[Avodah] kezayit - weight or volume

[Micha Berger]

On Sun, Sep 08, 2013 at 10:09:02PM +0300, Eli Turkel wrote:
: We have discussed in the past whether the size of zayit is measured by
: weight or volume. I found this from Rav Rimon (Gush)

Wow this is huge tropic drift! Still, since you reraised the subject...

It's clear the kezayis is a measure of volume, as we shouldn't have needed
the Rambam and Magid Mishnah to prove. However, there is an old tradition,
predating the Rambam, to estimate volume using the expected weight of
a kezayis of matzah. So, the Rambam reminds the masses (pun intended)
that it's only an estimation method, not that the shiur is a weight.

Ashkenazim don't have such a history, so we use volume, although really
most of us rely on VERY ROUGH estimations based on area.

And then Sepharadim end up split, whether to use the age-old measuring
system, estimating based on weight (ROY) while Teshuvos Shemesh holds
that Sepharadim should also use whatever measuring scheme works best --
which happens to be measuring the volume using rulers. (Given the size of
safety margin built-in to using the weight of a kezayis of water rather
than a kezayis of dough.)

AISI, the machloqes among Sepharadi acharonim is about whether the
ubiquity of rulers and the decrease in commonality of scales should
change the norm or if the water weight over-estimation has been enshrined
as minhag.

GCT!
-Micha

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