Wild & Spontaneous
sour beers

( sour beer )

In 2019, at the Mlinarica brewery, we launched a series of beers quite unusual for our area: Mixed fermentation sour beers. What exactly are they? These are beers in which different strains of yeast and bacteria
are added during the fermentation or aging of the beer. The bacteria responsible for sour beer are Lactobacillus and Pediococcus, while the yeast main responsible for the „wild“ and „funky“ aromas is called Brettanomyces.

It is considered that before the Industrial Revolution, the development of the microscope, and the isolation of bacteria – for the latter we owe credit to Louis Pasteur – every beer was a sour beer and most likely had „semi-wild yeasts“ in it. If we go even further into the past, when beers were aged in wooden barrels, then it is certain that most beers were
and that they had Brett present in them.

At that time, it was normal to serve such beers to people. Of all the countries, only Belgium has maintained the tradition of producing them to this day, while some breweries are again reviving the production of sour beers, such as Jester King, The Bruery, and many others, including ourselves.

In Mlinarica, such beers are fermented using selected yeast. After the main fermentation, the beer is left to age in barrique barrels (in which wine was aged previously) and then enriched
with a blend of yeast, bacteria, and various seasonal fruit. During aging, we are getting a sour beer of deep complexity that comes from wooden barrels – and this depends on the age and the wood of the barrel – and from Brettanomyces and other bacteria.

You can find more information about this kind ove beers in our blog post about sour beer.