Yeast & Fermentation

Is Mahou top- or bottom-fermented? The Cinco Estrellas and Madrid's caña beer are bottom-fermented lagers. Bottom-fermented means the yeast works at low temperatures and eventually settles at the bottom of the tank, resulting in a clean, clear beer without fruity side notes.

In modern breweries, fermentation usually takes a week or longer, after which the beer matures cold in a lagering tank for several weeks. Breweries don't disclose exact times and temperatures for their brands, so all that can be said is that, in principle, it follows the same path as any pale lager from Pilsen to Munich.

A beer cellar carved into a mountain, as known in Franconia, isn't part of this story. Madrid's beer matures in large stainless steel tanks, and the cold comes from refrigeration equipment. That fits the city's history: the ice that Mahou produced on Calle Amaniel marked the beginning of Madrid's cold chain for beer.

After maturation, the beer is filtered until it's bright, meaning free of haze. Spanish lager is packaged cold and without yeast into kegs, cans, and bottles. Yeast-hazy beer is the exception and tends to come from the city's new small breweries.

In Madrid, cold is essentially the final step of fermentation, so to speak. A beer that flows straight from the tap into a chilled glass tastes clear and crisp, and it's precisely this crispness that gives the caña its appeal.