> The percentage of alcohol required to preserve beer for long periods is too high for sailors to be drinking a gallon of it per day.

Reading this thread I think the best thing would be if people were forbidden from comment on the history of beer in online forums. Nobody knows anything, yet everyone is shouting their misunderstandings from the rooftops.

The Danish fleet, to take just one example, was completely dependent on a supply of "skibsøl", to the extent that the king started his own brewery to ensure his fleet had a supply. Later kings started a stupid brewing monopoly system in Copenhagen to ensure no breweries went bankrupt, again with the same aim. "Skibsøl" was a big thing in Norway and Sweden, too. The Royal Navy used to serve it, too, before switching to grog.

Yes, weak beer will turn sour, but it takes a lot to make it harmful.