16.25. SJIOER ACHILAT PRAS?

We have now seen that in order to fulfill the mitzva of eating matza, as well as any other Torah commandment governing eating, one must eat at least a kezayit. One condition must now be added: it is only considered a single act of eating if it is completed within the amount of time it takes to eat half a loaf of bread, or a shi’ur akhilat pras. If one eats half a kezayit, waits ten minutes, and then eats another half a kezayit, it is as if he has only eaten half a kezayit, and hence he has not fulfilled the mitzva (SA 475:6).

In the past, people would bake loaves of bread that would feed one person for a day – half a loaf (a pras) at each of the two main meals.

Our long exile has caused disagreement among poskim over the precise size of a pras: according to Rambam, it is the volume of three eggs, and according to Rashi, four eggs. Several leading Aḥaronim tried to estimate how long it takes to eat a pras, and many views have been offered: nine minutes (Ḥatam Sofer), seven and a half minutes (Arukh La-ner), seven minutes, six minutes, five minutes, and four minutes (R. Ḥayim Naeh and Kaf Ha-ḥayim).

However, all this applies be-di’avad, because le-khatḥila one should eat the matza continuously, and whoever does so certainly fulfills his obligation. In addition, there is no need to look at the clock while eating the matza, because any ordinary person who eats casually but without interruption will certainly finish eating a kezayit within the shi’ur akhilat pras. Even a slow eater, if he does not stop to do other things, will assuredly finish eating a kezayit within a shi’ur akhilat pras, because a pras is eight or nine times the size of a kezayit, and it is inconceivable that one who eats a kezayit without stopping will not finish in the time it takes to eat eight or nine times that amount.[22]

[22]. Volgens Rashi is een pras de grootte van vier eieren, en volgens Tosafot is een kezayit een half ei. Een pras is dus acht kezayitiem. Volgens Rambam is een pras de grootte van drie eieren, en elk ei is iets meer dan drie kezayitiem. Een pras is dus iets meer dan negen kezayitiem. Iedereen die ontspannen eet, op voorwaarde dat hij niet pauzeert of overmatig treuzelt bij het eten, zal zeker in staat zijn om de kezajit binnen een shi’ur akhilat pras af te maken; er is dus geen noodzaak om op iemands horloge te kijken tijdens het eten.