# Tomato sauce eats aluminum foil **URL:** \ **Category:** Factual Questions\ **Created:** [August 7, 2008, 2:04am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112 "2008-08-07T02:04:34Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![billiscool](https://avatars.discourse-cdn.com/v4/letter/b/ad7895/32.png) [@billiscool](https://boards.straightdope.com/u/billiscool)\ **Post date:** [August 7, 2008, 2:04am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/1 "2008-08-07T02:04:34Z")
More than once I have noticed when aluminum foil is used to cover spaghetti or lasagna it was eaten away by the sauce. Has anyone else seen it? More importantly what is the chemical reaction? ---
**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\ **Post date:** [August 7, 2008, 2:10am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/2 "2008-08-07T02:10:18Z")
I have never noticed that but years ago I noticed that if you cook anything with tomatoes in an aluminium pan it leaves the pan spotlessly clean after washing. Since I stopped using aluminium pans long ago I forgot about it. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 7, 2008, 2:20am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/3 "2008-08-07T02:20:26Z")
Before I started using those plastic containers with lids I used foil to cover foods I was saving. I noticed that tomato sauce makes tiny holes in the foil. I put it down to acidity. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [August 7, 2008, 2:28am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/4 "2008-08-07T02:28:12Z")
[The Master speaks.](http://www.straightdope.com/classics/a1_121a.html) ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 7, 2008, 2:29am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/5 "2008-08-07T02:29:17Z")
Acid reacts with aluminum. 6H[sub]3[/sub]O[sup]+[/sup] + 2Al --\> 2Al(OH)[sub]3[/sub] + 3H[sub]2[/sub] I think that is balanced right. Aluminum hydroxide can lose water and precipitate out as Al[sub]2[/sub]O[sub]3[/sub]. In acid it will actually be protonated so you will have waters and a cationic aluminum complex. ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [August 7, 2008, 4:51am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/6 "2008-08-07T04:51:04Z")
[QUOTE=cecil] Ketchup is by no means the most potent product in your pantry in this respect. I note on my list of food acid levels that Coca-Cola, the all-American beverage, has a pH of 2.7. I guess if you spill a Coke aboard one of those aluminum naval vessels so popular these days, you’d better hope you can swim. [/QUOTE] But what about aluminum coke cans? How does that work? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 7, 2008, 5:57am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/7 "2008-08-07T05:57:39Z")
Aluminum will actually react on contact with water, not just cola. The trick, though, is that the surface of the aluminum very quickly forms a very thin layer of aluminum oxide, which doesn’t react with most common substances, and which (ordinarily, at least) protects the underlying metal from further corrosion. I’ve heard that the problem with aluminum and lasagna only occurs if there’s some other metal present, to form a battery like with Cecil’s braces-and-foil example. If the pan is also aluminum, or something nonmetal like glass, then the foil won’t be eaten away. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 7, 2008, 6:14am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/8 "2008-08-07T06:14:24Z")
Apparently, the cans themselves are coated with a plastic. [The Master Speaks again](http://www.straightdope.com/classics/a5_222a.html) Imagine, that was the first article I got from my google search. ---
**Author:** ![Carson\_O\_Genic](https://avatars.discourse-cdn.com/v4/letter/c/cdc98d/32.png) [@Carson\_O\_Genic](https://boards.straightdope.com/u/Carson_O_Genic)\ **Post date:** [August 7, 2008, 10:39am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/9 "2008-08-07T10:39:19Z")
My wife made a moist cranberry containing cake and covered it after cooling with foil. Next day the berries resembled chrome ball bearings. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [August 7, 2008, 11:25am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/10 "2008-08-07T11:25:57Z")
The acidic reaction with metal is why you don’t use aluminum or copper pans in canning or to store acidic food. In canning you are specifed to use non reactive pans so you don’t poison people with metal. I’ve also seen cans of food that warn to remove the food from the metal can after opening, to store the remainder. Be sure that you don’t put something like lemonade in the old [galvanized water coolers.](http://cgi.ebay.com/Sporting-Goods-vintage-galvanized-IGLOO-water-cooler-LG_W0QQitemZ300240715523QQcmdZViewItem?IMSfp=TL0807101223r39022) ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [August 7, 2008, 11:35am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/11 "2008-08-07T11:35:12Z")
[QUOTE=WarmNPrickly] Acid reacts with aluminum. 6H[sub]3[/sub]O[sup]+[/sup] + 2Al –\> 2Al(OH)[sub]3[/sub] + 3H[sub]2[/sub] I think that is balanced right. [/QUOTE] [nitpick]Looks like it should be 6H[sub]2[/sub] on the RHS.[/nitpick] ---
**Author:** ![billiscool](https://avatars.discourse-cdn.com/v4/letter/b/ad7895/32.png) [@billiscool](https://boards.straightdope.com/u/billiscool)\ **Post date:** [August 8, 2008, 2:53am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/12 "2008-08-08T02:53:14Z")
[QUOTE=Chronos] I’ve heard that the problem with aluminum and lasagna only occurs if there’s some other metal present, to form a battery like with Cecil’s braces-and-foil example. If the pan is also aluminum, or something nonmetal like glass, then the foil won’t be eaten away. [/QUOTE] The pan I see this occuring in is also aluminum but of a slightly thicker gauge. ---
**Author:** ![billiscool](https://avatars.discourse-cdn.com/v4/letter/b/ad7895/32.png) [@billiscool](https://boards.straightdope.com/u/billiscool)\ **Post date:** [August 8, 2008, 3:00am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/13 "2008-08-08T03:00:30Z")
[QUOTE=WarmNPrickly] you will have waters and a cationic aluminum complex. [/QUOTE] So is it poisonous? Will it migrate through the food like mold on cheese? ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 8, 2008, 3:29am UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/14 "2008-08-08T03:29:05Z")
Not likely, but I’ll shy away from saying that a metal is totally nonhazardous. There used to be some speculation about its relationship to alzhiemers but this has pretty much been discounted. > [@Dead Cat](#): > > [nitpick]Looks like it should be 6H2 on the RHS.[/nitpick] Doh! I knew I was going to mess that up on the fly so I left a disclaimer. ---
**Author:** ![BJMoose](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@BJMoose](https://boards.straightdope.com/u/BJMoose)\ **Post date:** [August 8, 2008, 5:27pm UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/15 "2008-08-08T17:27:43Z")
Many years ago I made the mistake of getting lazy and putting an aluminum pot with leftover chili in the reefer. Never did _that_ again. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 8, 2008, 5:30pm UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/16 "2008-08-08T17:30:53Z")
> [@](#): > > Many years ago I made the mistake of getting lazy and putting an aluminum pot with leftover chili in the reefer. I assume by reefer you mean refrigerator rather than the uh … more common usage. That’s new to me. ---
**Author:** ![MsFancyPlants](https://avatars.discourse-cdn.com/v4/letter/m/b487fb/32.png) [@MsFancyPlants](https://boards.straightdope.com/u/MsFancyPlants)\ **Post date:** [August 8, 2008, 5:34pm UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/17 "2008-08-08T17:34:17Z")
I’ve had good luck stopping the chemical reaction by covering my acidic dishes with the foil that has a silicon coating on one side. I think it’s called Reynolds Release or something like that. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 8, 2008, 5:50pm UTC](https://boards.straightdope.com/t/tomato-sauce-eats-aluminum-foil/459112/18 "2008-08-08T17:50:52Z")
Film at eleven!