Although quinoa is relatively new to the North American market, it has been considered a staple or “the mother grain” to the people of Peru and Bolivia for hundreds of years. To this day quinoa remains an important food in South American cuisine and is beginning to make headway as a lighter and healthier alternative to rice and couscous. Tiny and bead-shaped, quinoa cooks like rice and couscous. It is available packaged as a grain, ground into flour for bread-making, and in several forms of pasta.
Quinoa is a species of the goosefoot family (Chenopodium). As a “chenopod”, quinoa is closely related to species such as beets and spinach and is not considered to be a true cereal or grain. This is because quinoa stalks grow with broad leaves, unlike true grains and corn which do not. Although quinoa leaves are edible and can be eaten as a leaf vegetable, they are not available commercially because quinoa is generally harvested solely for its seeds.
On Pesach, it is forbidden to consume, derive benefit from; and even own chometz. Although actual chometz is limited to five species of grain, namely: wheat, barley, spelt, rye and oats, Ashkenazic custom forbids consumption of kitniyos. Kitniyos is loosely translated as “legumes” but it is actually much broader in application. A legume would be a “fruit” that grows inside a pod, such as beans and peas. Kitniyos, on the other hand, is a categorical term and includes grains and cereals such as rice, millet, corn, and some seeds such as mustard and poppy seeds. On a basic level, it can be argued that quinoa should not be classified as kitniyos because it is not a legume, grain, cereal or even a true seed, but rather it is a vegetable.
In order to consider this argument, we must explore the reasons behind the custom of prohibiting kitniyos on Pesach. The Poskim provide two primary reasons for its institution:
1. It is not uncommon to find chometz grains mixed together with some types of kitniyos in a manner that is difficult to recognize and sift properly.
2. Kitniyos and chometz can potentially share several common characteristics: 1) some kitniyos dishes are cooked in a manner that is similar to the way that chometz dishes are cooked; 2) some kitniyos are ground and made into flour which can then be used for bread-making; 3) some kitniyos can look similar to chometz grains; and 4) some are harvested and stored in a manner that is similar to grains. Because kitniyos and chometz share common characteristics, an allowance of kitniyos on Pesach could lead to confusion and perhaps eventually lead to leniency in regard to actual chometz.
In addition to the kitniyos species that were prohibited because of these two reasons, the category was expanded to include species that grow on sharvitin (stalks), similar to other legumes and kitniyos grains, even when the two aforementioned reasons do not directly apply. Primary examples of this type of kitniyos are mustard seed and rapeseed (canola).
Let us now examine quinoa in light of this information. Last year, Star-K Kosher Certification posted a “kashrus alert” stating the results of a recent investigation into quinoa production. Their investigation found that it is possible that quinoa grows or is processed in the proximity of chometz. Other organizations have stated that quinoa can be packaged together with chometz grains. As such, it appears to be possible that some packages of quinoa can contain chometz grains. Quinoa can be made into dishes that resemble chometz and quinoa flour can be used to make bread! Furthermore, quinoa is harvested for its seeds which are stored in silos, in the same manner as chometz grains and other kitniyos. Finally, quinoa grows on sharvitin, long stalks, similar to the way that other kitniyos grow. Accordingly, it would seem clear that quinoa ought to be considered kitniyos.
Before we can arrive at a conclusion, we must consider one additional factor. In a well-known teshuva, Rav Moshe Feinstein zt”l was asked about whether peanuts and peanut oil are considered kitniyos. Rav Feinstein stated that we cannot categorize a particular item as kitniyos strictly based on the aforementioned reasons. One need not look further than potato starch, a true staple of the Pesach Holiday, to realize that we cannot possibly consider all items that are made into “flour” as kitniyos. Rather, the custom of kitniyos must have developed differently than other customs and only foods which were clearly and specifically included in the custom are forbidden. When it comes to a “new” product, such as the potato, which was not in existence when this custom was formulated, the Rabbanim used their discretion to make an exception. In this vein, Rav Feinstein permits peanuts and peanut oil unless a specific custom exists to the contrary.
This reasoning could potentially be applied to quinoa such that we should not consider quinoa to be kitniyos because it is new to the Jewish world and there may be room for rabbinic discretion. Nevertheless, it must be stated that corn/maize was also introduced to the Jewish world after the custom had taken root and is considered kitniyos by all communities. Furthermore, it seems apparent that the vast majority of Ashkenazic communities do consider peanuts and peanut oil to be kitniyos! It would appear that the overwhelming consensus is not to allow discretion in regard to kitniyos and to subject every questionable item, even those introduced after the formulation of this custom, to the strict parameters stated above.
In light of these arguments, COR and many halachic authorities consider quinoa to be kitniyos. As there are differing opinions, it is important to consult with your Rav on this matter as well as on all matters of halacha and minhag.
1 One can find on the internet numerous gluten-free bread recipes that are made with quinoa flour.
2 See http://en.wikipedia.org/wiki/Quinoa and http://www.saltspringseeds.com/scoop/powerfood.htm for more relevant information.
3 Rama, Orach Chaim (OC) [453:1]
6 Mishna Berura, [ibid.:3,4]
7 Rama, OC [464:1]. See COR Passover Guide, page 9 for a list of produce that are categorized as kitniyos.
8 This category can be called “min yerek” which is permissible as per Shulchan Aruch HaRav [453:4].
9 Mishna Berura, [ibid.:6]
10 Aruch HaShulchan OC [453:4].
11 Mishna Berura [ibid.]
12 Shulchan Aruch HaRav OC [453:4].
13 Shu”t Terumas Hadeshen [1:113]. See also Chok Yaakov OC [ibid.:5] and Mishna Berura, OC [464:5]. “Midi d’midgan” includes grains and seeds that are stored for lengthy periods of time in silos.
14 A sharvit is literally translated as a wand or a scepter. This expanded definition serves to include anything that grows on a long stalk.
15 Taz OC [ibid.: 1] Mishna Berura [ibid.] states that mustard seed is kitniyos because it is midi d’midgan.
16 Shu”t Avnei Nezer 
19 Shu”t Igros Moshe OC [3:63]
20 See http://en.wikipedia.org/wiki/Potato for more information
21 See http://en.wikipedia.org/wiki/Maize for more information
22 Mishna Berura [453:4]
23 It must be stated that, even according to the lenient opinion or for Sephardim who do not have the custom of kitniyos, quinoa must be checked by someone who knows how to distinguish between grains to ascertain that it doesn’t contain any wheat or barley.