Diageo found creative ways to trim the price, by using local barley and sorghum, by putting the beer in big kegs rather than costly bottles and by inventing a cheap hand-pump to serve it.

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The rising prices of beer's main ingredients (barley for the drink, aluminium for cans) have cut margins slimmer.

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Dr Dahl says they had a diet of barley, which might have been crushed into a form of porridge, and they drank weak beer.

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We round off the visit tasting a couple of barrel-aged beers, the 2008 edition of 25 Dodici (25th December, their Christmas beer) and two barrels of Sedici Gradi (Sixteen Degrees, their strong, dark barley wine).

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