Unsour beer is, relatively, a new invention of brewers in the last couple of hundred years. Being unenlightened as to the nature of beer with respect to microbiology, our ancestors were unable to divine what exactly made beer, except to say that it was a magical process that had to do with this brown sediment that tended to accumulate at the bottom of fermentation tanks. For centuries our relatives drank sour beer gladly and copiously; a rather dramatic change from the modern day perspective of sourness as a ‘defect’ in beer. Nonetheless, there are modern breweries today who have stood adamantly and steadfastly against the marching tide of progress in microbiology control, cleaning and sanitation. These breweries held onto brewing methods and traditions millennia old. I am talking of course about the lambic and sour beers of Belgium, France and the lower countries. These breweries have changed their brewing methods very little over their long existence, and the process can radically differ from ‘traditional’ or ‘modern’ methods.
Mashing and lautering are very much similar to widely used processes, however the boil can be much longer (up to 5 hours!) than a traditional boil and, instead of being cooled immediately, is run off to wide open shallow vessels called coolships and allowed to be cooled by the drafts of air flowing through the open windows of the brewery. They also use hops that have been aged for year(s) or more to deplete the aroma and flavor leaving behind the preservative qualities, and are used sparingly as well. The wort is left to cool overnight and is then sent to the fermentation tanks (or wooden barrels/vats in some cases). They add no yeast whatsoever (some of the more modern ones will pitch sediment from the previous batch). For the most part, the wort is ‘infected’ with yeast from the natural microflora living in the brewery and the air surrounding the outside. Not surprisingly, many of these breweries are located close to orchards where the fruit they add to their beer for flavor comes from. This might very well explain the abundance of microflora suitable for wine and beer fermentation being naturally and widely endemic to these areas. After the beer has fermented for a few months, it will have a very funky and sour aroma to it, but this will often smooth out as the beer ages. Being a sour beer, and fermented with a whole microbial community as opposed a single strain, these beers lend themselves unusually well to long term aging. Fruit is typically added after between 1-2 months of fermentation and then is allowed to sit for an average of 8-months to a year before being tasted and blended for bottling. Even then, most breweries will set aside some of the batch for long term aging in their cellars and for blending into an incredibly rich and complex beverage called ‘gueze’. Gueze is just blended sour-lambic beers of different ages and possibly different fruit additions to yield a beverage unparalleled for complexity and flavor.
Here at MobCraft, we have already brewed both a lambic and a sour. For the sour, we culled sediments from a previously brewed batch and have been propping it up since, it contains Brettanomyces Bruxelensis and Lambicus, Pediococcus, Lactobacillus Delbruckeii, Lactis and Thermophilus. We have also brewed a lambic before with a sourdough starter as the souring agent with Hibiscus and Strawberries, called the Bloodletter Lambic.