A few days ago, my son noticed that a small aluminum tin that we used had a stamp from the Badat"z that said Kosher L'Pesach.
I know that people put food in aluminum tins. But I don't know of anyone eating the tins. Why would it need this certification? Is there a general year-round kashrut problem or just a possible chametz problem?
The OU has a long article explaining the possible issues with aluminum foil and aluminum pans. Due to the concerns raised in the article there are those who manufacture aluminum in a way to avoid a possible issue.
My understanding is that on Pesach when people are more careful than usual, even those who rely on the leniencies during the year may be extra careful and use only a product that has a strict supervision in place.
During the manufacture of aluminum foil, molten aluminum alloys undergo a series of rolling processes between top and bottom rollers. During this process, release agents or lubricants are applied to production lines that the foil comes into direct contact with. However, initially the potential kashrus concerns are somewhat abated, since during production the foil undergoes a process known as annealing, which exposes the foil to a heat exceeding 1,000 degrees Fahrenheit. This process would certainly burn any non-kosher residue the aluminum foil might have come into contact with, and also qualify as a kashering through the process of libun chamur. However, toward the end of the process the temperature does drop somewhat considerably. Although any foreign residue present on the foil’s surface would still certainly be burnt out, the process would no longer achieve kashering temperatures of libun chamur, and ta’am (taste) from lubricant at that stage would be absorbed by the foil. However, since the presence of release agents is always very minimal, any ta’am that the foil could possibly impart would always meet bitul proportions and become nullified in food. In halacha, this is known as a keili hassui lehishtamesh beshefah, which is a utensil that absorbed non-kosher taste in such minimal amounts, that the ta’am imparted by the utensil will always become botel in the food cooked. The Mechaber is lenient and allows one to use a keili hassui lehishtamesh beshefah without hesitation. However, the Taz disagrees and only permits the use of a keili hassui lehishtamesh beshefah if the issur and ta’am imparted is unpalatable. There is a debate amongst authorities if a utensil is permissible after a 24 hour period elapses, since once an eino ben yomo, the bliyos (taste absorbed by the utensil) would be no longer be palatable . This leniency would certainly apply to aluminum foil, which is never available for retail sale on the market until well after a 24 hour period has passed. Moreover, Rav Moshe Feinstein zt’l is quoted as being lenient with aluminum foil, with slightly different reasoning. According to Rav Moshe, since this particular type of kli (utensil) is never available for purchase until after a 24 hour period has elapsed, the gezeira mederabbanan should not apply altogether.
Aluminum pans are manufactured in a similar fashion to foil and the potential kashrus concerns are similar. However, there is one additional consideration with pans. During manufacturing, thick foil is stamped and formed into a pan shape and a very thin non-stick coating is applied. This thin coating is a possible point of concern as well. Therefore, some recommend washing the pans before use , although it is questionable whether this will effectively remove the coating from the pan and obviate this concern. Nevertheless, since the amount of any possible treifos present would be highly minimal, there is still basis to be lenient.
Although there is a possibility on some level that these questionable materials could contain non-kosher components, research appears to indicate that this issue is more likely to be just theoretical. Another very important piece of the puzzle is that very often a release agent or aid, even when containing a non-kosher component, is independently foul tasting and not fit for consumption. Although these materials will even come into direct contact with food, they are present in such minute amounts that they will not alter a product’s quality profile or taste. If the agent is foul tasting and independently inedible it should be permitted on the basis of being nifsal meachilah. Nevertheless, there is an opinion that if possible, these items should lechatchila be purchased with a proper hechsher.
Although the OU includes disposable baking tins and Star-K (pg 5: "All disposable foil products may be used") as things which don't require a hechsher for Pesach, it seems the OK would require a hechsher as they write,"Aluminum foil pans may be coated with a substance that is problematic for kashrus. Kosher consumers should purchase foil pans with a hechsher OR burn out the pan by inverting it over an open flame for approximately 20 seconds" for year-round use.
Personally, I've heard from various people in the kashrus industry - not any one particular hashgocha - where there's a demand, kashrus organizations will give a hechsher on products which don't necessarily require it. That certainly doesn't translate into the Badatz's hechsher as GershonGold quoted solid reasons. Nonetheless, at one of the kashrus sessions I attended a couple summers ago, they shared a real story of Fuji Film wanting a hechsher on their film...when asked why, the company said, "Our marketers tell us putting the kosher symbol on our product will boost revenue." If people will look only for kosher for Pesach tins, then you now have a money maker!
