The Passover holiday is a time to celebrate our rich heritage and affirm our commitment to the continuity of our traditions. The exodus from Egypt was the point in our great history when we were freed from bondage to man, and became a nation of God with the subsequent acceptance of the Torah at Sinai.
What has sustained us as a nation and enabled us to carry on throughout the millennia has been our observance of the Torah and its mitzvot, replete with their many details that define our way of life and preserve our identity. During Passover, this notion expresses itself through required measurements of the special foods we eat during the holiday. These basic measurements and the careful adherence to them are integral to our heritage. Indeed, the Talmud states that halachic measurements are a part of the unique laws that were given to Moshe Rabbeinu at Sinai.
The general measurement of food items used in the performance of mitzvot is minimally a kezayit, the size of an olive by volume. Liquids are measured by a revi’it, an ancient measure equaling a few liquid ounces.
There are some variances among halachic authorities as to how the precise measurement should be calculated, but the minimally recommended size is approximately 29 cubic centimeters. Although strictly speaking, the Torah-level mitzva of matza requires one to eat the measurement of a single kezayit, there is a rabbinic requirement to consume a total of five kezeitim at different intervals of the seder. The first two portions are eaten together, one associated with the benediction of hamotzi with the other associated with the benediction of al achilat matza.
The third kezayit is eaten as part of the traditional korech sandwich from the sage, Hillel, which serves as a reminder of the Beit Hamikdash (Holy Temple). The fourth and fifth kezeitim are eaten together at the end of the festive meal as part of the afikoman. The fourth kezayit is associated with the korban Pesach, while the fifth kezayit is a reminder of the matza that was eaten together with the korban. Ideally, the required measurement for the additional four kezeitim should be the same as the basic mitzvah of matza mentioned above. However, since these four kezeitim are rabbinic requirements, in an extenuating circumstance there is room for leniency to eat less.
Today, with the absence of the Beit Hamikdash, the korban Pesach (paschal lamb) is not brought and therefore its interdependent sister mitzva, maror (bitter herb), is not a Torah-level precept, but is currently a rabbinic ordinance. This is because our Sages mandated that one must still eat the traditional bitter herb independently. Therefore while the minimal amount of maror required to consume at the seder is also a kezayit, there are some variances among halachic authorities as to how this measurement should be calculated. Moreover, some authorities calculate the measurement differently for mitzvot de-rabbanan. The minimal size given is approximately 19.3 cubic centimeters, which can be limited to just a single, large leaf of romaine lettuce. Medium or small leaves of romaine lettuce will respectively amount to approximately three-fifths or one-fifth of the required amount. Large romaine stalks are approximately half a kezayit, while small stalks are roughly one-quarter’s worth. A single endive is between one-half to one-quarter of the required amount, depending upon whether the leaf is large, medium, or small. A filled one ounce shot glass of ground horseradish constitutes a kezayit.
The requirement of drinking four cups of wine is rabbinic in nature and the minimal measurement required for the four cups is a revi’it for each cup. There are some variances among halachic authorities as to how this measurement should be calculated, but the minimal size given is approximately three ounces. It should be noted that if one’s cup holds more than a revi’it, one should try to drink the entire cup or at least most of it.