Chametz in food is specifically defined as one of the five grains, wheat, barley, oats, rye or spelt that has been mixed with water and allowed to ferment. Empirically, it was observed as early as the rabbinic age that within about eighteen minutes (coincidentally, 18 in the Hebrew letter/numbering system is yod chet which, reversed, spells chai, life–a very special number indeed!) the heat from the chemical reaction which converts the starch creates heat and sufficient, although in fact minuscule, airflow to cause dough to rise. In the strictest sense, this is the narrow definition of chametz.
However, the original rabbinic definitions of chametz expanded the category to include any product derived from this fermentation process involving any of these grains, specifically beer and other grain-based spirits. Additionally, even unprocessed grains or products which contain them are also removed from the diet because they can easily become moist and thus spontaneously begin to ferment.
Ashkenazi tradition, the customs of Jews from the non-Mediterranean portions of Europe, also forbade legumes (peas, beans, lentils, etc.) as well as rice , all of which, since not actually chametz, remain allowed by most Sephardic authorities even today. The reasons given for this additional prohibition tend to fall into one of two categories, either that when ground these also appear to “puff” with water and thus resemble chametz all too closely or that in the open markets of those days the bins for legumes were often placed near the bins of actual chametz grains and so some chametz might fall in. In any event, until very recently even the strictest Ashkenazi customs would allow totzeret kitniyot, products derived from legumes (such as oils, peanut butter and the like). The current trend is to forbid them as well. I’m not sure of the reasoning behind this.
During the year, most mixtures which include a minuscule amount of a forbidden substance (usually less than 1/60th of the total) are permitted since the culprit is considered so insignificant as to essentially no longer exist. However, this reasoning is not followed for chametz during Pesach. Because of the fats, oils and other flavors than are absorbed into dishes, pots & pans, silverware and other utensils, even these minuscule amounts lead to either using separate Pesach dishes or kashering, i.e. purging all chametz from our regular dishes.
Rabbi Irving “Yitz” Greenberg, in his book The Jewish Way, suggests that this is because we want to draw a total distinction between slavery and freedom, that any hint of the “old ways” of slavery are no longer acceptable to any degree during this celebration of freedom. Another interpretation looks to the birth experience of Pesach (the escape from Egypt, Mitzrayim, literally the narrow place is often seen as a metaphor for the birth of the Jewish nation, having entered Egypt as merely a tribe of seventy souls). Just as a baby is able to eat only a very limited palette of food, as a Nation, while we’re still in our infancy (before reaching the eighth day (of the brit mila) for example) our ability to spiritually digest food (in other words, to engage the holiness within its physicality) is severely limited. Please note, this in no way suggests feeding Matzo to young babies!
When discussing chametz, it’s essential to keep in mind that the real chametz we want to eliminate is that within our personalities and actions. The physical foodstuffs are mainly a reminder, a pointer inside. The obvious metaphor is trying to refine out that which puffs us up unrealistically. A healthy ego is an integral part of being human and we certainly can’t journey to freedom without self-esteem. But we can try to pare down to the pure, unfermented essence of ourselves, to celebrate and enjoy ourselves and others without artifice. Another way of looking at chametz is that which has just stood around, beginning to stale, just as do so many of our unconscious habits which build up over a year.
For practical purposes (as if anything about ritual is, or is meant to be practical), the first step is to remove bread, crackers and other food containing these grains from our diet for the week. This can be extended to remove these foods entirely from our house. Since this can create a major hardship, the Rabbis long ago devised the mechanism of selling all chametz to a non-Jew during that week (since there’s no reason in a world why anyone not following Jewish tradition shouldn’t possess chametz). This is usually done through a rabbi in a way that the sale is authentic and absolute, but also so the chametz conveniently reverts to the owner immediately after Pesach. Because of the complexity of the food industry, one may try to eliminate, at least from your weekly diet, all processed foods which haven’t been made specifically kosher for Pesach, in other words, which might contain any chametz.
