Toxic foil capsules revisited

Taking up a point that came up in the recent "lead crystal" thread:

If you're concerned about this, you should be still more concerned to wipe off (wetting a cloth or paper napkin) any crystals found between a foil capsule and the cork, after a wine has been stored.

Lead foil capsules have been off the market since the early 1990s.

Something's wrong here. Mark Lipton might have something to say about it. The reason I raised the point originally is that I continue to open wine bottles younger than that and find capsules of soft dense metal foil, bare inside -- clearly not aluminum. I'd assumed they still used a lead alloy, but Robin indicated otherwise. Problem: other metals I can think of that are both soft and heavy are also toxic when dissolved by acid foods (i.e. wine). Tin seemed a candidate if the lead is gone. I checked some toxicities in the standard reference every good home library has (the Merck Index) and soluble tin compounds are similar to lead in animal lethal dose (though the toxicity or accumulation mechanisms may differ). It leaves me wondering if reports of this issue's resolution are premature.

(Reminds me of a case in the semiconductor industry where locals were anxious over use of Arsine as a dopant gas for silicon wafers. Arsenic is famously poisonous and Arsine is the ammonia analog containing Arsenic in gaseous form. The locals were placated by the news that only Phosphine gas would be stored henceforth, no Arsine. Phosphine contains Phosphorous, perceived as more benign -- Phosphorous is an essential nutrient . Yet the reality is that Phosphine gas is nearly as toxic as Arsine.)

[Robin Garr]

It leaves me wondering if reports of this issue's resolution are premature.

In the real world, I doubt it. First, lead stands alone as a public-health policy issue. We rarely see fund-raising drives to rid our garbage dumps of tin cans.

More seriously, however, the whole lead-capsule issue strikes me as more than a little bogus. Lead capsules were used, I would assume, from the late 18th century (when wine bottle corks came into wide use) until the 1990s. I'm not aware of any reports of lead health issues - cumulative or acute - associated with capsules. The capsule is peeled off or cut away, and every wine enthusiast I've ever seen will wipe off the bottle neck before pulling the cap and pouring. Even without autoclaving, it's hard to imagine a significant number of lead molecules remaining to be washed into the glass with the first pour.

And again, no reported incidence of lead issues. Contrast this with the abundance of evidence regarding lead paint and the inferential data associated with leaded gasoline.

This whole thing strikes me as the work of nanny types with too much time on their hands, and I'm not prepared to sign on to a battle against tin capsules. Except maybe because of the more legitimate threat that they can cut hell out of your hands if you're not careful.

Robin, my company was involved in the lead issue in the 1990s. The issue with lead closures was less a consumer than a worker issue -- the unions led the charge in that area. One of the consumer related arguments dealt not with wine drinkers, but with disposal of the closures -- kids, land fills, stuff like that.

Consumer advocates were important in lead paint and lead in gasoline, of course, and in the China lead paint issue, still leading the charge.

I've got a history of the various battles over lead tucked away somewhere if you would like more details.

Regards, Bob

In the real world, I doubt it. First, lead stands alone as a public-health policy issue. We rarely see fund-raising drives to rid our garbage dumps of tin cans.

More seriously, however, the whole lead-capsule issue strikes me as more than a little bogus. Lead capsules were used, I would assume, from the late 18th century (when wine bottle corks came into wide use) until the 1990s. I'm not aware of any reports of lead health issues - cumulative or acute - associated with capsules. The capsule is peeled off or cut away, and every wine enthusiast I've ever seen will wipe off the bottle neck before pulling the cap and pouring. Even without autoclaving, it's hard to imagine a significant number of lead molecules remaining to be washed into the glass with the first pour.

And again, no reported incidence of lead issues. Contrast this with the abundance of evidence regarding lead paint and the inferential data associated with leaded gasoline.

This whole thing strikes me as the work of nanny types with too much time on their hands, and I'm not prepared to sign on to a battle against tin capsules. Except maybe because of the more legitimate threat that they can cut hell out of your hands if you're not careful.

I don't believe that "tin cans" these days are lined with tin.

