The Torah commands one to make a blessing after eating bread and defines 'eating' as constituting the ingestion of a 'k'zayit' (the amount of an olive). The requirement for making a brocha achrona on other types of foods uses similar criteria. To know how much of a particular food equals a k'zayit is not easy. A k'zayit is a measure of volume, or the amount of space it occupies. But Rabbi Yisroel Pinchos Bodner of Lakewood, New Jersey has researched this and come up with the answers in his book, "Halachos of K'zayis". According to Rabbi Bodner a k'zayit of herring is equal to two large pieces equaling about 29 grams and looking like they would fit onto two regular sized crackers.
"A k'zayit is a measure of volume..." Assuming, of course, that you hold that way. The Rambam didn't; he translated everything into weight. Many communities (mostly Sefaradi) followed in his footsteps, right up to Rav Mordechai Eliyahu and others in our time. Oddly, you listed a weight here in this post (29 g). If you want to be consistent with your assertion, then you should have given a volume or area; just like the folks who use those placards on erev Pesah to figure out their measures. We just use weights, as the Rambam taught.
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ReplyDeleteAccording to many poskim, a kezayis is... the size of an olive! Certainly a cracker's worth. And it's easy to understand how and why alternate views developed. See http://www.rationalistjudaism.com/2010/03/evolution-of-olive.html
ReplyDeleteWhat are the dimensions of a regular sized cracker?
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