Of the many customs, or minhagim, that we are privileged to enjoy on Pesach, the discussion surrounding the concept of kitniyos is especially fascinating. In truth, the custom itself is somewhat enigmatic, and its application and permutations could fill many volumes.
The basic laws of Pesach are that one may not eat nor own any chometz (leavened bread) and one must eat matzah (unleavened bread) on the first night. By definition, both chometz and matzah hail from the five major grains: wheat, rye, oats, barley and spelt. The sages teach us that these grains can become chometz when they ferment. The fermentation of all other foods, whether we call them a "grain" or not, is considered a sirchon – rot - and not chometz. Since matzah must be made from a material that has the ability to become chometz, the Shulchan Oruch (O.C. 453:1), a central Rabbinic text authored by Rabbi Yosef Kairo, establishes the rule that matzah may only be made out of the five grains and "not out of rice and other types of kitniyos, and these will also not become chometz." The word "kitniyos" is generally translated as "legumes" or "beans" but, alas, the use of a name is less than an exact science, as we can see from the language of Rabbi Yosef Kairo, where he combines "rice and other types of kitniyos" under one heading. In the context of Pesach, the definition of a legume has thus sprouted to encompass many more species and a good deal of controversy.
The real concern with kitniyos on Pesach is not based upon their inability to make matzah, but rather on a custom discussed by some Rishonim, the leading rabbis in the 11th-15th centuries, regarding avoiding their use entirely on Pesach. While it would seem fine to eat foods that cannot conceivably become chometz, these authorities were concerned that kitniyos might in some way become confused with true chometz. First, cooked porridge and other cooked dishes made from grain and kitniyos appear similar. Second, kitniyos are often grown in fields adjacent to those in which chometz is grown, and these grains tend to mix together. And third, kitniyos are often ground into a type of flour that can easily be confused with chometz. For these three reasons, the rabbis suggested that by avoiding kitniyos people would be better able to avoid chometz. The Vilna Gaon (Hagaos HaGra, ibid.) cites a novel source for this custom. The Gemara notes that Rava objected to the workers of the Raish Gelusa (the Exilarch) cooking a food called chasisi on Pesach, since it was wont to be confused with chometz (Pesachim 40b). The Tosefos commentary (ibid.) explains that, according to the Orech, chasisi are lentils and thus, argues the Vilna Gaon, establishes the basis for the concern of kitniyos.
Based on these considerations, the custom of the European Jews (Ashkenazim), codified by the Ramah (ibid), was to avoid eating kitniyos. The Jews of Spain and the Middle East (Sefardim), however, follow the opinion of Rabbi Yosef Kairo, and never accepted this custom. (Many Sefardim from Morocco and Northern Africa, however, follow Ashkenazic customs regarding kitniyos.) To this day, most Sefardim partake of rice, beans, maize, and other forms of kitniyos without compunction. It is critical to note, however, that while kitniyos on Pesach may be an exclusively Ashkenazic concern, actual chometz added to kitniyos is not. For example, vitamins are often added to rice, some of which pose serious chometz concerns. Even "corn" (glucose) syrup may contain enzymes that come from organisms that are grown on chometz ingredients and glucose syrup from some parts of the world is made from wheat starch. Clearly, any kitniyos eaten on Pesach is subject to standard Pesach concerns of chometz.
It is very important to recognize, however, that even according to the Ashkenazim, kitniyos itself is definitely not chometz. The Ramah himself notes this distinction in several ways. One is allowed to own and derive benefit from kitniyos, something that is prohibited with true chometz. The Mishnah Berurah (ibid, 7) commentary also notes that one who is ill may eat kitniyos even if his illness is not life threatening, and therefore most medicines that contain only kitniyos may be used on Pesach. One may also keep kitniyos in his house on Pesach without concern that it may be inadvertently eaten, and one may use it for any purpose except eating. Furthermore, if kitniyos becomes inadvertently mixed into a food, even on Pesach itself, it is considered nullified in the other food, and may be eaten.
