Chametz 101: What’s Biblically Banned on Passover—and What’s Rabbinic

Quick primer

- Only the five grains can become leavened: wheat, barley, oats, rye, and spelt.

- To reach leavening, three conditions are required:

1. The five grains                                                

2. Mixed with water                               

3. The grain-and-water mixture sits for about 18 minutes without kneading

- As long as the dough is being kneaded (even all day), it will not leaven.

"Chametz"

- Chametz is one of the five grains that has leavened—meaning it sat with water for a certain time and leavened—and is fit for a dog to eat.

- On Passover, chametz is a Torah-level prohibition.

"Se’or"

- One of the five grains that leavened and was once edible, but then leavened so much that it is no longer fit for a dog to eat, and it now causes other doughs to leaven. Se’or is essentially "yeast."

- Even though this is no longer edible to a dog, it remains a Torah-level prohibition because it can facilitate making food leaven.

"Matzah"

- Matzah is one of the five grains mixed with water and baked before it leavened.

"Chametz nukshah"

- One of the five grains in which leavening began, but from the outset it was not fit for a dog to eat except under duress—for example, paste or glue made from flour, which is not edible from the start.

- Chametz nukshah is not biblically prohibited; it is a rabbinic prohibition.

"Chametz that is no longer fit for a dog"

- If chametz became moldy or rancid before the time it becomes prohibited and is so inedible that even a dog would not eat it, it has no status of chametz at all; it is neither biblically nor rabbinically prohibited and is completely permitted on Passover, such as:

- All cleaning products, even if they contain some chametz derivative, are completely permitted on Passover with no concern, since a dog cannot eat them, and they require no Passover certification.

- Cosmetics, makeup, lipstick, perfume, shoe polish, toothpaste, cigarettes, and similar items.

- Strictly speaking, there is no need to buy Passover-certified toothpaste, even if it has a pleasant taste, since it is not fit for a dog to eat.

"On Passover, chametz prohibits a mixture in any amount"

- Chametz is not prohibited only when it stands alone; even in a mixture it is prohibited. That is, if chametz falls into a dish, the entire dish is forbidden even though the chametz is blended in and not present on its own.

- However, there is a difference if the chametz is mixed in before Passover or during Passover:

- Mixture with chametz before Passover: forbidden unless there is sixty times against it. Meaning: if the chametz fell into the mixture before Passover and there is sixty times its amount in the mixture, the chametz is nullified in the mixture—standard 1-in-60 nullification—and the food is permitted to eat on Passover.                                                                                        

- Mixture with chametz during Passover: prohibited in any amount. That is, even a single grain of chametz that fell into a mixture on Passover  itself forbids the entire dish, even if there is a thousand times more than it.

For example: A single wheat kernel that fell into a dish during Passover forbids the whole dish, even if the dish is a thousand times the size of the kernel.

"Chozer v’ne’or"

- If chametz mixed into a mixture before Passover and was nullified in sixty, there is a dispute among the authorities whether, during Passover, the nullified chametz “reawakens.” In other words: since on Passover chametz prohibits in any amount, does it regain force despite having been nullified before Passover and forbid the mixture:

-  For Sephardim: there is no rule of chozer v’ne’or. Therefore, any chametz that fell into a mixture before Passover and was nullified in sixty no longer renders the mixture forbidden, and it is permitted to eat on Passover l’chatchilah.

-  For Ashkenazim: there is a rule of chozer v’ne’or on Passover. Even if chametz fell into a mixture before Passover and was nullified in sixty, when Passover arrives the nullified chametz “reawakens,” regains force, and forbids the entire mixture during Passover.

"Noten ta’am lifgam"

- For all foods the Torah prohibits—such as non-kosher animals—not only the substance itself (the body of the prohibition) is biblically forbidden, but even its taste. For example, if a pot of water was used to cook a non-kosher animal and the animal was then removed so only its flavor remains in the dish, that dish is still forbidden.

- Likewise, prohibited flavor absorbed into a pot is also forbidden. However, only if the taste is pleasant and improves the food is it prohibited; if the taste is degraded or rancid, it is not prohibited biblically.

- The Sages nevertheless added a rabbinic restriction and forbade, l’chatchilah, even a degraded taste—permitting it only b’di’avad. Therefore:

- A prohibited taste that is noten ta’am leshevach — prohibited.

