During last year’s sweltering summer in Europe, workers of the Störtebeker beer brewery stood at the doors of the bottle depot eagerly awaiting the empty returns so they could be washed and refilled as quickly as possible. A bottle shortage swept the country due to the rate at which beer was being consumed to quench the overheated nation’s thirst.

But it wasn’t the demand for their classic range of beers that surprised the brewery bosses most, rather the rate at which its alcohol-free varieties were being drunk.

“Sales were 40% up on the previous year,” says Elisa Raus of Störtebeker. “We literally could not produce it as fast as it was being drunk.”

Founded in 1827, Störtebeker, which is in the northern port city of Stralsund on Germany’s Baltic coast and built its reputation as a purveyor to holidaying royals, boasts no fewer than three non-alcoholic varieties among its considerable range of beers. Bernstein, a wheat beer, came out in 2007, then followed Frei, an isotonic pils, and the most recent, Atlantic Ale, last August. Its brewers are working on a fourth in their subterranean testing lab, but the details of that are secret.

Germany’s 1,500 breweries are said to produce between 400 to 500 alcohol-free varieties of beer. Photograph: Matthias Sandmann

According to the German Association of Brewers (DBB), now as many as one in 15 beers of the estimated annual 6.2 million hectolitres consumed in Germany contains no alcohol. This is being put down to an increase in health awareness as well as an improvement in the quality of a beverage with a reputation for being flat and tasteless, typically drunk only out of necessity.

“It’s no longer considered shameful to ask for an alcohol-free beer,” says Marc Oliver Huhnholz of the DBB. “On the contrary, it seems it’s even becoming something of an accepted lifestyle drink and the stigma is more or less gone.”

Germany’s 1,500 breweries, he says, now produce between 400 to 500 alcohol-free varieties of beer, with new ones emerging all the time as the brands compete to improve taste, head and consistency.

The growth in their popularity has even gone some way to stem a year-on-year fall in standard beer sales.

Improvements in both taste and variety and the fact that most bars in Germany will stock at least one type, says Huhnholz, “means that people are increasing enjoying alcohol-free beers out of choice”.

Alcohol-free types contain, like conventional beer, water, malt, hops and yeast and are brewed according to Germany’s 16th century purity law. The two most widely recognised brewing methods are an arrested or limited fermentation process and vacuum distillation. In the first, the fermentation process is stopped with a cold shock before the alcohol content is able to rise above 0.5%. This is how Störtebeker’s Bernstein is produced.

In the second, which applies to the Frei and Atlantic, after the completed fermentation process, the beer flows through a closed system and evaporates, with vacuum enabling the ethanol to boil off at a lower temperature. The flavour from the alcohol vapour is added back into the beer to retain its hoppy flavour.

Christopher Puttnies, chief brewer at Störtebeker, proudly shows off his gleaming Entalkoholisierungsanlage or de-alcoholisation facility, a 500-metre sea of twisting stainless steel pipes. It’s part of the brewery’s recent multimillion-euro investment programme and, says Puttnies, a reflection of its long-term commitment to alcohol-free varieties, which now make up one in 10 of the brewery’s sales.

“We evaporate it as slowly as possible so as to retain the taste as best we can – there’s a lot of technical fine-tuning involved,” he says. This way just 10 hectolitres of beer can be produced an hour, compared to 100 hectolitres for conventional beer. The factory turns out 50,000 half litre bottles of alcohol-free beer a day in addition to 450,000 bottles of its other beers.

Growth in the popularity of non-alcoholic beers has helped stem a year-on-year fall in standard beer sales in Germany. Photograph: Matthias Sandmann

Factory workers are allowed to drink the non-alcoholic beers as a refreshment during working hours. Increasingly, says Puttnies, the younger ones in particular even drink it off-duty at home. “It’s a far cry from the days when you wouldn’t be seen dead drinking a non-alcoholic beer,” he adds, recalling the first of its kind which was invented in communist East Germany in the early 1970s by a Berlin brewer. It was called AuBi (Auto Bier). “It was like dish water,” Puttnies says.

The number of German bars that are increasingly stocking one or more types of alcohol-free beer is on the rise. Only in Spain is the interest in it as high as in Germany. Though not everyone is convinced.

On Stralsund’s market square, where children seek relief from the mid-afternoon heat in a fountain, Peter Röscher sips a 5% ABV Weizen or wheat beer. The pensioner admits he has never been interested in trying new types of alcohol-free beer, having only ever drunk it “now and then” over the past two decades, “out of necessity, when I had to drive somewhere or had to get up early for work. I’ve always found it pretty thin and tasteless”.

His wife, Ellen, wonders what the point is. “You might as well drink water if you’re not going to drink the real thing,” she says.

But Rachel Hundt, sitting outside Cafe am Markt drawing on a non-alcoholic pils from a Bavarian brewery, says: “It’s just what I want in this heat. I like the slightly bitter taste and it might be psychological, but I get a buzz. I suppose it’s from the hops.”

Bianca Kison, a waiter, says: “I’d estimate that every fourth beer I sell these days is non-alcoholic. That’s a big change even from two, three years ago. Men, women, young, old, even kids like to sip it. There’s no typical customer.”