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Chestnut trees and chilled beer

Are you, too, already looking forward to the summer and the beer garden season it ushers in? Personally, I can hardly wait! I just love this (Bavarian) tradition, sitting together with friends and relishing a cold draught of good chilled beer! Talking of chilling: this used to pose such a challenge that King Ludwig I even prohibited the brewing of bottom-fermented beers in summer. Brewing was permitted only in the winter months from Michaelmas Day (29 September) to St.George’s Day (23 April).

The reason for this was the absence of an option for cooling the beer down to four to eight degrees during the brewing process. For bottom-fermented beer, which had always been very popular, you see, chilling is mandatory during maturation and storage: if the ambient temperature rises to above ten degrees, it spoils. But it would have gone against nature if the brewers back then had not managed to deal with the problem.

At the sloping banks of rivers, caves of up to twelve metres in depth were dug, and filled with natural ice, laboriously hacked in winter from rivers and lakes. More or less on the motto: “Fill your cellars up with ice, and all your beers will turn out nice!” But what if there was a hot summer and even the deep cellar warmed up? As a precaution, shady chestnut trees were planted on top of the cellarage caves.

Chestnut trees. Does that sound familiar? 😉 The typical beer garden had thus been born. Back then, too, people came there to meet up and savour a nice cold pint. They brought their food with them – something that’s still possible in some beer gardens today.

But if the weather conditions in winter were unfavourable, the prices for ice soared to amazing heights. The 17 breweries in Munich back then, you see, consumed an unbelievable 56,000 tons of ice a year. This was not sustainable as a long-term option, not least because there were repeated problems involving hygiene. Containers filled with ice were suspended in the fermenting tub, so as to cool the liquid – but quite often the germ-ridden ice leaked out and the beer went bad.

Fortunately, there was Carl Linde, who resolved to put a stop to these difficulties once and for all. As a mechanical engineer, he was interested in artificial refrigeration, and invented the Linde refrigeration machine. Large breweries seized the opportunity, and industrialised their brewing processes with this compression chiller – a genuine revolution in the history of brewing.

The leviathan weighs almost six tons, is 2.40 metres high and 5.30 metres wide. Incredible, isn’t it? If you’re just as interested in this as I am, then as from June 2019 you can see it up close in the “House of Bavarian History” in Regensburg. In five large individual parts, it was hoisted a few weeks ago into the first floor and onto the “Bayern industrialisiert mit Maß” (Bavaria’s prudent industrialisation) stage. Drop by to have a look, and marvel at the machine to which our forebears owed the capability to ensure an adequate supply of beer all the year round.

Photo: Haus der bayerischen Geschichte

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