The Laws of Pesach - Defining Chametz (1)
In memory of Yakov Yehuda ben Pinchas Wallach
and Miriam Wallach bat Tzvi Donner
Definition of Chametz
The Torah prohibits two forms of leaven, chametz and se’or, both of which are created by mixing flour and water. Chimutz (leavening) occurs when a mixture of flour and water is left alone and the fermentation process begins. While a mixture of flour and water alone will ferment and become chametz, yeast is often added to a mixture in order to hasten and increase the fermentation. Se’or, a yeast or sourdough mixture, is chametz that is left to become sour and inedible. It contains a concentrated mixture of yeast and bacteria that can be used to leaven bread. In short, while chametz is intended to be eaten, se’or is used for the preparation of leavened products.
The gemara (Pesachim 35a) teaches that just as one can only fulfill the mitzva of eating matza with matza made with one of the five grains, (wheat, spelt, barley, oats, or rye), only these grains, when mixed with water, can become chametz.
These are the ingredients with which a man discharges his obligation on Passover: wheat, barley, spelt, rye, and oats. Only these [are fit], but not rice or millet.
From where do we know this? Reish Lakish said, and thus the
When these five grains come into contact with water, they may potentially become chametz, even without the aid of a leavening agent such as yeast. Other substances, even those that can be used to create dough and bread, such as rice, beans, lentils and other legumes, cannot become chametz.
Two passages in the third chapter of Pesachim discuss the definition of “chimutz” (leavening). One passage (Pesachim 48b) presents the physical characteristics of chametz. The mishna describes the leavening process as follows: First, the dough becomes pale, similar to the appearance of a man whose hair stands on end out of fright. Next, cracks begin to develop on the dough’s surface, described by the mishna as “karnei chagavim” (locusts’ antennae). The cracks then begin to increase and merge into each other.
Chazal debate at which point the dough is considered to be sei’or, dough that has not fully leavened (not to be confused with se’or, sourdough). Although one may not eat such a mixture, it is not considered chametz. There is further discussion regarding when the dough actually becomes chametz, described by the mishna as “sidduk” (dough that displays cracks indicating that it has become chametz).
Sei’or must be burnt, but he who eats it is not culpable. Sidduk must be burnt, and he who eats it [on Pesach] is liable to karet.
What is sei'or? [When there are lines on the surface] like locusts’ antennae. Sidduk is when the cracks have intermingled with each other: this is the view of R. Yehuda. But the Sages maintain: Regarding both, one who eats [the mixture] incurs karet. And what is sei'or? When its surface has turned white, like [the face of] a man whose hair is standing on end [from fright].
R. Yehuda maintains that at the first stage, when the dough becomes pale, the dough is permitted mi-deoraita, and is considered to be matza. When dough reaches the second stage, it is called sei’or and must be destroyed, although one who eats it does not incur karet. Only when the dough develops cracks that have spread and intermingled is the mixture considered to be chametz.
The Sages disagree. They identify the first stage, when the dough is pale, as sei’or, which they claim is Biblically prohibited, although one does not incur karet for eating it. The second and third stages are considered to be full chametz, punishable by karet. The gemara (ibid. and 43a) attributes this position to R. Meir.
The Rishonim and the Shulchan Arukh (451:2) rule in accordance with the Sages (and R. Meir) regarding the definition of chimutz. It is forbidden and punishable by karet to eat the mixture once it has developed cracks like a “locust’s antennae.” The severity of the prohibition of eating sei’or will be discussed below.
The Rambam (Hilkhot Chametz U-Matza 5:13) writes that if the dough rose enough that if one were to hit the dough it would produce a sound (the sound produced when dough filled with air is struck), it is considered chametz even if it has not yet formed cracks. Furthermore, the Me’iri (Pesachim 45a) notes that if the dough rises completely, even if there are no visible cracks in the dough, it is still considered chametz.
Another passage in the gemara (Pesachim 48b) discusses whether dough which does not display the common external signs of leavening, described by the mishna as “deaf dough” (batzek ha-cheresh), is considered to be chametz.
[Regarding] “deaf” dough, if there is [a dough] similar to it which has become leaven, it is forbidden.
Even though this dough does not display signs of leavening, if dough which was kneaded at the same time became chametz, then this dough is also considered to be chametz. The gemara continues to discussing this “deaf” dough.
