The output of German breweries dropped two per cent in 2013 on the previous year to the lowest level since German reunification in 1989, said the Destasis statistics office.
Shifting consumer tastes have seen brewers market ever more non-alcoholic as well as fruit-flavoured and other varieties, and bank on exports to China and the United States.
The total output of German breweries reached 94.6 million hectolitres last year, of which 79.7 million hectolitres or 84 per cent, were sold on the domestic market.
The German Brewers Federation blamed a long, harsh winter and an often rainy summer in 2013 for keeping Germans from guzzling lagers and ales in beer gardens and parks.
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But it also conceded that the slow downward trend was set to continue in the ageing country, which has long ranked near the top of the global list for per-capita beer consumption.
Federation chief Holger Eichele welcomed an "encouraging trend" of rising sales in the United States and China, as exports to non-European markets rose 8.7 per cent.
Germany's famed 500-year-old "Reinheitsgebot" or beer purity law mandates that the national beverage be made from only four ingredients -- water, hops, malt and yeast.
Europe's biggest beer producer, Germany has 1,300 breweries that now make about 5,000 different beers, says the federation.
German brewers last year applied to have the country's beer making tradition placed on the UNESCO list of the world's "intangible cultural heritage".