Keeping kosher for Passover means abstaining from hametz, the fermented products of five principal grains: wheat, rye, spelt, barley and oats. Though matzah, the unleavened bread eaten on Passover, is made from grain, it is produced under highly controlled conditions to ensure that it does not ferment.

Ashkenazi Jews who keep kosher for Passover have also traditionally avoided eating kitniyot, a category of foods that includes corn, rice, beans and lentils, though the Conservative movement’s rabbinic authorities overturned the kitniyot prohibition in 2015. Sephardic Jews do not abstain from kitniyot. A minority of Jews add an additional stringency by avoiding “gebrochts” — unleavened matzah products that become wet, such as matzah balls or matzah meal.

Among observant Jews, it is common practice to avoid most processed food that is not explicitly labeled kosher for Passover. This is true even for products like cheese or juice that do not contain any hametz , but may have been processed in a plant alongside products containing hametz. Some products that are kosher year-round are modified slightly to be kosher for Passover — most famously Coca-Cola, which substitutes cane sugar for corn syrup in some regions over the holiday and is marked by a distinctive yellow cap.

A guide to kosher-for-Passover foods is published each year by the Orthodox Union, which also maintains a searchable database of Passover foods on its website. The O.U. also has information on food products that can be used without explicit Passover certification.

There are a range of additional practices common to Jews who keep kosher for Passover. Chief among them is ridding the home of any hametz products. This is typically done in the days leading up to Passover when homes are cleaned of all hametz. For hametz products that are too valuable or difficult to discard, it is also possible to sell the hametz to a non-Jew. Generally, a rabbi performs this service on behalf of his congregants and then repurchases the hametz for them when the holiday concludes. In these cases, the seller rarely delivers the food to the purchaser, but instead packs it away.

Making a kitchen kosher for Passover is an elaborate process. Countertop surfaces and sinks are either kasher ed (made kosher) with boiling water or covered for the duration of the holiday, depending on the material. Metal pots and utensils can usually be kashered with boiling water, and various appliances have their own requirements. The O.U. has a guide to kitchen preparation.

Given the difficulties involved, many observant Jews maintain separate Passover cookware, dishes and utensils that are used only during the holiday.

Many Jews who do not follow all these restrictions nonetheless make some dietary changes in honor of the holiday. Some people avoid eating hametz but do not thoroughly purge their kitchens of it, while others cut out bread and pasta, yet continue to eat some traditionally forbidden items.

In recent years, many affluent observant Jews have opted to avoid the rigors of cleaning their kitchen for Passover by going on special kosher-for-Passover cruises or to kosher-for-Passover resorts. The trend, while costly, not only makes the holiday easier to observe, but often provides a welcome opportunity for an extended family to get together without the burden of having to host and cook for large numbers of guests.