Why the foam on Belgian beers lasts so long

Summertime is beer time-even if the consumption of alcoholic beer is declining in Switzerland. And for beer lovers, there is nothing better than a head of foam topping the golden, sparkling barley juice. But with many beers, the dream is quickly shattered, and the foam collapses before you can take your first sip. There are also types of beer, however, where the head lasts a long time.