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pan called a coolship. The air – or rather the bacteria and yeast carried on the air – serves to inoculate the wort. Additionally, the beers are exposed to oak barrels where bacteria and yeast that are native to the barrel’s environment can grow. The IBUs are generally kept low (approximately 10 IBU) to allow for the bacteria to grow. SELECTING A SOURING PROCEDURE There are two main ways of producing a sour beer using micro-organisms. Either the wort is soured prior to the boil or it is soured post boil, during the fermentation stage. You could also use a charge of pale malt that was subjected to lactic acid fermentation after kilning (acidulated malt) instead of relying solely on micro- organisms. However, the micro-organisms are almost always used. Kettle sours In kettle sours, the souring of the wort is performed in the kettle after a normal mash. The appropriate pre-selected culture is inoculated into the wort (completing the souring process in 12-24 hours), or spontaneous souring is left to occur (taking two to three days). Once the target pH and perceived acidity have been reached, the normal boiling process is initiated and followed by fermentation to produce the final beer. An advantage of this method is that the souring process is controlled and boiling at the end of souring serves as means of protection. It does however add extra time and cost to the final production of the beer. Souring during fermentation or ageing In fermentation sours, the wort is processed in a normal fashion on the hot side and made ready for fermentation. A yeast such as Lachancea is then inoculated into the wort to produce lactic acid as well as alcohol during the fermentation stages. The alcohol production itself usually occurs once a pH limit has been reached (approximately 3.4 pH after 24—48 hours) but it can occur sooner depending on the composition of the wort. An advantage of this method is the low risk of infection. It allows for an extra level of customisation since one can inoculate a second yeast that is to your preference and will complement the intended style after the souring stage. Alternatively, souring can be performed in a barrel. The microflora in the barrel will usually be undefined and allow for souring during extended ageing. SOUTH AFRICAN SOURS South Africa has been seeing an increase in sour beer production, particularly in the Western Cape. More recently, due to the launch of new yeast and bacteria strain, more sour beers havemade their way to the market. Patiala Brewery’s Gose was the first beer in South Africa to be produced with the Lachancea spp. Soon to follow was Afro Caribbean Brewing Company’s Optical Distortion as well as the Watermelon Sour from The Kennel Brewery. Other notable sour beers are the Plum Lambic and Flemish Acid Ale from Hazeldean Brewing Co, Stoned Vol 1 Fruit Sour from Devil's Peak and the Live Culture from Soul Barrel, all of which utilise wild fermentation and barrel ageing. Indeed, the South African interest in sour beers has been on the rise. It is still relatively unexplored when compared to other styles of beers such as pale ales and IPAs. Sour beers should appeal to anyone who is looking for a drink that is refreshing and different to a normal beer. And indeed some who do not usually drink beer may actually end up enjoying sour beer. The acidity lends itself to interesting food pairings much like those we see in the wine world. The methods outlined here provide the brewer with more than one avenue to achieve a sour and a challenge to become a master of at least one of them. |       ™    €  