As mentioned earlier, the next step can be to either use special Pesach dishes or to kasher the ones we regularly use. The first step here is to clean everything thoroughly, refining the exterior. It’s a good idea to meditate on refining our own exteriors, our actions towards others, at this point. We then let them rest for twenty-four hours–we can’t expect to transform ourselves instantly. The next step is to remove the absorbed chametz. The physical principle is that we expel chametz the same way it was absorbed. (This is not unrelated to the technique of trying to re-envision those experiences which have hurt us and caused us to block our internal energy and work our way through them to greater clarity, joy and freedom. In other words, this is the inner work to accompany this process!) In other words, pots and pans that have been used for cooking on a flame can be kashered by filling them with water and bringing to a strong boil. Ovens and baking utensils should be brought to at least as high a temperature as used in baking and allowed to remain that hot at least until no further odor is smelled (in other words, the chametz has actually burned out). Dinnerware and silverware which have held hot food need only to have boiling water poured over them. Some people want to go farther and actually immerse them in a pot of boiling water. Anything else which is only used with cold foods generally never absorbed chametz to begin with so don’t need any further treatment. (I think there is a relationship to the degree of emotion (its heat) when we’ve been hurt and the effort needed to reprocess, transform and then refine it.)
Remember, distinguish between Pesach preparations and Spring Cleaning. Overdoing it to the point of resentment, exhaustion, shortness with children and the like obviously defeats the purpose. Enthusiasm is healthy, but obsession is not. Chametz is not magical and it can’t jump from surface to surface. And yes, while spiritually we do want to hunt even the chametz we can’t see, physically if you’ve already cleaned it you’ve done enough.
A fundamental principle throughout Jewish tradition is mentioned by King David in Psalm 34, Sur me-rah v’oseh tov, “turn away from evil and do good”. As we remove the chametz from our diet, we then introduce the simpler (at least in theory–there’s no accounting for the exponential growth of the Pesach food industry) Pesach food for the week. The first Pesach food, of course, is Matzo, and there are many brands and types available. Some people try to eat only shmura matzo, that is matzo which has been in constant supervision since the time the grain was harvested. It’s usually much more expensive than “regular” matzo. Some people want shmura matzo for the Seder but eat regular matzo the rest of the time. Some people enjoy egg-matzo and others consider it chametz. There is a wide range and it isn’t necessarily true that “the stricter the better”. If it distracts from the greater purpose, the journey towards freedom, take it easier. If it inspires you, by all means continue.
In general, all fresh fruits and vegetables (excluding legumes for those who follow the Ashkenazi custom) are fine. So are all fresh herbs or pure spices (although some Ashkenazi traditions also avoid ground seeds like mustard, turmeric, cardamom and the like because they tend to absorb water and thus appear to swell). Milk and uncolored butter, if bought before Pesach are certainly fine and many authorities accept that bought during the holiday as well. People who buy kosher cheese throughout the year will find that most is also Kosher for Pesach as well. Of course, processed food that’s marked Kosher for Pesach ought to be alright (although some products fall into Ashkenazi/Sephardi or other grey areas, but why make trouble where there isn’t any?). Almost all kosher wine is processed year-round Kosher for Pesach. Grain-based spirits, as well as flavors processed with alcohol (also as ingredients within processed food (and this is where one tends to rely on rabbinic supervision)–the complexity of the food industry again!) are also chametz. Although there really isn’t any difference between meat or fish for Pesach, many people who eat meat tend to make sure it’s marked Kosher for Pesach. Oils are another controversial subject, but all authorities agree that extra-virgin olive oil is always Kosher for Pesach, with our without supervision, regardless of brand. Currently there is a tendency to avoid oils which are derived from legumes (totzeret kitniyot) although many families traditionally used peanut oil on Pesach. Kosher for Pesach cotton-seed oil us currently very popular, but it is not only highly expensive, it really isn’t even food and there are some orthodox rabbis, even among the most traditional, who discourage this oil both for moral (price-gouging) and health reasons.
And turning to health, certainly any essential medicine is Kosher for Pesach. Many popular optional medications (Aspirin, Tylenol, anti-acids, decongestants, etc.) are also Kosher for Pesach even without kosher symbols. In questionable cases, often the best advice is that if you don’t need it, try getting along without for the week. Possibly not a bad start for the rest of the year!
Remember that the idea is to simplify, to refine, to return to our basic selves and to nurture ourselves to greater wisdom, maturity, awareness and compassion, all of which can also be called freedom. It’s not so much a matter of how religiously or how right one is as a matter of the ever-developing quality and quantity of involvement, year after year.
Chag Kasher V’Sameach, a Happy and Kosher Holiday since without Happiness there is no Kashrut.