Brewers have always known that the taste of their beer relies on their choice of malt, hops and yeast – but now Norwich scientists have finally proved the variety of barley has a big influence on flavour too.
Until now it was a widely-held belief that it was only the way barley is malted, rather than the barley grain itself, which contributed to the taste and aroma of beer.
But many brewers insisted that certain barley varieties did affect the flavour – and they have been proven correct following a five-year study involving The Sainsbury Laboratory at the Norwich Research Park, along with partners in the USA.
Group leader Dr Matthew Moscou said: 'It has always been very clear that hops and yeast will have a big impact on the flavour you get from the beer, but there was always this question of whether the variety of barley really mattered.
'The malting process directly impacts the wider profiles of flavour – how you get a pale ale, lager, or a porter – but what this study shows is that subtle flavour profile of the barley variety selected carries through that process.'
'Everything before has been anecdotal, but this study is the foot in the door to say there is actually something there. Now what we want to do is identify the genes which contribute to the flavour, and look at what kind of flavour profiles we can bring into modern barley breeding.'
Researchers cross-bred two types of barley, Full Pint from the US and Golden Promise from the UK, creating more than 200 lines which were harvested, micro-malted and scientifically micro-brewed into about 150 beers.
The beer was subjected to blind taste tests by a trained panel of about 20 people with sensitive palates employed by the brewing industry, who could detect the subtle variations between beers whose only variation was the type of barley.
Dr Moscou said while the taste of darker beers like porters were less affected by the barley choice, in lighter beers like pale ales the barley variety could influence the flavour by 10-20pc.
To test the hypothesis that environmental and climate factors – known in the wine industry as 'terroir' – affected barley flavour, the researchers also grew crops across three sites in Oregon, USA.
DNA analysis showed genes in varieties associated with flavour and genes associated with malting suitability were in separate parts of the barley genome. The study found that the genetic effect was larger than the environment.
'I was amazed at what we found,' said Dr Moscou. 'I am a geneticist, so if I cannot trace something to somewhere in the genome then I question whether we are testing something that has a real effect.
'This study has shown that the flavour profile has little to do with the malting characteristics. That's important because it says you can breed barley for malting – but you won't necessarily be breeding for flavour.'
The study findings concluded that: 'Barley varieties make different contributions to beer flavour, growing environment can have an effect, variety flavour contributions have a genetic basis and variety contributions to beer flavour develop during malting.'
BREWER'S VIEW
Brewer David Holliday, who runs The Norfolk Brewhouse in Hindringham, near Fakenham, said: 'I think this is a great endorsement of what is the key ingredient in any beer. Everyone knows the yeast and hops have a distinctive effect, but it is nice to have found that barley is no longer the poor relation.
'It is something I have always known in my heart, and to have it proven scientifically is very nice. We are a big advocate of Maris Otter barley, and this justifies our belief in our product.'
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