Although virtually all authorities accept this approach to kitniyos as the normative Rabbinic basis for the custom, some authorities ascribe a more significant source to it. The Chok Yaakov (ibid., s.k. 4) quotes a Hasagos Ha'Ra'avad – the work of a 12th century Rabbinic commentator – in the first chapter of Hilchos Chometz U'Matzah to the effect that although the Rambam rules that the "material" may not be true chometz, it may nevertheless become chometz noksheh – "hard" chometz, which is still considered a negative prohibition. Most editions of the Yad Hachazaka indicate the Ra'avad's remarks as referring to the Rambam in Halacha 2, where he rules that flour mixed with fruit juice will never become chometz, and the Ra'avad comments that it may nevertheless become "hard" chometz (chometz noksheh). The Chok Yaakov, however, notes that in some editions, this Ra'avad is actually referring to the first law of the Rambam, where the Rambam writes that rice and other kitniyos can never become chometz. Were the Ra'avad to be referring to this part of the Rambam, he would seem to be indicating that kitniyos may be indeed pose a concern of chometz noksheh and be prohibited by the Torah! (One may bring a slight proof to this position, based upon Tosefos Pesachim 40b noted above, where they seem to say that kitniyos tend not to become chometz "as much" as true chometz. See Ma'Harsha, however, who dismisses this proof.) In any event, although he makes this observation, the Chok Yaakov himself seems to accept the position of virtually all other authorities and bases the concerns of kitniyos upon other factors.
As we have noted above, however, the criteria for determining what is – and what is not – kitniyos is less clear than the actual custom. Rice and beans are certainly included. However, Rabbinic authorities discuss several types of seeds (e.g. "anise" and "kimmel") that it seems were prone to being contaminated with kernels of wheat, and for this reason their use was prohibited. Contemporary authorities question the exact translation of these items, and for that reason many have the custom to avoid seeds such as caraway, cumin, or fennel that are similar to anise and kimmel. Similarly, authorities insist that coriander be carefully cleaned, since it is common to find grains of wheat or oats mixed into this spice. Mustard, according to the Ramah (O.C. 464:1), should also not be eaten on Pesach. The reason for this custom is a bit more obscure, but the Taz (453:1) explains that mustard is similar to beans in that they both grow in pods.
In the late 15th century, the cornucopia of foods from the New World brought items – such as maize and potatoes – to the fore. Both quickly became staples in the Old World, and although clearly not technically legumes, the question arose as to whether they should nevertheless be included in the category of kitniyos. Maize is generally considered to be kitniyos, whereas potatoes are not. Interestingly, the etymology of the names of these foods may give us some insight into this dichotomy. While the common name for maize (from the Tahino word "mahis") is "corn" – and in the United States this usage is quite clear – the origin of the word "corn" is quite different. The word "corn" can be traced back to the ancient Indo-European word "grn," which literally meant a small nugget. In German, this word became "korn" and in Latin, "grain," both of which include any edible grass seed. In practice, these terms refer to the predominant grain in a given country. In the Americas, it refers to maize, in Scotland to oats, and in Germany to wheat or rye. Indeed, old English translations of Pharaoh's insomniac premonitions refer to "seven sheaves of corn," which was really one of the five grains. Yiddish speakers are similarly prone to this confusion, since they often use the term "korn" to refer to grain. It seems, however, that the popularity of corn – and its resulting assumption of this sobriquet – was sufficient for the custom of kitniyos to extend to this new "grain."
Potatoes, on the other hand, were never considered grain, and therefore generally considered to have escaped the kitniyos categorization. (It is interesting to note that the Chayei Adam was of the opinion that potatoes should indeed be considered kitniyos. Much to our relief, however, this opinion was definitely not accepted.) Note: Rabbi Pinchas Epstein of Eida Hachareidis in Yerushalyim, who is of Lithuanian descent, considered potatoes kitniyos and the Eida did not approve it. When the Minchas Yitzchok, Rabbi Weiss, assumed the position of Gavad he accepted potatoes.
Many plants, such as soy, peanut, and corn, are processed into oil, and there is much discussion amongst the poskim as to whether the custom of kitniyos extends to oil produced from these plants. For this reason, many who do not eat peanuts on Pesach will nevertheless use peanut oil, since there is an additional reason to be lenient. Some authorities are also of the opinion that rapeseed oil (also known as Canola oil) can similarly be permitted, since rapeseeds are far removed from conventional kitniyos in that they are not eaten and were not generally available in previous generations. On the other hand, others contend that since rapeseed is a member of the mustard family, it should be subject to the custom cited earlier concerning mustard. In addition, it has been determined that rapeseeds are commonly contaminated with wheat kernels, thus meeting one of the classic definitions of kitniyos. The Alter Rebbe, Rabbi Schneur Zalman of Liadi, specifically forbids oils derived from kitniyos.
