Preserving/Airtightening Foods with Argon?
in [Physics]
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From: J. Clarke on 2 Mar 2010 14:14 On 3/2/2010 12:39 PM, Salmon Egg wrote: > In article<hmid1r02p2c(a)news6.newsguy.com>, > "J. Clarke"<jclarke.usenet(a)cox.net> wrote: > >> "Arty farty wine drinkers" aren't the only people in the food industry >> to use argon as a preservative. > > Why is argon used? What is the primary advantage? I am not saying there > is anything wrong with using argon, just that it is unnecessary. The food processing industry has determined by experiment that argon works better than nitrogen for the purpose. The explanation I've seen is that it's denser and so more effective at displacing oxygen. Here's one example <http://pubs.acs.org/doi/abs/10.1021/bk-2003-0836.ch020?prevSearch=%255Ball%253A%2Bargon%2Bmeat%2Bpreservation%255D&searchHistoryKey=>. By the way, getting back to wine, there is a practical business reason for using an inert-gas preservation system. Looking at the prices at my local wine shop I see French wines going for anywhere from 9 bucks a bottle to 3000 bucks a bottle. Let's suppose you run a restaurant and decide that you can attract customers by offering a wide range of wines, including the very expensive ones, by the glass. Now, I don't know what the markup on that kind of thing is or what a restaurant would pay for one of those bottles, so let's say for the sake of argument that it's a 100 percent markup and they pay 1500 bucks for that bottle that retails for 3000. That's a 750ml bottle and a standard ISO tasting glass holds IIRC 50ml, so that's 25 glasses you can serve out of that bottle, so you might charge 120 bucks a glass. That's a price that most folks who would pay it at all would pay once for a special occasion, so for example Joe proposes to Jane and she accepts and they have a glass each to celebrate. So you open that bottle that cost you 1500 bucks and you serve two glasses out of it and you've got 240 bucks of income and a bottle that is almost certainly going to go bad before someone else comes along who is ready to pay 120 bucks for a glass of wine. End result for you is a net loss of 1260 bucks. The solution to this is to mount the bottle in a commercially available dispensing system that flushes the air out of it and fills the airspace with argon, so that bottle keeps indefinitely (remember, while sealed it would keep for decades) and you can continue to sell glasses from it occasionally until it is empty. The cost of the argon in that context is peanuts. Nothing artsy-fartsy about it, hard-headed business sense. Now, I know you've mentioned botulism, but that is not an issue with wine--between acidity and alcohol that particular organism doesn't have a chance of surviving in a wine bottle. Neither does salmonella. The microbe that destroys wine is a bacterium that metabolizes ethanol into acetic acid and it needs oxygen to do that, so the inert gas fill blocks that action--if it fails the result is a bottle of very expensive not very good quality vinegar, which is harmless.
From: Salmon Egg on 2 Mar 2010 21:05 In article <hmjp0c01sm0(a)news4.newsguy.com>, "J. Clarke" <jclarke.usenet(a)cox.net> wrote: > Now, I know you've mentioned botulism, but that is not an issue with > wine--between acidity and alcohol that particular organism doesn't have > a chance of surviving in a wine bottle. Neither does salmonella. The > microbe that destroys wine is a bacterium that metabolizes ethanol into > acetic acid and it needs oxygen to do that, so the inert gas fill blocks > that action--if it fails the result is a bottle of very expensive not > very good quality vinegar, which is harmless. I am still skeptical. What detrimental chemical reactions take place when nitrogen were to be used instead of argon? I cannot conceive how flushing once with argon is going to be more effective or cheaper than flushing twice with nitrogen. Bill -- An old man would be better off never having been born.
From: dlzc on 2 Mar 2010 21:11 Dear Salmon Egg: On Mar 2, 7:05 pm, Salmon Egg <Salmon...(a)sbcglobal.net> wrote: > In article <hmjp0c01...(a)news4.newsguy.com>, > "J. Clarke" <jclarke.use...(a)cox.net> wrote: > > > Now, I know you've mentioned botulism, but that is > > not an issue with wine--between acidity and alcohol > > that particular organism doesn't have a chance of > > surviving in a wine bottle. Neither does salmonella. > > The microbe that destroys wine is a bacterium that > > metabolizes ethanol into acetic acid and it needs > > oxygen to do that, so the inert gas fill blocks that > > action--if it fails the result is a bottle of very expensive > > not very good quality vinegar, which is harmless. > > I am still skeptical. What detrimental chemical > reactions take place when nitrogen were to be > used instead of argon? I cannot conceive how > flushing once with argon is going to be more > effective or cheaper than flushing twice with > nitrogen. Oxygen concentrators are equally effective at concentrating oxygen and argon with the same zeolite. They are the same "size". Mechanically, if argon is in the way, maybe oxygen has a harder time migrating through seals... David A. Smith
From: Salmon Egg on 3 Mar 2010 12:25 In article <2eecc38c-2f43-4942-a50d-79f53e35771a(a)k36g2000prb.googlegroups.com>, dlzc <dlzc1(a)cox.net> wrote: > Dear Salmon Egg: > > On Mar 2, 7:05�pm, Salmon Egg <Salmon...(a)sbcglobal.net> wrote: > > In article <hmjp0c01...(a)news4.newsguy.com>, > > �"J. Clarke" <jclarke.use...(a)cox.net> wrote: > > < > > > I am still skeptical. What detrimental chemical > > reactions take place when nitrogen were to be > > used instead of argon? I cannot conceive how > > flushing once with argon is going to be more > > effective or cheaper than flushing twice with > > nitrogen. <snip> > Oxygen concentrators are equally effective at concentrating oxygen and > argon with the same zeolite. They are the same "size". Mechanically, > if argon is in the way, maybe oxygen has a harder time migrating > through seals... > > David A. Smith I can understand the rationale for such rationalization but that is not the same as being factual. I do not know what the size of an argon ATOM is compared to that of an oxygen ATOM. I would expect them to be about the same size. An oxygen MOLECULE, however, being diatomic is probably longer in one direction. But if nitrogen or argon purges out the oxygen, why would argon preserve better? Is a puzzlement. Bill -- An old man would be better off never having been born.
From: Michael Moroney on 4 Mar 2010 23:01
Salmon Egg <SalmonEgg(a)sbcglobal.net> writes: >In article ><2eecc38c-2f43-4942-a50d-79f53e35771a(a)k36g2000prb.googlegroups.com>, > dlzc <dlzc1(a)cox.net> wrote: >> Oxygen concentrators are equally effective at concentrating oxygen and >> argon with the same zeolite. They are the same "size". Mechanically, >> if argon is in the way, maybe oxygen has a harder time migrating >> through seals... >> >> David A. Smith >I can understand the rationale for such rationalization but that is not >the same as being factual. >I do not know what the size of an argon ATOM is compared to that of an >oxygen ATOM. I would expect them to be about the same size. An oxygen >MOLECULE, however, being diatomic is probably longer in one direction. >But if nitrogen or argon purges out the oxygen, why would argon preserve >better? Is a puzzlement. I would suspect that the best gas (for the wine) is to emulate as closely as possible whatever the gas at the top of a well-sealed well-aged bottle of wine is. It would be neither argon nor nitrogen, but probably mostly carbon dioxide. |