> 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.

Ever gotten a bad case of gastroenteritis from a restaurant that made you swear never to go back and even turned you off an entire style of cuisine for, at least, a little while?

A few brushes with bad water might have given folk a strong preference for beer, just to be on the safe side, even if most water was safe.

Often things that a lot of people do repeatedly for "pure enjoyment" actually has some hidden benefit.

Like for instance, drinking in general. People do it because it's fun, but it can play an important social bonding role.

Point of order, beer was stored in a higher alcohol percentage (which is where we get IPAs from) which does extend its shelf life significantly. The gallon was heavily watered down to serve.

Which is basically identical to lite beer we drink today. Hopefully with more flavor, but I don't actually know.

As a general statement about Europe or the UK that's completely impossible. There wasn't enough cider for it to be more common than beer. We also know beer was the most common (then later grog, at least for the navy).

This might be true for some specific region or subset of ships, though.