What if there is no [dough] similar to it? R. Abahu said in the name of R. Shimon ben Lakish: [The period for fermentation is] as long as it takes a man to walk from the Migdal Nunia [
If the mixture remains together for a period of a “mil,” that is, the time it takes to walk the distance of a mil (approximately a kilometer), then we consider the dough to be chametz even without external indications. This period is generally understood to be approximately 18 minutes long (Terumat Ha-Deshen 167; Shulchan Arukh 459:2).
The Rishonim dispute how to understand this mishna and they discuss the significance of and the relationship between the physical indications of leavening and the time period of 18 minutes.
Rashi (s.v. batzek) and the Me’iri (s.v. batzek) explain that this “deaf” dough has changed slightly in appearance, but has not developed the classic signs of leavening. “It is different - like a deaf person who has ears, but one cannot discern whether or not he hears” (Rashi). Rashi adds that some explain that the dough is “hard as a rock” (batzek ha-cheres), although it has not yet developed the cracks characteristic of leavening. In other words, had its appearance been normal, we would not have been concerned at all that it had leavened. However, since this dough looks different, although the classic signs of chametz have not developed, the gemara teaches that after the time of a “mil” has passed, the dough should be considered chametz.
According to Rashi and the Me’iri, time itself is not an indication of leavening; only when a doubt regarding the dough arises do we take the time that has elapsed into account.
Similarly, the Ra’avad claims that while dough that has leavened produces a very distinct sound when it is hit, “batzek ha-cheresh” produces a lower sound. This sound may be indicative of leavening, although we do not consider this dough to be chametz until dough kneaded at the same time has leavened or until the time of a mil has elapsed. The Ra’avad, like the Rashi and Me’iri, does not believe that time alone determines chimutz unless the dough itself shows ambiguous signs of leavening.
The Rambam (Commentary to the Mishna, Pesachim 3:2) disagrees. He explains:
“Batzek ha-cheresh” refers to a case in which one hits [the dough] with one’s hand and it does not produce an “echo sound,” as if it were deaf and does not respond after being called.
According the Rambam, this ordinary dough, which displays no physical signs of leavening, would still be considered chametz if dough kneaded at the same time has already leavened or if the time it takes to walk a mil has passed. Indeed, the Rambam (Hilkhot Chametz U-Matza 5:13) rules:
As long as one is actively kneading the dough, even for the entire day, the dough does not become chametz. If, however, he stopped working the dough and let it be, and it reached a stage at which it will produce a sound if one hit it, it has become chametz and should be burned immediately. If, however, it does not produce a sound, if it has been left for the time it takes to walk a mil, it has leavened and should be burnt immediately.
In other words, according to the Rambam, not only physical characteristics determine whether dough has become chametz. If a mil has elapsed, then the dough is considered to be chametz even without displaying any signs of leavening. The Ritva (Pesachim 46a) offers a different interpretation of “batzek ha-cheresh,” but he agrees that dough that has been left for the time it takes to walk a mil is considered chametz.
Until now, we discussed the physical characteristics of chametz and whether leaving dough for a period of time necessarily leads to chimutz. The Rishonim disagree regarding another aspect of the leavening process as well. The gemara (48b) teaches: “As long as they are engaged [in working] on the dough, it does not come to fermentation.” This passage implies that as long as the dough is kneaded or worked, chimutz cannot occur.
The Rambam, as cited above, rules that as long as one works the dough, even for an entire day, the dough does not become chametz, and, as some Rishonim understand his opinion (Ran, Ritva), one may even choose to knead the dough for longer than the time it takes to walk a mil. Rashba (Responsa 1:124) concurs.
The Ritva agrees that as long as the dough is worked, it does not become chametz. However, he states that one should preferably not work the dough for longer that the prescribed amount, the amount of time it takes to walk a mil.
Some Rishonim disagree. R. Yehoshua Boaz ben Shimon Baruch, (Shiltei Giborim; d. 1557), for example, in his comments published on the
Other Rishonim raise additional concerns related to the chimutz of this dough. The Rosh (Responsa 14:4), for example, writes that after the dough has already been worked, even if it is left for a short time, it may become chametz immediately. In addition, the Terumat Ha-Deshen (123) discusses whether interruptions in the kneading process combine to reach the shi’ur of a mil, at which point the dough would be prohibited. He concludes that if one thoroughly works the dough, the eighteen minute count begins anew with each interruption. Merely poking holes in the matzot, however, does not stall the process of chimutz.
R. Yosef Karo, in the Shulchan Arukh (459:2), concludes:
One should not leave dough without it being worked, even for a moment. As long as one is working the dough, even for the entire day, it does not become chametz. If one left the dough without working it for a mil, then it becomes chametz. The period of a mil is 18 minutes.
