After the new generation of beer lovers reacquired an appreciation of hops through the onslaught of IPAs originating in North America, and knowledge of the power of grain, through the emergence of stouts, wheat beers and others, the turn came for yeast to take the stage.
The obvious common theme between Saison, Lambic and Oak-Aged beers is that their recent origins are Belgian. The less well appreciated but more scientific link is that in different ways their fermentation and conditioning involves at some point bugs other than saccharomyces yeast.
Naturally occurring, so-called ‘wild’ yeast are found everywhere. They are even carried on the wind and land on surfaces. Traditionally made wines and ciders would be fermented by the wild yeast caught in the skin of the fruit. Working inside an oak cask, alongside bacteria such as lactobacilli and pediococci, the flavours that they can develop are variously sharp, tart, musty, tangy, rustic and indefinably ‘vintage’.
Up until the latter half of the 19th century, these sorts of flavours featured routinely in stronger beers. During the next hundred years, possibly driven by the arrival of cheap sugar from colonised lands in the tropics, public tastes changed to preferring sweet tastes over sharp, and only the very best survived.
The new-style “sour” and “wild” beers that have been trending in recent years, despite many tasting pretty horrible, derive their inspiration from these older styles, but by and large not their production methods.