I agree that any lead residue on the lips of wine bottles due to lead capsules does not represent a health hazard. But I do think it's a good thing not to have the lead capsules ending up in waste dumps after they're discarded. Especially since more environmentally friendly alternatives as capsule materials exist.

Or even no capsule at all. If I recall correctly, the original reason for having a capsule over the cork was to prevent its being gnawed at by rodents. How many of us have a mouse problem in their cellar these days?

-Paul W.

I remember that we looked at a number of studies; here's one that is one still online from Switzerland showing 12% higher levels of lead in the blood of imbibers than abstainers, and fairly high levels of lead in wine. I may not have been permitted the other sources -- it was a fairly hefty brief by the time we got our ducks in order and the issue was resolved in our relatively little world by other means.

http://www.springerlink.com/content/j74r3x308r03h615/

Regards, Bob

Please understand the specific issue I refer to here (raised originally in the earlier thread). Ullage past a cork interacting with metal foil for years leads to salt crystals, often white, that can contain lead acetates, tartarates, etc. from the acids in the wines. These organometallic salts are readily assimilated by humans; if you ever worked with them in pure form in a laboratory and read up on their material safety data (I have done both), the special health warnings about them will be familiar. (Lead acetate from pewter cups is even associated with toxicity in ancient Rome -- the implication of orgies helps to keep that story alive.) I'd reckon offhand that the lead in a few tens of milligrams of under-the-foil crystals far exceeds what we're hearing about now in paints on recalled toys and is also more easily assimilated. Therefore I've long wiped such crystals with a damp cloth when encountering them. This has nothing to do with battles against tin capsules, only with whether wiping off the crystals is important.

If quantitative toxicity is similar in tin or other heavy-metal salts (in the case I looked up, it's actually three times worse than lead), this may not be something to discount out of hand. Certainly not in comparison to leaded glass, whose lead is far less soluble. The real world vs. complacent perceptions is precisely why I raised the point.

I'm still looking for further expert comment here (thank you Bob) since some readers deal with related matters professionally.

I had one bottle of wine that had been bottled without any cork. The lead capsule had no holes and the wine was such that the sediment and viscous liquid part that may have seeped out at first sealed the bottle so that nothing leaked out even though it was stored on its side for 20 years.

Unfortunately I couldn't convince SWMBO to taste it to see if this unusual treatment had affected the taste - silly woman was afraid of contracting a rampaging case of plumbism......

I was astounded to see absolutely no sign of a cork, I can tell you!

[David M. Bueker]

The soft metal in use since the '90s is not lead. I'll be darned if I can remember what it is, but it's been discussed in the past, so if the old board archives were not lost to history it might still be there.

It's tin.

Tin is also used to line copper pans. Max, are you saying that the salts are toxic, not the tin itself? Otherwise...

I don't know if aluminum is used much any more, it tended to make a knife-edge when you cut it.

Max, are you saying that the salts are toxic, not the tin itself?

Yes, I'm sorry if that was unclear. (Actually I didn't say it, the Merck Index did; I just reported it).

This thread has recalled a sense of déjà vu. 15 years ago (without even the factor yet of lead being absent), I mentioned to a French-émigré co-worker the practice of wiping off metal salts formed under capsules in aged wines, which seemed an obvious and easy safety precaution. He laughed this off as the sort of foolish concern typical of American consumers. Then an authoritative report came out (I'm not sure where, at this point, but it may have been from Europe) warning about a health hazard from accumulated lead salts if not removed.

More seriously, however, the whole lead-capsule issue strikes me as more than a little bogus. Lead capsules were used, I would assume, from the late 18th century (when wine bottle corks came into wide use) until the 1990s. I'm not aware of any reports of lead health issues - cumulative or acute - associated with capsules. The capsule is peeled off or cut away, and every wine enthusiast I've ever seen will wipe off the bottle neck before pulling the cap and pouring. Even without autoclaving, it's hard to imagine a significant number of lead molecules remaining to be washed into the glass with the first pour.