- A prohibited taste that is noten ta’am lifgam — forbidden l’chatchilah but permitted b’di’avad.

- Flavor absorbed in a pot turns from pleasant to degraded after 24 hours.

- Example: If a pot was used to cook non-kosher meat, then even if the pot is thoroughly washed it remains forbidden to cook in it until it is kashered properly. However, if by mistake food was cooked in that clean pot after 24 hours had passed since the non-kosher cooking, the food is permitted, because the flavor that transferred from the pot to the food is noten ta’am lifgam (an off-taste).

- With chametz as well, not only the substance of the chametz is prohibited on Passover, but even its taste—if it improves the food.

- There is a dispute among the authorities regarding chametz: Is noten ta’am lifgam with chametz permitted on Passover b’di’avad, as with other food prohibitions, or did the Sages rule stringently and forbid even noten ta’am lifgam on Passover b’di’avad? In practice:

-  For Sephardim:Noten ta’am lifgam is permitted on Passover only b’di’avad.                           

-  For Ashkenazim: Noten ta’am lifgam is forbidden on Passover even b’di’avad.

- Example illustrating the ruling: Someone mistakenly took a clean pot that was not kashered for Passover (i.e., a pot used for chametz before Passover, cleaned well but not kashered) and cooked Passover-permitted food in it. Is the food permitted b’di’avad or not?

-  For Sephardim: If no chametz was cooked in that pot for more than 24 hours, the taste in the pot is degraded, and therefore the food is permitted b’di’avad.

Since the absorbed chametz flavor has deteriorated, any noten ta’am lifgam is permitted b’di’avad—even on Passover.

-  For Ashkenazim: Even though the absorbed taste in the pot is degraded, the food is forbidden, since noten ta’am lifgam is prohibited on Passover even b’di’avad. 

- All leniencies of noten ta’am lifgam apply only b’di’avad—that is, after the fact. L’chatchilah, relying on noten ta’am lifgam is forbidden.

- This is not the place to spell out the precise definitions of noten ta’am lifgam and noten ta’am leshevach. For any question, consult a competent Torah scholar; the above is only to provide general background to the terms.

"Matzah sheruyah"

- When baked matzah is moistened with water or another liquid, most authorities permit this l’chatchilah, since once the matzah is baked, it will not leaven again.

- However, there are Chassidim who are stringent not to let baked matzah come into contact with water. This stringency stems from two concerns:

1. Perhaps the matzah was not fully baked, and there may be spots that could still leaven.

2. Perhaps flour adhered to the outside of the matzah, which would leaven upon contact with water.

- In practice: We do not follow these stringencies; l’chatchilah it is permitted to soak matzah in water on Passover without any concern. Nevertheless, some Chassidim observe these stringencies.

- Someone who has the practice not to eat matzah sheruyah and wants to set aside that practice and eat it:

- If they accepted it as a vow not to eat matzah sheruyah: they should perform annulment of the vow with a qualified authority.

- If they believed that eating matzah sheruyah is intrinsically prohibited: there is no need for annulment; they may eat matzah sheruyah without annulment.

"Matzah ashirah"

- The five grains, when combined with water, can leaven under certain conditions (as explained above).

- What if one of the five grains is mixed with fruit juice (mei peirot—pressed fruit)? According to the vast majority of authorities, combining one of the five grains with fruit juice alone does not cause leavening (except for Rashi, who holds that fruit juice can also leaven). However, according to all opinions, if the fruit juice contains even a small amount of water, it will leaven more quickly than with water alone.

- Matzah kneaded with fruit juice only or wine only is called "matzah ashirah".   

- For Sephardim: matzah ashirah is permitted on Passover l’chatchilah, without concern.

- For Ashkenazim: matzah ashirah is prohibited on Passover for two reasons:

1. Out of concern for Rashi’s view that fruit juice leavens like water.

2. Lest water was mixed with the fruit juice, which would then cause leavening.

- Even for Ashkenazim who prohibit matzah ashirah on Passover, the elderly, the ill, or children who have not yet reached the age of education may eat matzah ashirah.

- "Papushado" cookies are made with fruit juice or wine only; therefore they are permitted for Sephardim l’chatchilah on Passover without any concern.