Image copyright Getty Images Image caption Beer is a serious business in Germany, and there is a strict limit on what ingredients can be used

Eric Toft is on a mission to improve German beer - which is odd because he's an American.

All the same, Mr Toft, the head brewer of a tiny brewery in Bavaria, in the south of the country, politely preaches that Germany's beer-makers should be more adventurous.

In a nation very proud of its beer, he is an outsider who thinks the natives could do better.

Not that Mr Toft looks like an outsider. With his curly fair hair, and the fact he almost always wears lederhosen - the traditional Alpine leather shorts - he could pass for a Bavarian.

For a lot of brewers, [the law is] an easy excuse to say, 'I can't think outside the box, so we'll carry on business as usual' Eric Toft, Brew master, Schonram brewery

Mr Toft, who first went to Germany to study brewing and ended up staying, is brew master at the 234-year-old Schonram brewery, based in the village of the same name near the border between Germany and Austria.

He is passionate about beer, and although he works within the constraints of the Reinheitsgebot, the country's beer purity law, in addition to more traditional German brews he makes British-style beers, such as India Pale Ale (IPA).

While such a state of affairs may make many Germans cough into their helles or dunkel lager, Mr Toft says other smaller German brewers should also explore new flavour possibilities while not breaking the law.

After all, sales of his newer recipes are rising strongly, at a time when overall beer consumption in Germany is now at a 20-year low.

Unesco appeal

The Reinheitsgebot was first applied to Bavaria in 1516, before subsequently covering the whole of Germany from 1906. In its original text, the law stipulated that beer could only be made from water, barley and hops.

Image caption Eric Toft brings a cross-cultural approach to his brewing in the German village of Schonram

Yeast was later added to the list when its vital role in brewing became understood, and wheat was subsequently also allowed.

Yet the practice in other countries of adding cheaper ingredients to beer, such as rice, maize, and sugar is forbidden. As is fruit, which is often added to Belgian ales, or - heaven forbid - anything artificial.

So revered is the Reinheitsgebot that the German Brewers' Association applied in December of last year for the United Nations Educational, Scientific and Cultural Organization (Unesco) to give it protected "world heritage" status.

It used to be that Unesco only accorded monuments and other physical sites World Heritage status, but recently it's been widened to include "intangible" treasures.

The tango dance and French cuisine are already on the list, and the German brewers want the Reinheitsgebot to follow suit.

Marc-Oliver Huhnholz, spokesman for the German Brewery Association, says the law means that when people drink a German beer they know it is "absolutely pure".

"We made a survey [in Germany], and asked people if they wanted to have beer brewed under the purity law, and more than 90% said they wanted to stick to the purity law.

"There are some things that Germany stands for and one of them is German beer... we want to show the world that we have a very old tradition."

Image copyright Reuters Image caption Newer varieties of hops, especially those from the US, can give beers distinct fruit flavours

But there is no doubt the Reinheitsgebot is also a constraint. As already mentioned, it means German breweries cannot flavour their beer with fruit, something their counterparts in Belgium routinely do to much acclaim.

At a time when sales of beer in Germany continue to fall, Mr Toft thinks the ancient regulations make many German brewers believe - wrongly in his mind - that they have to keep to the same old ways, and the same old beers.

"For a lot of brewers, it's an easy excuse to say, 'I can't think outside the box, so we'll carry on business as usual,'" he says.

"But, actually, the Reinheitsgebot ought to be an incentive to be creative, because we are forced to think of ways of making different flavours within the law."

Popular with women

Salvation comes in the main from the not-so-humble hop flower, which gives all beers a level of bitterness.

Traditional German beer styles Helles - pale lager from southern Germany, low in hops Pils - a version of the lager that originated in the Czech city of Pilsen; has a higher hop rate than helles Dunkel - a dark lager made using barley malt that has been roasted for longer Wheat beer - as the name suggests, this uses wheat in addition to barley Kolsch - a pale ale from the city of Cologne Altbier - meaning "old beer"; a copper-coloured ale from Dusseldorf

While most hops grown in Germany are mild and subtle ones used for making lager, hops from the UK - and especially the US - can also impart a distinct fruitiness to beer, with flavours like orange, grapefruit, and peach.

Such fruity hops are now starting to be grown in Germany, and mean that brewers such as Mr Toft can increasingly produce brews that taste more like a British real ale or American craft beer.

The result is that sales of the new fruitier beers are selling very well, especially among women, and that they have discovered new foreign markets.

Mr Toft says: "We found these beers appeal to women who previously claimed they didn't like beer. And from that, it's become popular with their husbands."

He is also successfully marketing the beers to young people in Italy.

Thorsten Schoppe, owner of the Schoppe Braeu microbrewery in Berlin, is using fruity hops to brew strong American-style craft ales.

"In Belgium they produce cherry beer," he says.

"If you produced it in Germany you would have to call it 'alcoholic beverage made with cherries', and that wouldn't be a beer. You have to write that on the label."

Image copyright Getty Images Image caption German beer is famous around the world for its purity

While Mr Schoppe says most people in German are pleased with the Reinheitsgebot because it means they don't have "rubbish" or "artificial chemicals" in their beer, he says it does limit small breweries that want to be creative and stand out from the crowd.

In the past he has experimented with adding things such as herbs, honey, cinnamon and chilli to beer - all unacceptable in Germany.

But at Schoppe Braeu Mr Schoppe is conjuring up new flavours, and higher sales, while sticking to the brewing law.