I believe in the middle ages and early industrial era it was common to drink alcoholic ciders that were only 2% ABV. Is something as low as 2% strong enough to kill pathogens? At an ABV that low does it take a few days to kill off most of the pathogens?
Whats the minimum ABV to make a beverage that is going to be safe from pathogens, excluding time? Or is there some kind of calculation involving time (like a beverage that is 0.1% ABV will become safe after 5 days, but one that is 40% will be safe in 20 seconds, etc)?
It’s not so much that lower-alcohol drinks kill off all the pathogens, but that when you make them, you heat them enough to kill everything, then add yeast, which eats all the sugars in the liquid and makes alcohol & CO2, then you put a cork in the bottle and there’s nothing for anything to grow off of any more. If you were to add some apple juice to some hard cider and let it sit out for a while, other, less pleasant things would start to grow in it.
Alcohol used for sterilization is also known as rubbing alcohol, about 180 proof.
To be fair, some things will get killed off by 5-10% alcohol, but just the wimpy ones. Something you’re more concerned about, like, say, salmonella or e coli? Not so much. There have been cases of people making mead with fruit that hadn’t been sanitized and ending up with lethally high levels of something growing in it, even with the alcohol.
AFAIK “rubbing alcohol” usually means isopropanol at various concentrations (quick market survey suggests most often 70% or 91% - I assume the 91% is an azeotrope at near atmospheric pressure), not ethanol. I’m not sure “180 proof” is meaningful as a descriptor of 91% isopropanol - it does not seem to be used that way.
Someone more expert in disinfection procedures can probably explain the different factors that argue for ethanol versus isopropanol for different conditions, surfaces, etc. I was moderately surprised to learn that for antibacterial action, 70% isopropanol is usually much more effective than 90% - the higher concentration induces reactions in bacteria that make them more resistant to the denaturing of the cell wall proteins, which is the main germicidal action of either isopropanol or ethanol.
“Fortified wine” was invented to add just enough alcohol to wine that it would be shelf stable. Barring exotically bred superbugs (some high alcohol beers are over 60% using specially bred yeast), your run of the mill bugs die somewhere between 16 & 20% alcohol.
Not that I doubt you, but why do you hold this belief? That seems awfully low to me. Most modern apples will have about one ounce of sugar in one cup of their juice, which would yield about 5-6% ABV. I admit these are modern cultivars that have been propagated artificially, but good-tasting (sweet) apples existed in ancient times, so I expect they existed in the middle ages as well.
But, even 5-6% ABV is not high enough to kill most bacteria. You specifically ask about pathogens, but non-pathogenic bacterial are also undesirable if they adversely affect the flavor (although, when it comes to alcohol, it is amazing how much some people can “acquire a taste” for what others consider foul-tasting). Acetobacterium convert sugars and alcohol to acetic acid (vinegar), while not pathogenic, is avoided.
To answer the OP, however, it is a combination of the alcohol content and the pH that prevents infections in fermented wines, ciders, and beer. Wines are commonly 12-14% alcohol while ciders and beer are closer to 5%, depending on the original sugar content. Wines and ciders will have a pH of around 3.5 and beer somewhere around 5. At these low pH levels, while some pathogenic bacteria may survive, they will not be growing much, so they are not harmful.
Wines do have a longer shelf life, due, in part, to the higher alcohol content. Ciders and beer is typically consumed soon after fermentation is complete. This is not because of pathogens, but because non-pathogenic infections will affect the taste.
But cooking apples and eating apples also still existed, so it’s possible that the demand for those uses took up all the relatively rare sweet apples and the cider and jack were made from the remainder.
I believe I heard that in the Prohibition documentary by Ken burns. I’m not sure where I heard it, however it was my understanding that in western nations we accidentally discovered that alcoholic beverages helped stop the spread of pathogens so these were drank.
As far as cans and bottles of modern beer, it is pasteurized and sealed in air tight correct? That wouldn’t be the case in the past, I thought the documentary said that people would just have an open barrel of cider they’d dip their cup into to get something to drink.
Well, no, cans and bottles of modern beer are not pasteurized. They are sealed air-tight, but that is to preserve carbonation as much as anything else.
