Passover is unique in that not only can’t we benefit from chametz during the holiday, but we can’t even own it. To discourage would-be chametz hoarders, the sages established a rule: any chametz owned by a Jew during Passover cannot be used or consumed even after the holiday ends. This rule applies even if the chametz was owned unintentionally, and even if it was owned by another Jew during Passover and you took ownership of it after the holiday.1

This chametz, known as chametz she’avar alav haPesach (literally "leaven that has passed through Passover"), is off-limits. However, chametz owned by non-Jews throughout Passover doesn't fall under this rule. So selling your chametz before Passover and purchasing it back afterward is perfectly acceptable.

The most common manifestation of this prohibition is purchasing chametz in Jewish-owned stores shortly after Passover. So here are some things to keep in mind when shopping after Passover.

What’s Included?

In addition to clearly identifiable chametz items such as bread, pasta, cookies, crackers and pretzels, beware when purchasing many breakfast cereals, oatmeal, most soy sauce varieties, beer, whiskey, and, according to many, even flour (since commercially available wheat is usually tempered in water before milling, flour has the status of chametz2).

However, you don’t need to worry about kitniyot (corn, rice, beans, etc.), which Ashkenazic Jews avoid eating during Passover but are not considered chametz.

Jewish-Owned Stores

If a store sold its chametz before Passover, any purchases made after the holiday are fine. But if a storekeeper didn’t sell their chametz or acquired new chametz during Passover, those items are forbidden. For Jewish food manufacturers and distributors, the situation is more complex: if they continue supplying chametz during Passover, any chametz in those stores after Passover is considered chametz she’avar alav haPesach.

What Is “Jewish” Ownership? Does Stock Count?

If a Jewish person (or a group of Jews) owns more than 50% of a company, or if he has a minority interest but is actively involved in the company, the business relationship is seen as a partnership, potentially raising issues with chametz she’avar alav haPesach. Thus, for example, if a Jew is a minority partner but is also the manager of the company, the enterprise is treated as a Jewish business.3 However, merely holding a minority share without any active role does not affect the halachic status of the company’s chametz assets during Passover.

Many kosher certification organizations and local rabbis work to ensure Jewish-owned businesses sell their chametz for Passover. However, not all Jewish companies do so. Many kashrut organizations give out an annual list of local companies and supermarkets that are or aren’t problematic.

Waiting It Out

If you know that the store (or company/distributor) is indeed Jewish-owned and did not sell their chametz, then you may have to wait until there is enough turnover to be confident that your purchases were not owned by them over Passover.

According to many kashrut organizations, the average turnover for a well-run supermarket and supplier is approximately two weeks (and for smaller stores, maybe three weeks). So, if a Jewish supplier delivers its last delivery of chametz she’avar alav haPesach two weeks after Passover, and if you give another two weeks for the turnover from the retailer's shelf, you can estimate that four to five weeks after Passover, there will no longer be problematic food items in the Jewish-owned store.

Furthermore, although these numbers are just estimates, many are of the opinion that it's permissible to buy chametz from a store once there's a 50-percent chance the store obtained it after Passover. Why? Because despite the severity of the prohibition, chametz she’avar alav haPesach is a rabbinic, not biblical, prohibition, and the principle of safek derabbanan lekula allows leniency when unsure about a rabbinic restriction.

Practically, this means that a “significant doubt” already exists 2-3 weeks after Passover (and in case of need, one can be lenient), and in 3-6 weeks one can almost be certain that the items were obtained after Passover.4

Bourbon, Whisky and Other Spirits

Products like whiskey, bourbon and beer, which can take years to produce, are forever prohibited if the manufacturer is Jewish and doesn't sell its chametz. Keeping track of such products is crucial, and many kosher organizations provide lists of beverages to avoid.