A common way of preserving food and organisms is immersion in alcohol. But what causes alcohol to preserve these items well?
$\begingroup$
$\endgroup$
5
-
6$\begingroup$ As simple as it gets: bacterial life can't stand it, but we can. $\endgroup$– Ivan NeretinCommented Jun 27, 2016 at 14:37
-
$\begingroup$ But can't bateria not just leave the alochol or do they have to interact with it? $\endgroup$– MarijnCommented Jun 27, 2016 at 14:39
-
3$\begingroup$ @IvanNeretin I'd wager that we're actually much less resistant to alcohol. And it's a matter of scale. $\endgroup$– MithoronCommented Jun 27, 2016 at 14:41
-
4$\begingroup$ Of course it's a matter of scale; I never said it isn't. Throw a man in a tank with alcohol, and we'll see who's more resistant. $\endgroup$– Ivan NeretinCommented Jun 27, 2016 at 14:49
-
1$\begingroup$ Almost anything soluble in water will stop any kind of life if it is more than a few percent. Formaldehyde, acetone, acetaldehyde, NaCl ... $\endgroup$– KarlCommented Jun 27, 2016 at 19:18
Add a comment
|
2 Answers
$\begingroup$
$\endgroup$
7
Alcohol kills bacteria and fungus, put simply. It does this as its metabolism products cause damage directly to the DNA, and directly to the cell respiration process. It also happens to tend to dry it out.
We can drink alcohol safely because of our alcohol dehydrogenase enzyme, which breaks the toxic alcohol into useful byproducts, that we can use for energy.
Also, it's a matter of scale. Consider submerging yourself in alcohol for a period of time. Don't you think you'd probably die, too?
It's very important to note that alcohol strength matters in this case. It also depends strongly on type. For example, ethyl alcohol: we drink this kind. It's not as toxic as say, methyl alcohol, or isopropyl alcohol. Those last ones are used as preserving and disinfecting agents, respectively.
answered Jun 27, 2016 at 14:39
-
3$\begingroup$ It would be safe to assume that bacteria have pretty much all enzymes that we have, and many more than that. That's not what enables us to drink alcohol the way they can't. It is just that we are big, multicellular, and covered with skin. $\endgroup$ Commented Jun 27, 2016 at 14:47
-
4$\begingroup$ True. If we were submerged in alcohol, it'd wager it'd be very likely we'd die, too. $\endgroup$ Commented Jun 27, 2016 at 14:49
-
4$\begingroup$ So if we were submerged in alcohol we would die but are preserved very well? $\endgroup$– MarijnCommented Jun 27, 2016 at 18:31
-
-
$\begingroup$ The amount of blood alcohol that kills a human will not harm many single-cell organisms, at least not permanently. $\endgroup$– KarlCommented Jun 29, 2016 at 0:00
$\begingroup$
$\endgroup$
6
All life on earth is adapted to work in water, and only in water. The most basic level of life is enzymes producing proteins, and energy, to produce more enzymes. Cells, DNA, etc. are the directing structure for that.
In the wrong medium, e.g. 5% ethanol, the reactivity of the enzymes is totally off, not speaking of actual toxic effects of ethanol, acetaldehyde etc. One after the other of the thousands of chemical reactions, the equillibrium of which is life, take wrong turns and go into stalemate. And that is the end of it. The enzymes are no longer regenerated, what remains are all the membranes in the cells, which you can look at in your microscope.
-
2$\begingroup$ This answers the wrong question. It explains why things die in alcohol, but not why alcohol preserves anything, or why organic material is not dissolved to mush. $\endgroup$ Commented Jun 28, 2016 at 22:42
-
$\begingroup$ All life stops working in 20% ethanol. Bacteria, fungus, everything is back to very slow, non-biological, chemical decay. I call that preservation. ymmv $\endgroup$– KarlCommented Jun 28, 2016 at 23:03
-
1$\begingroup$ Sheeze dude. High alcohol tolerant yeast can withstand 25% ethanol. I know plenty of people who drink beverages well over 20% alcohol. Plus several forms of chemical decay result in complete obliteration which is anything but preservation. $\endgroup$ Commented Jun 29, 2016 at 3:12
-
1$\begingroup$ Gotta love peer review... Its makes great answers even better. $\endgroup$ Commented Jun 29, 2016 at 3:40
-
1$\begingroup$ Please enlighten me: What kind of fast chemical decay could happen to organic matter around room temperature? Lets say without adding larger amounts of strong oxidants, bases, acids, OK? And I said IN, not IN SHORT CONTACT WITH with 20% alcohol. 25%, if you wish. $\endgroup$– KarlCommented Jun 29, 2016 at 11:26