I have read the Straight Dope classic
http://www.straightdope.com/classics/a971219.html
and now I am wondering how much aluminum
my aluminum rice cooker puts into my rice. I am
hoping that since rice and water is not very acidic,
that the amount of aluminum in the cooked rice
contributed by the rice cooker will be very small.
Can anyone give me some estimates on how much aluminum
the rice cooker is likely to contribute?
Got some stuff off Google for you, Curious. It ain’t good news.
First up, the stainless steel pot lobby: http://www.conterra.com/ehp/whyuse.htm
Next, the anti-aluminium guys: http://www.mercola.com/1998/may/25/aluminum_and_alzheimer_prevention.htm
And thirdly, these guys: http://www.gsdhelpline.freeserve.co.uk/toxin.htm
Dunno 'bout you, but I’m real glad milk containers down here in hometown ain’t lined with that stuff!
I’m not real sure on the aluminum controversy in health because as fast as someone points out any indications that the metal causes problems in the body, the aluminum people come out with reams of figures claiming that it’s all bunk. Knowing the history of American businesses to deliberately deny dangerous health effects of products to continue to make profits and avoid lawsuits, I am suspicious.
I have cleaned well used aluminum cookware, ones where the polish has worn off of the interior, and had paper towels come up silvery gray. I even took old club aluminum pots that did this and resurfaced the inside with a high speed (28,000 rpm) modelers tool (Dremel) with a fine wire brush. After washing, the paper towels used to dry the pots turned silver gray.
I’ve found pits eaten into the cooking surface of aluminum pots both of the cheap and expensive types. Since they started cheapening Teflon coatings, I’ve avoided Teflon coated aluminum pots because the Teflon comes off quickly and the aluminum is exposed.
Aluminum pots got my attention when I was using some cheap, thin pots and lived in a place with heavy iron well water. Any of these pots left with water in them started to dissolve! Really! I heard faint popping one quiet night and investigated to find little bubbles coming off of the bottom of the pots out of tiny pits eaten into metal! Even adding a water filter did not help much.
Then I read up on the suspected health effects of too much aluminum, found that most water treatment plants use powdered aluminum to settle out particulate matter in drinking water, alum used for pucker power in pickled goods is powdered aluminum, aluminum powder is used in silver paints, explosives and aluminum is used in hoards of wrappers for foods.
I got concerned and now I cook in stainless steel, copper or Pyrex.
They never used to consider lead dangerous either, and used it in house pipes, solder, canned good seals, paints, building materials, ceramic glazes used on tableware and in making pewter. Look what happened there.
My rule of thumb is, if you dry your aluminum cookware off with a paper towel and when wiping the cooking surface down, the paper turns grayish – then you’re eating too much aluminum. The amount of aluminum in your food should be in amounts far too small to show up on a paper towel.
Like chefs like to use copper pots because the copper lightly flavors the food, but none shows up on paper towels when cleaned later.
Find a steel rice steamer in a better store. Any place which sells high quality chefs materials will have them, though some of my friends swear by their bamboo steamers.
Alum is a class of compounds; there are many different types of alum. Pickling alum is is Potassium Aluminum Sulfate.
Some chefs like copper pots. This is because of the specific heat of copper. Copper heats more slowly than other metals thus distributes heat more evenly. This gives a pan without hot-spots.
Holden MacRoyne:
The functional ingredient is aluminum in all forms of alum, thusly the name ‘Alum,’ short for aluminum.
Cripes! Nitpick a little why don’t you?
first point: Yes, Aluminum is one of the elements in alum compounds. This, of itself, does not make it “available” to wreak havok on people who eat alum. Behold table salt. It is “made” of sodium and chlorine. If we ingested sodium, it would react with the water in our stomachs (assuming it got there) with bad results. Further, chlorine is highly poisonous. However, together, they are somewhat benign. Yea, without sodium chloride we would certainly die. The point? Just because alum compounds contain aluminum, they aren’t dangerous for consumption.
