We used to drink 2-4 times as much alcohol in the past

From When did people stop being drunk all the time? by Lefineder.  The subheading is Trends in alcohol consumption from the middle ages to the modern world tell a story.

Information packed.  

The English, said Sir John Fortescue (c. 1470), "drink no water, unless at certain times upon religious score, or by way of doing penance.", looking at reconstructions of beer consumption from the middle ages to the pre-industrial era this was only a slight exaggeration. When estimating consumption from the amount of beer provided to soldiers, convicts, and workers or reconstructing consumption from tax revenues on beer we see that the average person consumed about a liter of beer a day, this is around four times as much as consumption in modern beer-drinking countries.

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Since modern consumption of alcohol is more diverse, let us put the historical consumption of wine and beer in terms of pure alcohol and compare it to latter rates of alcohol consumption1. When this is done we see that consumption of pure alcohol was at least 2-4 times higher in the past.

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Click to enlarge.

Society is transformed in several ways, Whereas beer expenditure used to consume 12.5% of people’s salary in 1734 in the 1800s it consume only 1-3%. In the English poll tax of 1379-81 we can see that a total of 2.5% of the medieval workforce is comprised of brewers, in 1841 this is reduced to only 0.3 of the labor force.

The answer to the headline question is circa 1800.

The reason for heavy beer consumption has usually been advanced from a health side - water spoils whereas the alcohol in beer keeps down the pathogens.

I have always wondered, though, whether pain control might not also have been part of the answer.  This is especially the case with sailors who were subject to punishing workloads and injuries anad yet kept chugging along.  Being half drunk might actually have been beneficial.