Sour beers have a long and rich history. In fact, when beer brewing began hundreds of years ago many beers were sour, as they contained naturally occurring bacteria which gave the beverage its distinctive sour taste. Each variety is intrinsically linked to the places where these beers were born, from the Belgian Lambic and Flanders Red Ale, to the German Gose and Berliner Weisse amongst other signature European styles traditionally brewed through the spontaneous fermentation.
In the last few years, sour beers have been reborn and rediscovered by both brewers and drinkers alike. This resurgence is linked to brewers' constant search for new twists on the most popular beer styles – those that maintain the natural acidic flavours of sour styles but with a less sharp taste. This is possible thanks to a fermentation process guided by carefully selected microorganisms (lactic bacteria and yeasts), which ultimately lead to a lower acidity level with reduced phenolic and acetic notes.
The lactic fermentation of sour beers requires a specific set of solutions. FERMO Brew Acid is a yeast that is used instead of lactic acid bacteria in the wort acidification process. It belongs to the Lachancea thermotolerans species, isolated from spontaneous fermentation by the University of Dijon. Its uniqueness lies in its ability to transform monosaccharides in the wort into alcohol and lactic acid. The result is an extremely pleasant and well-balanced beer with a rounded, refreshing acidity.
The wort can be enriched with nutrients provided by Fermoplus Fruity or Fermoplus Fragrance if desired. Once the pH level is higher than 0.3 from the desired pH, the second strain can be pitched to stop the acidification activity and complete the further alcoholic fermentation.
Other benefits by using FERMO Brew Acid is the reduction of the brewing costs since there is no need for expensive acidified malt in the mash, neither any addition of lactic acid to the wort kettle nor the use of mixed microflora (i.e. beer spoilage bacteria and yeasts) during the beer fermentation.
FERMO Brew Acid offers brewers plenty of opportunity for customisation: from inoculation with conventional brewing yeasts (S. cerevisiae) to maturation in wooden barrels and the use of fruits or other flavouring ingredients. Its combination with various brewing yeasts allows you to brew any sour beer variants, even heavily hop forward worts or dry-hopped beers such as American-style Sour Ales.
Last but not least, FERMO Brew Acid can develop varied fermentative aromas and fruitiness in taste and a complex aftertaste, which can be controlled and adapted through the fermentation temperature.