The Rema adds:
One should be stringent regarding the making of matzot, as one should be concerned that even brief interruptions [in working the dough] will combine to the time of a mil or that it will be in a warm place that hastens the leavening process.
The Shulchan Arukh continues:
After one is finished working the dough and it has warmed up in one’s hands, if one does not continue working the dough, it will become chametz immediately…
If it ferments until there are [visible] cracks, even if the cracks have not intersected, but rather one goes in one direction and another in a another direction, it is considered to be chametz and one who eats it incurs the punishment of karet. However, if there are no cracks, but the dough becomes whitish … one who eats it is exempt.
The Shulchan Arukh rules in accordance with R. Meir regarding the physical characteristics of chametz and in accordance with the position of the Rambam, who rules that even without the physical signs of leavening, dough which was left for more than 18 minutes is considered chametz. He similarly rules like the Rambam in permitting one to work the dough for the entire day, although the concerns of the Terumat Ha-Deshen and the Rosh are also recorded.
In numerous contexts, the gemara discusses substances that are not considered matzot, although technically they are not chametz either. The gemara calls these substances “chametz nuksheh.”
We find two example of chametz nuksheh in the Talmud, although the relationship between these two types, as we shall see, is subject to question.
As discussed above, the mishna teaches that sei’or is prohibited. The Tana’aim debate two separate questions regarding sei’or: its definition and level of prohibition. According to R. Meir, once the dough’s surface has become a pale white, it is rendered chametz nukshe. One who eats this dough violates a Biblical prohibition and receives malkot, but he does not incur the punishment of karet. R. Yehuda, however, believes that dough which becomes pale is prohibited only mi-derabbanan; dough which develops early signs of chimutz, such as cracks that appear like locusts’ antennae, is prohibited, although one does not receive malkot.
(The gemara (Chullin 23b) offers two understandings of why one is exempt from malkot for eating such dough: either there is a safek (doubt) whether it is truly chametz or not, and therefore one cannot be liable for eating it, or it is considered to be its own stage of leavening (birya) - it is not matza, but not yet chametz. The Acharonim discuss whether R. Yehuda believes that this dough is prohibited mi-deoraita or mi-derabbanan.)
Leaving aside the questions of definition and level of prohibition, the mishna strongly implies that chametz nuksheh refers to a mixture in which the process of chimutz was not completed.
On the other hand, the gemara elsewhere (Pesachim 43a) equates this dough with other inedible substances described by the mishna (42a) and referred to as chametz nuksheh. The mishna (42a) teaches:
The following [things] must be removed on Pesach: Babylonian kutach, Median beer, Idumean vinegar, Egyptian zithom, the dyer's broth, cook's dough, and the scribes’ paste. R. Eliezer said: Women's ornaments, too. This is the general rule: Whatever is of the species of grain must be removed on Pesach. These are subject to a warning [i.e., Biblically prohibited], but they do not incur karet.
This mishna discusses chametz mixtures (ta’arovet chametz), as well as chametz nuksheh. Regarding both categories, the mishna rules that they are Biblically prohibited. The last three examples of the mishna, the dyer's broth, cook's dough, and the scribes’ paste, are prohibited because they are chametz nuksheh. It would seem that these substances are placed in a separate category because they were never fit for human consumption.
What is the common denominator these two types of chametz nuksheh, the sei’or (in which chimutz is incomplete) and inedible chametz mixtures mentioned by the mishna (42a)?
Rashi (43a, s.v. sei’or) implies that sei'or is also prohibited because it is not fit for consumption. Therefore, according to Rashi, both types of chametz nuksheh are similar in that they are not edible. Others (see Minchat Barukh 44) suggest the opposite: both sei’or and the other substances have not completed the process of chimutz, and they are therefore unfit for human consumption. Most Rishonim, however, apparently understood that there are two types of chametz nuksheh: substances that have not completely leavened and those that are not fit for human consumption. Neither is considered to be chametz gamur.
What is the relationship between chametz nuksheh and chametz gamur (full chametz)? As noted above, R. Meir (and R. Eliezer in Pesachim 42a) believes that one who eats chametz nuksheh also violates a Biblical command and incurs malkot. Therefore, this question is even more significant according to R. Meir, who prohibits chametz nuksheh mi-deoraita.
Are we to view chametz nuksheh as a lower form of chametz that thus incurs a lesser punishment, or as a completely separate category? According to the first understanding, other laws of chametz should apply to chametz nuksheh as well, while according to the second understanding, there may not necessarily be any halakhic overlap between chametz nuksheh and chametz gamur.
