The summer heatwave is causing serious problems in Germany: the country’s brewers are on the verge of running out of beer bottles.

The situation is so acute that one local brewer has issued an emergency appeal to drinkers, calling for them to return their empties.

“We need your help!” the Moritz Fiege brewery in the city of Bochum wrote on Facebook. “Great weather + great beer = serious thirst. The catch: although we regularly buy new bottles, we’re running out. So before you go on your summer holiday, please be sure to return your Moritz Fiege empties to your local off license. Make your motto: first the empties, then the holiday!”

Germans do not approve of beer cans. They like their beer in bottles. And, environmentally conscious as they are, they recycle. But beer bottles are not simply thrown in the recycling bin with the other glass.

Instead, every time you buy beer in Germany you pay a deposit of 8 to 15 cents (7p to 13p) a bottle. This is refunded when you bring the bottles back, and German supermarkets typically have long queues of people returning their empties.