second point: I don’t feel that it was a particular nitpick. You stated that chefs liked copper because the copper lightly flavors the food and because the copper doesn’t wipe out of the pan. Neither of these is true. Copper cookware does not flavor food, at least not perceptably. To add a “metallic” flavor to food, I would imagine that the food must contain amounts of very strong Nitric Acid to react with the copper. Either that or one would have to cook at some incredibly high heat. (well over 300 C)
Aluminum has a very strong affinity for oxygen. As soon as aluminum is exposed to air, it forms aluminum oxide. This thin layer of oxide on all exposed surfaces of aluminum is extremely strong, chemically speaking; it is difficult to reduce aluminum ions in aluminum oxide to metallic aluminum. [sub]This leads to a very interesting story regarding Charles Hall, developer of the Hall process. While I won’t go into it here, I recommend that all interested readers do a google search on Charles Hall and the Hall process.[/sub] The result of this is that simply cooking on an aluminum surface is not a great way to get aluminum in the body. Of course, if you scramble your eggs in an aluminum skillet with a metal fork, you are likely to scratch up some aluminum. Then, ingestion is easier.
Just to add to the copper thing…
Usually people would not cook on copper. It’s toxic, for one, but usually not in the low doses you’d get from just cooking on it. Secondly, you have to keep it clean all the time - otherwise the green deposits that build up are toxic and unsafe. Also, it may discolor food. Copper’s an excellent conductor of heat, but all copper cookware should be lined with a different metal (usually stainless steel or tin).
I must disagree!
Alum is a definite byproduct of aluminum, as has been mentioned in anti-aluminum sites, though it doesn’t have that much.
Salt - sodium chloride is an organic compound, much like monosodiumglutomate. The combination of the two elements create a needed mineral for the body. Aluminum is not a needed mineral/chemical.
Copper cookware.
Having enjoyed cooking for quite some time, I will state that you may buy pure copper cooking utensils in most fine cookware stores. They are expensive! French Chefs have known for years that cooking in copper adds a subtle flavor to the food. Certain preparations are often simmered in copper to get that very subtle flavor, usually those containing acid.
Copper is hard to cook in because of the good heat conductivity but if you have ever seen pictures of a gourmand kitchen with professional chefs, you will find several battered, well used pure copper cooking pots hanging up.
Like cast iron. It’s a pain to use, being heavy, but is used for several reasons: the seasoning needed to cure the pan adds subtle flavors to the food, it distributes high heat well, and it adds a very faint iron flavor to the food, plus a touch of organic iron. Every chef has a few cast iron pots and pans.
Since I do a large amount of cooking, plus own high quality cooking pans, I might have a pretty good knowledge of this. I use stainless steel, copper bottomed pans – being unable to afford pure copper, pans with a distribution pad on the bottom, Pyrex, glass and cast iron. I don’t use aluminum.
That’s like I never buy and use an unglazed pottery oven cooker, nor will I buy one from just any store because you need to know what has soaked into the pottery prior to using it. I like to know what I cook in and what it does to the food.
Those new flexible high temperature plastic molds you see on TV have me suspicious. Most plastics when heated, even in a microwave, out-gas small amounts of vapors, which can change the flavor of the food. Like plastic bottles have affected the flavor of Coca-cola. I never use a microwave to cook in and never place food in it in anything but a glass container to defrost.
In short, I like to know what cooking containers do.
EEEEEEK! There’s aluminum in my toothpaste. Of course it is in the form of aluminum oxide (Al2O3, as an abrasive)and I couldn’t get the aluminum off of it with a torch or a hammer. The point being…STOP with the panic! Do you people believe everything you read? Metallic aluminum may well be bad for you, but how are you going to get it? Look at the periodic chart…do your valences and see what’s going to react with what. The poor guy who’s wiping off his aluminum pan is scraping off the oxide coating, allowing another to form in its place. He’ll get 10x the alumina if he swallows a little tooth paste. Relax folks…go bite a fork.
OK, roughly in order: First, while metallic aluminum might be bad for you, aluminum compounds most certainly are not. Al is the third most abundant element in the Earth’s crust, which means that for the past, oh, four billion years or so, life has had to deal with significant amounts of aluminum compounds. Due to the reactivity of aluminum, its compounds tend to be very chemically stable, so you’re not likely to get any elemental aluminum inside you from ingesting the compounds.
Secondly: Alum does, in fact, contain aluminum, but the word “alum” is not short for “aluminum”. Quite the opposite, in fact: Aluminum is long for alum.