Some authorities carry concerns of kitniyos oil to an even more stringent conclusion. The generally accepted custom in the United States (based upon a ruling of the Tzelemer Rav) is to permit the use of cottonseed oil. In addition to the general leniencies relating to oil, cottonseeds are not even edible and thus arguably not subject to being considered kitniyos in the first place. However, the Minchas Yitzchok (III:138) and others bring proof that neither of these arguments is correct, and for this reason many people have the custom to avoid using cottonseed oil and content themselves with olive, walnut or palm oil. (It should be noted that the custom of the Minchas Yitzchok, which is followed by his followers and the B'datz Eida Hacharedis of Jerusalem, is to prohibit cottonseed oil. However, the Minchas Yitzchok himself, in a subsequent responsa (IV: 114), seems to be less sanguine on the matter. He quotes the opinion of Rav Meir Arik in the Minchas Pitim (Introduction of O.C. 453) that would seem to permit this product, and therefore questions his original prohibition.)
Sunflowers are a common source of oil in Eastern European countries, and some authorities consider this species to be the type of kitniyos referred to as "shumshmin" (see Marcheshes I:3, who makes the linguistic comparison between the name "sunflower" and the Hebrew word for the sun – "shemesh" – which he assumes to be the source of the name "shumshmin"). Other authorities, however, question this linguistic relationship (the correct pronunciation is "sumsimin", which is unrelated to the word "shemesh"), and permit the use of sunflower oil on Pesach.
Another common use of kitniyos is in the manufacture of glucose from cornstarch (corn syrup). Although we noted that some allow the use of oil from kitniyos, most authorities agree that corn syrup has the same Rabbinic status as the kitniyos cornstarch itself rather than that of the oil expressed from it. Corn syrup, and its specialized high fructose version, has long replaced sugar as the sweetener of choice for use in soda, which would pose a significant problem of kitniyos on Pesach. Fortunately, this is the "Pesach generation," and the major soft drink manufacturers make special productions of the world's favorite beverages for Pesach the old fashioned way – they use liquid sugar. (Some soft drink aficionados seek out the Pesach version of the "Real Thing", since it follows the original formula by using sugar instead of corn syrup!)
One final point concerning the application of the rules of kitniyos should be noted. Corn syrup and its derivatives are often used as the starting point for making other food chemicals. Citric acid is used as a flavoring agent in candies, jams, and many other foods. Erythrobic acid is used to maintain the red color in pickled and cured meats, and xanthan gum (xanthan gum from Europe is chometz) is used as a thickener. Aspartame is used as an artificial sweetener, and enzymes are used to make fruit juice and cheese. All of these products are routinely produced through fermentation and corn glucose, and their Pesach status has been the subject of much Rabbinic discussion. Rav Moshe Feinstein OBM indeed ruled that the custom of kitniyos never extended to such distant relations of cornstarch, and thus permitted citric acid produced through the fermentation of corn glucose. Some kosher agencies rely on this approach to permit one or more of the above products, and it is the responsibility of the consumer to verify the standards of the certifying agency with regards to these issues when purchasing products for Pesach.
As we have seen, issues relating to kitniyos have burgeoned over the centuries. Foods unknown when the concept of kitniyos was instituted have now become staples, and modern food science has found a myriad of ways to incorporate them into our foods in unforeseen ways. The Rabbinic underpinnings of such kitniyos issues are indeed fascinating, and serve as interesting grist for the Pesach mill.
The status of different types of beans is not quite clear. The general custom is to consider soybeans kitniyos, and we therefore do not use soybean oil for Pesach.
Peanuts, on the other hand, are a source of controversy that goes to the heart of kitniyos itself. Rabbi Moshe Feinstein OBM (Igros Moshe, O.C. III: 63) is of the opinion that peanuts are not kitniyos. He reasons that kitniyos is not a law but a custom. While customs often have the force of laws, Rabbi Moshe argues that the custom cannot be extended beyond what was actually included in the custom. Since peanuts were not in common use in Europe when the custom of kitniyos was instituted, there is no halachic basis to extend it to new items, even if they are arguably identical to other kitniyos in form and use. Indeed, there are communities that have a custom to eat peanuts (and "Kosher for Pesach" peanut butter!) on Pesach. While this may not be the generally accepted approach of most people, there are certainly ample grounds on which to rely in this regard.
Some contemporary authorities even carry this logic one step further. A type of grain, from the Andes Mountains, called "quinoa" has recently become popular and had certainly never been considered kitniyos because Jews before had never used it! Following the idea that new types of kitniyos cannot be created, these authorities permit all manner of baked goods to be made out of this exotic cereal. Others are less sanguine to this point, however, and reason that since quinoa exhibits properties classic to kitniyos, it should be so considered (as is the case with maize). Others have also pointed out that quinoa may nevertheless pose a concern because it is often processed on equipment that is also used for wheat and other grains. A competent Rabbinic authority should therefore be consulted before using quinoa.