The Rishonim debate whether, according to R. Meier, the prohibition of bal yera'eh (the prohibition to see/own chametz) applies to chametz nuksheh. Rashi (s.v. ve-eilu) explains that all forms of chametz mentioned by the mishna are subject to bal yera'eh. Tosafot (s.v. ve-eilu), however, disagree. The debate between Rashi and Tosafot may be dependant upon our question. According to Rashi, although the punishment may be different, our relationship to chametz nuksheh is no different than our relationship to chametz gamur, and bal yera’eh thus applies. Tosafot, however, view chametz nuksheh as a separate and qualitatively more lenient category, regarding which not all of the laws of chametz apply.
R. Yehuda, as noted above, believes that chametz nuksheh is only Rabbinically prohibited. The Rishonim debate whether one must rid oneself of chametz nuksheh before Pesach according to R. Yehuda (Ran, Pesachim 13a s.v. le-fikakh) or not (Tur 442).
While some Rishonim (Ba’al Ha-Ma’or and Ra’avad, Pesachim 13a in the Rif) rule that chametz nuksheh is prohibited mi-deoraita, in accordance with R. Meir’s opinion, most Rishonim rule in accordance with the view of R. Yehuda, who views chametz nuksheh as a Rabbinic prohibition.
The Shulchan Arukh (459:2, 447:12) rules that chametz nuksheh is prohibited to eat mi-derabbanan. The Magen Avraham (442:1) and Mishna Berura (442:2) conclude that one should dispose of chametz nuksheh before Pesach.
According to some Rishonim, one example of chametz nuksheh is matza ashira, commonly referred to as “egg matza.” The question of the permissibility of matza ashira on Pesach begins with an apparent contradiction between two sources that discuss dough which was made from flour and liquids other than water.
On the one hand, the gemara (Pesachim 35a-b) cites a view that implies that flour kneaded with fruit juice does not leaven:
Rabbah bar Bar Chanah said in the name of Reish Lakish: [As to] dough which was kneaded with wine, oil or honey, karet is not incurred for [eating it in] its leavened state… R. Idi bar Avin awoke [and] said to them: Children! This is the reason of Reish Lakish, because they are fruit juice, and fruit juice does not cause fermentation.
On the other hand, another passage (Pesachim 36a) strongly implies that flour mixed with wine, oil, or honey does leaven, and one who eats it may even incur the punishment of karet.
Surely it was taught: Dough must not be kneaded on Passover with wine, oil, or honey. If one did knead it, R. Gamliel said: It must be burnt immediately, while the Sages say: It may be eaten.
The Rishonim discuss how to reconcile these two seemingly contradictory passages, one which implies that fruit juice does not cause leavening and the other which implies that it does.
Rashi (36a, s.v. ein lashin) explains that flour mixed with these liquids ferments very quickly. Therefore, according to R. Gamliel, it should be burnt immediately. The Sages believe that although this mixture ferments quickly and one should therefore not mix these liquids with flour, since one who is careful can actually prevent the dough from leavening, the dough is permitted be-diavad. Rashi further explains that when the gemara (35b) teaches that “fruit juice does not cause fermentation,” it means that this mixture cannot become full chametz. However, it does become chametz nuksheh and is therefore still prohibited.
Rabbeinu Tam (Tosafot 35b, s.v. u-mei peirot) disagrees. He accepts the gemara’s assertion that “fruit juice does not cause fermentation;” therefore, matza made with fruit juice may be eaten on Pesach. The other gemara (36a), which instructs one not to make dough by mixing flour and other liquids, refers to a case in which one mixes water with the fruit juice, which may in fact accelerate the leavening process, although the final product, a type of chametz nuksheh, would only be prohibited mi-derabbanan,
The Rambam (Hilkhot Chametz U-Matza 5:2) agrees with Rabbeinu Tam and explains:
The five grains, when there are kneaded with only fruit juice and without any water, do not reach leavening. Even if one lets the mixture rise the entire day until the dough becomes swollen, it is permissible to eat, because fruit juice does not ferment; rather, it merely decays (masrichin).
The Rambam, however, disagrees regarding a case in which one added water to the fruit juice. He writes:
This only applies if there was no water mixed [with the juice]. If they are mixed with water, then they can become chametz.
The Rambam maintains that by adding water to the juice, the mixture may be leavened completely and become chametz gamur (not only chametz nuksheh).
