Did you already know? Yeast makes the difference in beer

Did you already know? Yeast makes the difference in beer

Yeast plays an important role in the fine art of brewing beer. It converts the malt sugar dissolved in the wort into carbon dioxide and alcohol. Different yeasts are used. You determine the fermentation process. Three types of yeast are roughly distinguished - top-fermenting, bottom-fermenting yeast and spontaneous-fermenting yeast.

Top-fermenting yeasts need temperatures of 15 to 20 degrees to convert the malt sugar into alcohol. The yeast rises to the surface during the fermentation process. There it forms contiguous colonies and can be skimmed off. As long as there were no technical cooling processes, beers were made with top-fermenting yeasts almost everywhere in Germany.

Bottom-fermenting yeast needs temperatures between 4 and 9 degrees and sinks to the bottom of the kettle after fermentation. The fermentation process takes significantly longer than with top-fermented beer. Bottom-fermented beers can be enjoyed for a particularly long time.

Top-fermented beers include Kölsch, Alt and Weißbier. Today, around 85 percent of all German beers are bottom-fermented - including pilsner, export or even bock beer.

Spontaneous fermented beers play a comparatively minor role on the market. They do not contain yeast. Instead, yeast spores contained in the air stimulate the fermentation process in the open vat. The first brewers used this classic method when they did not yet know yeast. The best known spontaneous beers are Kriek, Gueuze, Lambic or Jopenbier.

Until Carl von Linde invented the chiller in the 1870s, bottom-fermented beer could only be brewed in winter. In regions with severe frost - in Bavaria and Württemberg - the brewers chopped ice from the water in January and used it to cool the fermentation tanks in deep cellars or caves. The stocks from the long winters lasted until the next cold season. While primarily bottom-fermented brewing began in these regions as early as the 16th century, the Rhinelanders developed particularly sophisticated top-fermentation techniques with their mild climate. Eva Neumann, aid

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