The brewing process
Since 1858, beer has been brewed at the “Brauerei zur Malzmühle” in the very heart of Cologne’s old town. Then as now, this is done by hand and according to the German Purity Law of 1516. Here you can discover why our Mühlen Kölsch is a character beer that still tastes like craftsmanship.
Our own well water, which flows from the Eifel in brooks below the brewery into the Rhine, is the basic ingredient of our products. According to an old family recipe from 1858, only natural raw materials of the highest quality such as barley malt and a small proportion of wheat malt as well as high-quality aromatic hops and yeast are used.
The malt is ground in the brewhouse. The shell, the so-called husks, are retained during this squeezing and grinding process. The grist is mixed with 54°C warm water in a pre-mashing vessel and becomes the mash, which is heated again. In this process, the enzymes that have formed in the malt reach their ideal temperature and can then turn starch into fermentable sugar.
Following the mashing, the front wort is separated from the solid components, the spent grains, in the lauter tub. After sweetening the spent grains with water, we pass it on to our regional farmers as high-quality animal feed. The wort is now boiled under three doses of the Hallertau aroma hops to give the Kölsch its natural tart taste. Shortly before boiling, the last hop is added to intensify the fresh, fruity aroma that is the first thing our noses sense when enjoying a glass of Mühlen Kölsch.
During the subsequent three-day main fermentation, the top-fermented yeast processes the sugar obtained in the brewhouse into alcohol and carbonic acid. The beer is then transferred to the storage cellar for maturing. It is stored at a temperature of 0°C for at least 21 days in order to break down the base alcohols that were produced during fermentation, bind the CO2 that formed and develop its typical taste.
During the following filtration process, the last yeast cells remaining in the beer and other turbidity substances are removed. The stronger the filtration, the clearer the beer becomes and the longer its shelf life becomes. Our master brewer’s goal was to preserve as many flavoursome substances as possible in the beer. By using this gentle treatment to process the beer, it is merely filtered and not tortured. Although this does limit the shelf life of our Kölsch to 120 days, it creates the unique and unmistakable strong, malty and full flavour of Mühlen Kölsch.