Beer History: The 'Other' Sour Beers Even among the craft beer
cognoscenti, sour beers were something of a rarity just a few
years ago; the New York Times noted that less than a decade ago,
sour beers of all sorts could only muster up 15 entries at the
Great American Beer Festival. Last year there were 149, in four
separate categories—certainly an indication of growth. While
it's true that the majority of sour beers available today are of
Belgian origin, (and there is much variety among those) there is
plenty of historical precedent elsewhere for sour styles of
beer. How did those sour flavors come about in the first place?
Medieval European brewers relied on spontaneous
fermentation—that is, wild yeast (and other friendly bacteria)
would turn their wort into beer. Flavors would vary depending on
the local environment's yeast population, but over time, many of
these 'good' sour styles became standards. After the discovery
of yeast in the 19th century, most commercial brewers switched
to carefully-managed yeas