice. The partially fermented grape juice is a product gained by the fermentation of the grape must to a real alcohol content of more than 1% alc. by vol. and less than three-fifths of the total alcohol content in a percentage by volume.
The partly fermented grape juice must only be offered for sale under the banner "burčák" between 1st August and 30th November, provided that the juice has fermented and the grapes came solely from vineyards in the Czech Republic.
Burčák contains large amounts of yeasts and vitamins, especially vitamins of the B group. One of these is thiamin, otherwise known as vitamin B1, which supports cardiac activity. Another highly positive effect is its cleansing effect on the digestive system.