Main fermentation

Once the cooled wort has been filled into a fermentation vessel (12 L/30 L/60 L PE vessel with drainage tap – see accessories), add the yeast to the wort. We recommend using dry yeast as it is easy to add to the vessel. This is the phase in which you need to decide whether you would like to prepare bottom-fermented or top-fermented beer. Top-fermented yeast requires 15 to 23°C for the fermentation process, whereby bottom fermented yeast becomes active at 4 - 12°C. The amount of yeast depends on the respective recipe and the desired type of beer. Wheat beer and Kölsch are top-fermented beers. Märzen and Pils, however, are bottom-fermented beers. Alcoholic fermentation of the beer is started by the activity of beer yeast organisms, which causes the fermentable sugar to be converted into alcohol and carbon dioxide. After adding the yeast, immediately seal the container with a lid and fermentation lock. Sulphuric acid should be filled into the fermentation lock so as to ensure that no foreign organisms enter the vessel. It is imperative that you perform this work step in absolutely sterile conditions as well to prevent the beer from becoming infected by foreign organisms. The vessel may never be completely sealed to allow the CO2 resulting from the fermentation to escape. Place the vessel in a darkened room that has the correct temperature for the yeast. A fridge that is not set too low can be used for fermentation of bottom-fermented beer. Top-fermented beers can be fermented at room temperature. For this reason, beginners are recommended to start with top-fermented beer types, as not everyone has an additional fridge at their disposal. Maintaining the temperature is extremely important. Temperatures that are too low cause the yeast cells to become active too slowly or not at all. Temperatures that are too high can lead to the yeast cells dying off. Fermentation should be active 6-12 hours after the yeast has been added; you can determine this by simply checking for escaping gas bubbles from the fermentation lock. Fermentation takes 2-4 days. Dark yeast spots may occur on the fermentation foam during the fermentation process. These can be removed by means of a sterile wooden spoon. Should you remove wort via the drainage tap during the main fermentation period (e.g. for measurements using the beer spindle), immediately clean the tap and disinfect using a cotton-wool ball and sulphuric acid where necessary. This prevents surface drying and subsequent infection by inherent bacteria during decanting.