Third: While aluminum may or may not be bad for you, most people could certainly use (or at least not be harmed by) a bit more dietary iron, and cooking regularly in cast-iron pots and pans is a good way to supply it.
Fourth: Copper is a noble metal. No acid you might ever conceivably find in any ingestable substance is going to eat away at it at all.
Fifth: Look up the definition of “gourmand”, SpyderA48. You may be surprised. The word you’re looking for is “gourmet”.
Thanks, Chrony, I thought I recognized you from my Inorganic Chemistry course! 
Sorry. Gourmet is what I meant. Damn spell checker!
I bow to your greater knowledge, but still will not use aluminum cooking gear, especially after discovering the pitting.
Ok, a couple of questions: were the posited, posted pitted pots (forgive me) shiny aluminum, or anodized (dull charcoal colored) aluminum?
I’m betting the former. Anodized aluminum, such as in the heavy, original Calphalon pots, generally doesn’t pit - it stains something awful, yes, but pitting? Never seen it.
The next question:
Do you cook with a lot of acid? Lots of tomato sauce, lemon juice, vinegar? Those will pit shiny aluminum (and they’ll eat right through aluminum foil).
Teflon coatings differ widely in quality. Check out Consumer Reports - in the February issue they did a follow-up report on nonstick frypans, and with ratings as to which nonstick surfaces were more durable. I’m not a great fan of non-sticks myself, since when food doesn’t stick it doesn’t give nice, burnt carmelized flavors for deglazing. But the article notes that there are some very good non-sticks out there - they just aren’t cheap (the highest-rated 12" skillets were both $115).
Copper is not toxic.
From “Domestic Water Treatment,” by Lehr (1980):
NaCl is decidedly not an organic compound. It is inorganic.
I disagree with the “at all” part. You have to consider equilbrium. Water that simply passes through copper pipes will have copper in it. (I’ve measured concentrations of more than 8 ppm coming out of a drinking fountain with copper tubing.)
Followup about copper…
The federal Secondary Drinking Water Regulation (U.S.) for copper in drinking water is 1.0 mg/L (ppm), based on taste and odor considerations. This is a non-enforceable guideline.
However, there is a Primary Drinking Water Regulation for copper of 1.3 mg/L, based on the possibility of gastrointestinal distress from short term exposure, and liver or kidney damage from long term exposure. So while copper is an essential mineral, excessive concentrations are not entirely innocuous.
Ever put a penny in a glass of vinegar (acetic acid)? Lots of foods contain this ingredient…
IIRC, the acetic acid eats away at the copper oxide and the zinc, not the copper itself.
::Looking at list of Standard Reduction Potentials and Activity Series::
Yep, copper is below Hydrogen. This means that copper as a metal will not replace hydorgen in a compound. Since the strongest acid in water is always hydronium (H[sub]3[/sub]0[sup]+[/sup] - old chemistry “trick” question") Arrhenious acids will not react with copper. However, there are compounds which will cause copper to oxidize. These could only be Bronsted-Lowry acids. (They, however, would not contain hydrogen as the positive ion. In fact, they are more likely to be covalent than ionic.)
On a list of Standard Reduction Potentials at 25 deg C, copper is above hydrogen. (The reduction of cupric ion to form solid copper is +0.34 V; the reduction of hydrogen ion to form hydrogen gas is defined to be 0.00 V.)
This means that hydrogen gas is a better reducing agent than copper metal. Alternatively, hydrogen gas is more easily oxidized than copper metal.
Copper will thus not react with hydrogen ion (or hydronium ion, if you prefer).
This is described by stating that copper will not react with nonoxidizing acids (an acid in which the anion is a weaker oxidizing agent than H[sup]+[/sup] ion).
Copper will react with some oxidizing acids, such as nitric acid. (An oxidizing acid contains an anion that is a stronger oxidizing agent than H[sup]+[/sup].)
Nitric acid is an Arrhenius acid (as well as being a Bronsted-Lowry acid), and it does of course have hydrogen ion as the positive ion. The reason it reacts with copper is because it is an oxidizing acid, and the nitrate ion is involved in the reaction (which is somewhat complex).
Where does the copper in the copper oxide go? Is it redeposited on the metal surface, or is it removed into solution/suspension?