BERLIN - In a microbrewery in a trendy Berlin neighbourhood, Thorsten Schoppe, one of a wave of beer-makers using new German ingredients to create non-traditional brews, pours hop pellets into a copper vat.
"We only use four ingredients, and that's one of them," said Schoppe, as the faintly sour scent of beer emanated from the boiling water and malt, "so they're important".
German small-batch brewers like Schoppe have increasingly used so-called "flavour hops" to impart notes of orange, grapefruit or peach while still following the country's cherished 16th century purity law, which restricts other flavourings.
Until recently, Schoppe had to import special hops from the US, where craft brews have an established niche in the market.
This year, German growers, moving to capitalise on growing demand, harvested the country's first commercial-sized batch of newly developed flavour hop varieties.
"It really amazes people what kind of special flavours you can bring to a beer even within the Reinheitsgebot (the purity law)," said Schoppe, who brews a double India pale ale with a citrus aroma under his Schoppe Braeu label.
"Some people don't believe you if you say this is all natural, they think you must have added some flavours," said Schoppe.
Sebastian Hiersick, 35, a cook in Berlin, is a whisky drinker who generally doesn't like "normal German beer".
"It's either too hoppy, too malty, or too carbonated," Hiersick said. After starting to work at a restaurant that sells German craft beers, he developed a taste for those with fruity undertones.
"When it's hot out, or in the summer, they are really nice to drink. They are very drinkable, it's like juice or lemonade," Hiersick said.
Colleague Magdalen Reskin, 29, who likes chocolate bock, a dark brew, agrees.
"I like them because they don't taste like beer," she said.
Hops, fresh or dried and processed into pellets, traditionally gave beer its bitter taste.
Hop breeder Anton Lutz began developing the new German varieties in 2006, when he stopped throwing out seedlings with "fruity" aromas and started breeding them on purpose.
Working out of the Hop Research Centre in Huell, a tiny village 60 kilometres (40 miles) north of Munich, Lutz pollinated female flowers from a popular US hop variety, called Cascade, with pollen from male plants from traditional German hops.
The idea, said Lutz, was to combine citrus North American hop flavours with traditional local hops to create a flavour that is "hoppy and fruity, not only fruity".
"German beer drinkers expect beers that are not so extreme, so we needed something a little bit softer," Lutz said.
The four new breeds, including one called "Mandarina Bavaria", are described as having notes of "distinct honeydew melon" and "strong tangerine and citrus".
Local growers are starting cautiously: by the end of 2013, 150 hectares, less than one per cent of Germany's hop fields, were expected be planted with the new varieties.
"We don't want the whole beer-drinking culture in Germany to change," Lutz said.
"We want to open up beer to new markets, not convince people to change their tastes."