And, I suspect, if you had a vat of apple cider that it would begin to ferment on its own fairly quickly, as the apples would have yeasts living on them and, particularly in the middle ages, they would not have done much to kill or get rid of the wild yeasts, since nobody had any idea that they existed. Considering the low pH of the cider, the absence of oxygen (fermentation only occurs in the absence of oxygen) and the large population of yeast cells, not much other than yeast would be growing in it. I also suspect that much of it was drank before the fermentation had completed, so the alcohol content would be below the maximum based on the sugar content.
I guess what I am saying is that the reason it was “safer to drink the beer (or cider)” is that the water was likely to have growing populations of the bacterium that cause Cholrea, Dysentery, Giardiasis, and the like. The process of making beer (boiling) would kill any of these that were present. In the case of cider, these organisms are not going to present in the apples and, even if introduced by a dirty cup or the like, they would not find an environment in which they would thrive. Not so much from the alcohol content, but the aforementioned pH and oxygen levels. I also suspect that much of the beer and cider drank in the middle ages was consumed while it was actively fermenting since there was no good method of preserving it and it would spoil quickly once the fermentation ceased (not necessarily due to pathogens, but less harmful infections that would ruin the taste).
Actually, a lot of beer in cans and bottle is pasteurized. The two main systems are pasteurization tunnels that heat the already canned product to the correct temp and hold it there and on-the-fly systems. Both of these systems are normally only used when refrigerated distribution lines aren’t available or when the supply lines are long enough that there is a high enough probability of growth between manufacturer and end user. IN the case of most breweries this is done when they grow to large regional size. For example New Belgium started pasteurizing their beer about the time they got distribution in to Nevada.
While the bacteria count can be quite low after boiling there is always some contamination during the rest of the process including canning its self which is why the tunnels tend to be the preferred way to go. Beer with high hops content can have longer distribution lines without pasteurization since it will retard the bacteria growth but at the end of the day the length of time between canning and drinking will determine if the risk of spoilage is high enough to drop $100K on a system.
Ah, yes. I had forgotten about the megabrews. I was not aware that New Belgium pasteurized their product. I’ve heard stories of people propagating yeast from commercial beer (Sierra Nevada Pale Ale, for one), which would not work if they had been pasteurized. Pasteurization is supposed to have a negative effect on the flavor; I am surprised to hear that New Belgium does it.
I do believe, however, that breweries that do pasteurize their beer do it only to improve shelf life (or, perhaps, to protect proprietary yeast strains) and not to prevent disease, as the bacteria that would spoil the beer is not likely to make one sick.
The point I was trying to make was in response to the OP, which questioned if the alcohol content of the ciders and beer in the middle ages was sufficient to kill the pathogens that were typically found in many water supplies of the time. The reason the cider, beer, and wines of the time would not make you sick while often the water would was not the alcohol content, but, rather, the production methods for producing these beverages was not favorable for the growth of the pathogenic organisms.
There’s at least one previous thread on this subject. I think there was a mention that certain water-alcohol mixtures were most effective because a mixture with too high of an alcohol concentration would not penetrate certain cell structures effectively.
In the case of beer (not sure about wine), the pH lowers pretty dramatically as well, going down an entire point from about 5 in the mash to about 4 for a finished beer. This puts it pretty squarely in the range where only acidophile bacteria do well, which is not coincidentally why most beer turns sour/vinegary as it goes bad.
So boiling the wort and fermenting it fairly fast creates a small alcohol content, lowers the pH, AND probably most obviously, consumes a lot of the nutrients available for most other microorganisms to subsist on.
So there’s a multiple-pronged reason that beer tended to be safer than water back in the day.
We know that 80 proof booze(40% ABV)- say vodka, is pretty much eternal if kept in a sealed container, so that’s an upper bound on the alcoholic percentage we have to consider.
And we know that wine (~14% ABV) will still spoil, so that’s a lower bound.
My guess is that it’s probably not much higher than 15%- that’s as high as you can generally ferment out to, before the alcohol inhibits the fermentation. So I’d imagine that the range of 15-25% where fortified wines are is probably the minimum we’re realistically looking at.
When I was working in beer (lo, these many years ago), Guinness pasteurized their export beer, and did not pasteurize their local product, making the local product different from the export product.
We didn’t use pasteurisation for our keg beer at the time. We and our customers didn’t use refrigerated trucks or cellars, and we had to give refunds on spoiled keg beer. We were moving to “internal spear” kegs to reduce spoilage.