Imperial stout

The story exists in two versions. In one, the extra alcohol and hops had to keep the beer in good condition on the long sea voyage. In the other, the alcohol had to stop the beer freezing on the way.

Beer historian Ron Pattinson points out that regular porter was regularly shipped to the American colonies, a journey of more than double the length. In the 19th century porter of normal strength even went to India. His explanation: the beer was so strong because it was made for the rich drinkers at the Russian court.

Martyn Cornell, also a beer historian, calls the freezing story a new myth. If it had been cold enough to freeze the beer, the sea itself would have frozen over and the ships would not have got through. According to him the beer was strong 'because that's the way the customers liked it'.

There is a source from that time about how long the beer kept, though. In 1796 the painter Joseph Farington wrote in his diary that he had drunk porter from the London brewery Thrale's which, according to the giver, had been brewed specially for the empress of Russia and would keep well for seven years. That says something about the beer, but does not prove that the strength was meant for the journey.

What is right: in 1795 a history of a London church wrote that the empress of Russia repeatedly ordered very large quantities of porter, for herself and her court. In 1796 the painter Joseph Farington noted that he had been told that porter from the London brewery Thrale's had been brewed specially for the empress of Russia. That empress was Catherine the Great, who reigned from 1762 to 1796.

What is not right or is uncertain: the oldest 'Imperial' for beer that beer historian Martyn Cornell found is in a Scottish advertisement from 1821, for 'Imperial Porter'. In a price list from 1830, the big London porter brewers listed Porter, Stout, Double Stout and Imperial Stout, and for the ale they were going to brew also an Imperial Ale. 'Imperial' there evidently meant 'our heaviest'. Cornell found no conclusive proof that the word comes from the Russian court, although he does consider it likely. According to Cornell, 'Russian' only came to be added in the 20th century: in 1921 or 1922 the Barclay's brewery in Great Britain began selling a 'Russian Stout'.

Some brewery stories are not right at all. Beer historian Ron Pattinson debunks a piece of brewery advertising. In it, Tsar Peter the Great ordered the beer, but he died in 1725, when porter was hardly known even in London. And brewer John Courage is said to have perfected the style in 1787, while Courage only brewed its Russian Stout after 1969.

The Voedingscentrum (Netherlands Nutrition Centre) explains that THT ('ten minste houdbaar tot', best before) indicates until when a product is guaranteed to keep its proper quality. The advice: also use your senses after that date to judge whether something is still good. That is different from TGT ('te gebruiken tot', use by), which is about safety. The European labelling rules (Regulation 1169/2011) prescribe the wording 'best before …' (in Dutch 'Ten minste houdbaar tot …'), and drinks with 10 percent by volume of alcohol or more, according to those same rules, need not carry a durability date at all.

That the date is not a spoilage limit does not mean that beer does not change. According to the Brewers Association, beer begins to age after packaging: the bitterness declines, fruity and floral aromas can disappear and notes of cardboard, honey or sherry come in. The vast majority of beer is meant to be drunk as fresh as possible. Of weizen, for example, the BJCP writes that you drink it best young and fresh.

At the same time, a guide from CraftBeer.com (Brewers Association) names three groups that lend themselves to being laid down, a classification by Patrick Dawson, author of the book Vintage Beer: strong (in general from 8% alcohol), sour and smoked. Of Flanders oud bruin, a tart brown beer (not to be confused with the sweet Dutch oud bruin), the BJCP writes that the style is traditionally meant to be kept, and that examples with some age are considered better.

In short: after the THT, beer is usually not spoiled, but it is different. With hoppy beers often less fresh, with some strong or sour beers sometimes actually better.