National Lager Day

What the day is

National Lager Day is observed on December 10. No origin for the observance has been documented. The style itself is the most widely drunk beer on earth.

Origin and background

What separates lager from ale is yeast and temperature, not color or strength. Ale yeast works warm and gathers at the top. Lager yeast works cold and settles at the bottom, and the beer is then held cold for weeks. The name comes from the German for storing, which is exactly what the method requires.

That cold conditioning began in Bavaria, where brewers stored beer through the summer in caves cut into hillsides and packed with ice, unknowingly selecting for yeast that tolerated the cold.

The genetics turned out to be remarkable. Lager yeast is not a single species but a hybrid, combining ordinary brewing yeast with a cold-tolerant relative that nobody could find. The missing parent went unidentified until 2011, when it was located growing on beech trees in Patagonia. How a South American wild yeast reached a Bavarian cellar remains unsettled.

The style most people picture arrived late. In 1842 in the Bohemian town of Pilsen, a brewer produced the first pale lager, using newly available pale malt and unusually soft local water. It was clear and golden at a moment when glassware was becoming affordable enough for people to see their beer, and it went on to dominate world brewing.

Lager is also the harder discipline. Cold fermentation is slow and produces a clean beer with very little flavor to hide behind, so any flaw in the process is plainly tasteable in the glass.

How to take part

• Try a well-made pilsner alongside a mass-market lager and taste what the extra time buys.
• Explore beyond pale: Munich dunkel, schwarzbier and bock are all lagers.
• Serve it cold but not ice cold, which mutes everything the brewer worked for.
• Check the packaging date. Pale lager is the style that suffers most with age.
• Drink responsibly, or mark the day with one of the many good alcohol-free lagers now made.