When did we stop diluting wine?

Question

In ancient Rome, wine was drunk diluted with water, as discussed in this question.

When did it become common practice not to dilute wine, but to drink it as is?

I tried to look, and found nothing much on diluting after the Roman Empire. I know monasteries made wine, but I don't know if they drank it diluted or not. There's a scene in The Three Musketeers where Porthos is a guest at a house, and is disgusted to be served diluted wine. So by that point, (or by the time Dumas was writing,) diluting wine with water was associated with poverty/stinginess, and wine was commonly drunk undiluted. But I have nothing in between those two points in time.

(Note this question is specifically about wine, rather than other alcoholic drinks, such as absinthe.)

Answer 1

I don't know the exact answer, but have the following conjecture.

In the old times water from many sources was not safe, and people did not know that one has to boil it to make safe. So they mostly drank wine (or beer, or vinegar diluted by water, as Roman soldiers did). Simply because there was no safe non-alcoholic beverages. If you drink only wine, you quickly became drunk. So wine has to be diluted. This also explains why they still drink diluted wine in some places in Europe. Because by tradition, in many places in Europe, wine is the main beverage. This tradition is preserved in some places in Europe, though of course nowadays many non-alcoholic beverages are available.

Once you have plenty of non-alcoholic beverages, or abundant clean water, you drink wine only for entertainment, so you can drink undiluted wine (is relatively small quantities).

Remark. Perhaps the comment of @congusbongus 5 is correct. But the fact remains that in many cultures people drank wine or beer as their main beverage. My friend came to small a Swiss village for vacation and rented a room with a local peasant. He asked the peasant: "Is water here safe to drink"? The answer was: "I don't know. I've never drank water in my life!"