I believe wine was mixed with water because it tasted better than plain water -- it had the positive side effect of killing bacteria.

But if no wine was available, was plain water drunk? Did people boil it first and if so why did they think that was a good idea?

I know at least one ancient thought that disease might be caused by invisible seeds, but I do not know how widespread this idea became or whether it was thought that boiling would affect those seeds.

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    Wine was diluted not because it made the water taste better, but because it made the wine taste better. See this question for more discussion on this myth.
    – SPavel
    Commented Jun 10 at 1:03
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    @SPavel That (really old) answer asserts that the whole idea that people drank beer because the water wasn't safe is a myth. Wine doesn't have enough alcohol to make water safe so it's kind of irrelevant here. There's also a lot of writing about the (Mayflower) Pilgrims and beer and reluctance to drink water, I think from original sources. Not sure how 'busted' that is.
    – JimmyJames
    Commented Jun 10 at 18:09
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    @JimmyJames We're discussing a 2000+ year old practice so the answers are going to be old ;) but I am referring to the discussion to draw OP's attention to the sources, rather than saying one of the answers already answers this question (in which case I would simply have closed as duplicate, instead).
    – SPavel
    Commented Jun 10 at 21:00
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    The Romans also knew that boiling grape juice in lead vessels makes wine taste better. Don't try this at home. Commented Jun 12 at 23:40
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    @SimonCrase I believe they added lead compounds directly as well. But is that any stupider than adding lead to gasoline and thereby poisoning every human and animal on the planet?? Many people alive today got major exposure, and I believe that lead is still present in soil near roadways, despite lead having been largely phased out.
    – releseabe
    Commented Jun 12 at 23:54

1 Answer 1


The Greeks and Romans did not have germ theory as we know, but they did know that boiling water purified it. The best attestation for this is found in Hippocrates, as mentioned in the Wikipedia article on water filters:

Hippocrates believed that water had to be clean and pure. Rainwater was the best water, but had to be boiled and strained before drinking to get rid of the "bad smell" and to avoid hoarseness of the voice. He designed a crude water filter to “purify” the water he used for his patients. Later known as the “Hippocratic sleeve,” this filter was a cloth bag through which water could be poured after being boiled.

The actual quote from Hippocrates is from De Aere Aquis et Locis 8:

Such waters are naturally the best. But they need to be boiled and purified from foulness if they are not to have a bad smell, and give sore throat, coughs and hoarseness to those who drink them.

That unboiled water in general can be unsafe can also be inferred from the strictures of Celsus on treating sick patients (3.23.7), who says that:

no water should be used for drinking unless it has been boiled.

Aristotle in his Meteorology mentions filtering seawater to make it drinkable, and describes well the purifying effect of boiling, but doesn't connect the two explicitly (since the book's concern is with meteorological phenomena, not sanitation.

I also see quite a few articles and books on sanitation/disinfection mention Aristotle mentioning disinfecting water explicitly, but none of them have a direct citation. They might have confused him with Hippocrates, or perhaps thought the evidence was more explicitly laid out than it really is.

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    It absolutely answers the question. Note that referring to rainwater he says "such waters are naturally the best. But..." I think we can safely infer that water which is less good (ie not the best) also should be boiled. Commented Jun 10 at 16:42
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    On how people might have discovered this without germ theory: Many harmful contaminants are easily perceptible by sight, taste, or smell, and it’s easy to discover (by accident or guesswork) that filtering and boiling can perceptibly improve these. (Anyone who’s been wild-camping can confirm this.) It’s a natural guess (under most theories of the mechanism, or just as trial and error) then that the boiling will also improve water that’s bad in less-obvious ways. Commented Jun 11 at 11:57
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    In general, foul taste is associated with harmful effects, because our senses of taste and smell evolved to help us distinguish good foods from bad. So it was natural for them to associate the improved taste of purified water with health benfits.
    – Barmar
    Commented Jun 11 at 14:29
  • Neither filtering nor boiling will remove the salt from seawater. That Aristotle guy would have been a lot smarter if he'd just googled that.
    – user121330
    Commented Jun 12 at 16:41
  • There's definitely a lot Aristotle got wrong. Logic will only take you so far if you've built your case on bad premises.
    – cmw
    Commented Jun 12 at 17:04

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