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Weekly Shabbos Halacha Series
Halachos Series on Hilchos Shabbos

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Published by
Pirchei Shoshanim

A Project of
The Shema Yisrael Torah Network

Written by

Rabbi Dovid
Ostroff, shlita


These Halachos were shown by Rabbi Ostroff to
HaGaon HaRav Moshe Sternbuch, shlita



Questions for the Week of Va'era


Grinding cont.

What about scraping mud from ones shoes on Shabbos? Does grinding apply somewhere?

            Yes, as explained, grinding mud is a problem of and although one may gently scrape mud from ones shoes one must not grind or break up dried mud.

            Is one permitted to mash avocado onto a piece of matza or bread?

            Here one is entering the realm of grinding and we know that one is forbidden to mash or grind in the regular manner. We learned that one may grind salt or pepper on Shabbos by implementing two modifications to the process. It is permitted to crush salt or pepper with a knifes handle onto a plate or table. The normal way to mash a banana is to use a fork on a plate etc. How is this modified to enable its mashing on Shabbos?

Hagaon Rav Moshe Feinstein ztzl held [1] that bananas are not subject to the constraints of grinding because the definition of grinding is to crush an article into small pieces, which is not the case when one mashes a banana, rather it remains one piece albeit in a different form.

The Chazon Ish [2] on the other hand held that grinding applies to mashing items such as bananas as well. He held that for a child one may mash a banana with a spoon handle. [3]

Rav Moshe concludes that one lchatchila should mash a banana with a handle of a spoon (because of the Chazon Ish) and if one finds that difficult one may mash a banana with a fork in the regular manner.

It appears that Rav Shlomo Zalman Auerbach ztzl [4] was more stringent than R Moshe and ruled that one may only mash a banana with either side of a spoon but not with a fork.

Consequently, one should mash avocado with a spoon onto matza or bread.

            Does the heter to mash bananas only apply to children?

            Since one is deviating from the norm and not mashing it in the regular fashion, one may mash it for adults as well, but one should only do so prior to eating. [5]

            Is there a special leniency to mash soft fruit and vegetables?

            Some avocadoes are so soft that when one holds one part of the avocado it simply breaks off. The same happens with vegetables that have been cooking, for example in a soup, for a long time. Rav Shlomo Zalman Auerbach ztzl held that the issur of grinding does not apply to fruit or vegetables in such a state because it is as if they are already ground. [6] Naturally one must take care that the vegetables have indeed reached the required state.

            Is one permitted to slice hard-boiled eggs with an egg slicer?

            Eggs are not subject to the constraints of grinding as that they are not grown in the earth. Nevertheless one may not grate them with a grater or grinder. An egg-slicer, on the other hand, does not grind eggs, it merely cuts them in a sophisticated manner. [7] Therefore one may slice tomatoes and onions with this instrument as it is not a grinder.

            Are there any limitations as to how one is supposed to make porridge on Shabbos?

            One of the melachos of the Mishkan was kneading, where they would mix flour and water and knead it to form dough. There are many complex details regarding this melacha and we will beH try and simplify it as much as possible.

The halacha deals with two forms of mixtures, a firm mixture and a liquid one, or a and a . Making a firm mixture can often involve a biblical violation and therefore the ways to produce such a mixture on Shabbos are very limited. Making a liquid mixture on Shabbos is only an issur drabanan (a rabbinic violation) and therefore a wider range of solutions are at hand.

A firm mixture it is forbidden to mix powder with liquid to form a paste. Accordingly one may not mix humus or mustard powder with liquid to form a paste. It does not help to mix them bshinui (modify the mixing mode) because it is making a . [8]

We define a as any mixture that one cannot pour and a as a mixture that one is able to pour from one kli to another. [9]

Taking it for granted that it is forbidden to make a firm mixture on Shabbos we will concentrate on making a liquid mixture.

To answer the question we will say that a thick porridge falls into the category of a firm mixture and as such it cannot be made on Shabbos. See footnote 8.

            How is one to make a liquid mixture on Shabbos?

            Two processes are incorporated in making a mixture and both must be modified in order to permit making a liquid mixture on Shabbos. The first is pouring the liquid into the solid or vice versa and the second is the actual mixing of the two items.

Pouring if normally one would pour the liquid onto the solid, on Shabbos one must add the solid to the liquid. If normally one would add the solid to the liquid, on Shabbos one must pour the liquid onto the solid. If there is no fixed pattern the Mishna Berura says [10] to pour the liquid onto the solid. [11]

Mixing normally one mixes the solid and the liquid with a spoon. In order to deviate one may either mix them with ones finger or shake the kli. If either method is not feasible one may mix with a spoon but it must be done is a crisscross fashion, i.e. insert the spoon for example in the north of the bowl and run it southwards. Then insert it in the west of the bowl and run it eastwards etc. Continue in this fashion until the ingredients are mixed. The Chazon Ish writes that lchatchila one removes the spoon from the bowl after each run [12]

[1] " ' ' ".

[2] Chazon Ish Siman 57. Although the Chazon Ish himself on the one hand leans towards R Moshes understanding but sways from it when he discusses the banana. R Moshe finds this section of the Chazon Ish difficult.

[3] Rav Moshe questions this heter because it is only one modification.

[4] See the SSK 6:7-8 and footnote 20.

[5] Although the Chazon Ish siman 57 is referring to mashing bananas for children, it appears that it is because that is the norm as other people can do it without mashing. However, the SSK 6:8 writes that it is only permitted for people (children etc.) that could not eat it otherwise. Conversely, if it is mashed prior to eating, we can rely together with the other heteirim for mashing bananas on the opinions who permit mashing prior to eating.

[6] SSK 6:7 and footnote 18.

[7] SSK 6:3 and footnote 12.

[8] We will see later beH that when it is very necessary to make a firm mixture on Shabbos, for a baby for example, and it is not possible to prepare the solution before Shabbos there is a method it can be done.

[9] See the Chazon Ish ' : " " ', SSK 8:8.

[10] Siman 321:14 and MB57 and 66.

[11] The Chazon Ish 58:5 " argues and says that when there is no fixed pattern it is not possible to deviate from the norm and pouring is ossur.

[12] See the SSK 8:9 b.


Orchos Chaim LaRosh

" one should daven minchah early on Erev Shabbos to accept Shabbos before sunset.

It is a mitzvas Aseh according to many Rishonim to accept Shabbos before sunset. This is done by verbally saying I accept Shabbos Kodesh, and it must be done a few minutes before sunset. [1]

[1] Siman 261:2.

For a printed version, click here.



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