[Avodah] K'zayis as weight not volume?

[R Davidovich]

The teshuva I cited seems to say that 28 grams of matza need to be eaten,
not 28 ccs.  He even mentions using a scale to weigh the 28 grams, not 14
grams.  He mentions no conversion from mass to or from volume.  That would
make his kzayis shiur half a hand-matza, not a quarter.

Do you think he was inexact and meant cc's?

On Fri, Apr 11, 2008 at 8:55 AM, Gil Student <gil.student at gmail.com> wrote:

> I don't know what ROY says but R. Mordechai Willig also uses weight (I
> will be"H be posting his calculations early next week). The real issue
> is mass but weight can be used to calculate mass if you have the
> appropriate conversion factor.
>
> 28 ccs of water weighs 28 grams. If something has the same density as
> water and weighs 28 grams, then it has a mass of 28 ccs. Experiments
> have shown that handmade shemurah matzah has approximately half the
> density of water so 14 grams of handmade shemurah matzah has about a
> mass of 28 ccs. Therefore, if you eat 14 grams (half an ounce) of
> handmade shemurah matzah, you have eaten 28 ccs, which is a ke-zayis
> according to ROY.
>
> I believe an average handmade shemurah matzah weighs a over 2 ounces.
> So ROY's shiur of ke-zayis is under 1/4 of an average matzah.
>
>
>
>
> On 4/11/08, R Davidovich <raphaeldavidovich at gmail.com> wrote:
> > I recently read a teshuva by R'Ovadia Yosef (Yechaveh Daat 1: 16) that
> gives
> > the measurement for the k'zayis as a weight, not volume.  Instead of
> saying
> > that the k'zayis is 28cc, which comes out to about  1/6 of a hand-matza
> > according to Rabbi Heinemann's water-displacing  tests, ROY says that
>  it is
> > 28 grams, which is the approximately the weight of half a hand-matza.
>  (With
> > standard issue hand matza, you get about 8 matzos a pound, one slice is
> two
> > ounces, or 56 grams.)
> >
> > I cannot figure out how ROY turned k'zayis and k'beitza into mass!
> >
> > Does anyone have sources or answers?
> >
> > --
> > RD
> >
>
> --
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>
> Gil Student,          Yashar Books
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-- 
RD
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