I'm afraid that you're off base here, Robin. The reason lead capsules were removed from use is that lead can -- and did -- accumulate in significant quantities in some people who drank wine. The problem with heavy metal toxicity generally is that it's a chronic condition: lead accumulates in the body and tends to stay put for the long term. That's why lead paint is so dangerous in houses. Even though the exposure is pretty small, on a day-to-day basis it can accumulate to dangerous levels. Regarding your point that the amount of lead would be minimal, that would be true if it were only in the crust on the rim of the bottle. However, lead acetate is pretty soluble in wine, so when the cork seal is imperfect (as is often the case with older wines, the wine can actually dissolve lead from the capsule. Even so, the exposure levels aren't huge so the health issues are fairly subtle. (You never hear the expression "mad as an oenophile" for instance) Lead exposure is most dangerous in children and pregnant women, neither of whom should be drinking much wine in the first place.

Getting back to Max's question, I too have noticed capsules in post-'90 wines that are neither aluminum nor plastic, but are instead made of a fairly soft but dense metal. I've assumed that it was tin or a tin alloy. Although tin also has toxicity issues, most of the problems arise with organotin compounds such as various trimethylstannanes. I'd guess that reaction with wine would convert tin to stannous acetate or stannous tartrate, neither of which poses a very prominent health hazard. I'm wiping the crust off of my bottles, though.

Mark Lipton

I guess there's little dispute that wiping any crystals from dissolved capsule metal, whatever it is, is reasonable.

Mark, I've noticed that these crystals seem to effloresce, like soluble minerals from rock. (Recall a famous story from Poe, the one with wine -- Montressor tells Fortunato to "feel the nitre on the walls -- we are under the river now ...").

What got me raising the issue of tin is that the standard source I cited gives mouse LD50s (50% lethal dose concentrations, if anyone wonders) for soluble lead salts, including lead acetate, around 200 mg/kg while the identical measure for soluble stannous salts is circa 66 mg/kg -- three times "more poisonous." But I also notice that lead acetate is listed as a carcinogen; the tin salts have no such annotation. (My earlier point about different toxicity mechanisms.) I'd long understood -- wouldn't have raised this issue, otherwise -- that soluble heavy-metal salts in general are healthwise "bad news." (IIRC, one ingredient in the old pharmaceutical "universal antidote" was tannic acid, specifically because it binds up soluble heavy metals, as anyone will remember if they had a space-race era chemistry set and made iron ink. That might even be a benign factor in wines, if they're not too old, eh?)

[David M. Bueker]

When all is said and done - wiping the rim of the bottle is something I do pretty routinely anyway, as the bottles (especially Gemran wines) get pretty nasty over time, despite careful storage and all other precautions. So for doing something aesthetically pleasing I get added safety benefits.

What got me raising the issue of tin is that the standard source I cited gives mouse LD50s (50% lethal dose concentrations, if anyone wonders) for soluble lead salts, including lead acetate, around 200 mg/kg while the identical measure for soluble stannous salts is circa 66 mg/kg -- three times "more poisonous."

OK, this is a bit confusing. I see that LD50, which is for stannous chloride. However, as you probably know, stannous fluoride (aka Fluoristan) has been used for generations in toothpaste. How to reconcile? Firstly, the LD50 is for intraperitoneal administration in mice, so either 1) oral toxicity could be vastly reduced or non-existent or 2) mice != humans (it wouldn't be the first time that that complication arises; sometimes even mice and rats show markedly different responses). FWIW, I see no other toxicity data for other tin salts, so there might be something special about SnCl2. In fact, stannous oxide is an essential nutrient, with a recommended intake of 10-20 mg/day. Weird...

Mark Lipton

Today I think a lot of the foils are made of a laminate of thin sheets of both metal (tin and alum) and plastic. Some have a seam and these could “fall apart” and getting them totally off the bottle can be very difficult. Others don’t have a seam and the way the different laminates (metal and plastic) are layered makes it almost impossible to separate them, making these foils a little easier to totally remove them from the bottle. (Thank God for tear strips, these types of foils are designed in two different segments a cap and a skirt, they are even made of nothing but plastic).
I agree with David, if you’re worried about metal foils (and possible the glue), totally remove the foil from the bottle and wipe the rim and neck clean.

Salute