Regarding matzot made from flour and eggs, Tosafot (35b, s.v. u-mei peirot) record that Rashi was unsure whether we should equate dough made of flour and fruit juice to dough made with eggs. Rabbeinu Tam disagrees; such a mixture is not considered chametz. Rabbeinu Tam would even eat “egg matzot” after the fourth hour on the eve of Pesach.
R. Yosef Karo (Shulchan Arukh 462:1-4) rules in accordance with the view of Rabbeinu Tam and the Rambam, who permit matzot made with fruit juice. The Rema, however, concludes that Ashkenazim should refrain from eating matza ashira, but the elderly and sick may eat matza ashira when necessary.
To this day, Sephardic Jews eat matza ashira for the duration of the festival (except for the mitzva of akhilat matza on the first night), while Ashkenazic Jews refrain from eating matza ashira. Some Sephardic Jews refrain from eating matza ashira during Pesach out of fear that the egg matza or other matza ashira products contain water. The Mishna Berura (15) explains that Ashkenazim are concerned with the opinion of Rashi, and are also concerned that the fruit juice mixed with the flour contains some water as well. He adds (18) that one may keep matza ashira in his possession until after the festival.
Inedible Chametz and Chametz not Fit for Canine Consumption (Nifsal Mei-Akhilat Kelev):
We learned above that chametz that was never fit for human consumption is considered chametz nuksheh; mi-de-rabbanan, one may not eat it or even keep it in one’s possession for the duration of Pesach.
What is the definition of “unfit for human consumption”?
The Magen Avraham (442:1) insists that if the chametz was not fit at all for human consumption, it would not even be considered chametz nuksheh. Indeed, other prohibited foods that are not edible are generally not prohibited (Avoda Zara 67b – 68a). Chametz nuksheh refers only to mixtures that are barely edible. The Minchat Barukh (44) disagrees, arguing that if chametz which is barely edible is permitted mi-deoraita and prohibited mi-derabbanan, then the laws of chametz are actually more lenient than the laws of other prohibited foods, which are prohibited mi-deoraita even if they are barely edible!
In any case, chametz which was edible before Pesach must be burnt. Even if the chametz spoiled and became inedible, if the chametz has not become unfit for canine consumption, it must be burnt. The gemara (Pesachim 45b) teaches:
If a loaf went moldy, he must destroy it, because it is fit to crumble and leaven many other doughs with it… Our Rabbis taught: If a loaf went moldy and it became unfit for human consumption, yet a dog can eat it, it can be defiled with the uncleanness of eatables, if the size of an egg, and it may be burnt together with an unclean [loaf] on Pesach.
As long as this loaf is still fit for canine consumption, it must be destroyed. The gemara elsewhere (21b), however, rules that if chametz is severely burnt before Pesach, it is permitted on Pesach.
Rabba said: If he charred it [in the fire] before its time, benefit [thereof] is permitted even after its time.
Tosafot (ibid. s.v. charkho), along with most Rishonim, assume that this gemara refers to chametz that has been so severely burnt that it is no longer fit even for canine consumption.
The Rishonim disagree as to whether this burnt chametz may be eaten, or only owned. The Ritva (ibid.) writes that the gemara only mentions hana’ah (deriving benefit) and not eating, as it is not normal for a person to eat burnt bread. The Ran (Pesachim 5b in
Some wish to say that not only hana’ah is permitted, but eating as well, as it is akin to dirt. But this does not seem correct, Even though this person’s intention [to eat the burnt chametz] is nullified in contrast to the intention of most people, still, since he eats it, it is prohibited.
The Taz (442:8) explains that the Rosh prohibits eating this spoiled chametz, which is permitted to derive benefit from, from the principle of “achshevei." By deliberately eating this chametz, one has elevated its status, and, mi-derabbanan, rendered this chametz fit for consumption. The Taz and Mishna Berura (43) assume that that Shulkhan Arukh agrees with the Rosh.
We will discuss the ramifications of this principle as they relate to medicines and cosmetics in a future shiur.
Incidentally, the Rishonim debate whether the principles discussed above apply to se’or. The Ra’avad (Hilkhot Chametz U-Matza 1:2) rules that one does not need to destroy se’or which is nifsal me-akhilat kelev. Others, who do not distinguish between se’or and other chametz, apparently disagree.
Next week we continue our discussion of the definition of chametz, focusing upon chametz mixtures (ta’arovet chametz).
 Dr. B. P. Munk, in an essay printed in Techumin (1:97-99), describes the chemical difference between a process of chimutz (becoming chametz) and sirchon.