May I grind pepper on Yom Tov?

In respect of grinding, halacha makes a distinction between foods grown in the ground and other foods; foods that spoil when ground before Yom Tov, foods that will not spoil but will not be fresh and foods that will not be affected if ground before Yom Tov.

But surely grinding prior to kneading, is totally forbidden?

You are referring to the famous statement that melachos prior to kneading such as reaping, squeezing etc. are prohibited. Indeed the Shulchan Aruch states [1] that grinding – tochen is prohibited on Yom Tov and yet we are saying that certain foods may be ground on Yom Tov. We will b’ezras Hashem explain.

Is grinding ossur mid’oraisso or mid’rabanan?

It is a machlokes haposkim (a dispute).

The shulchan Aruch [2] is of the opinion that it is ossur mid’rabanan, because Chazal were concerned lest one totally involves oneself with melachos ochel nefesh and not have time to enjoy Yom Tov. They therefore forbade melachos (even though they are for ochel nefesh) such as grinding because one normally grinds wheat etc. in bulk.

One may grind foods that are normally ground before use, such as avocado and bananas, as there was no need to prohibit such an action.

Other poskim [3] argue saying that the prohibited melachos are ossur mid’oraisso, because they are normally done in bulk for extended periods and the torah only permitted melachos that are done prior to consuming, such as baking and grinding certain herbs and spices. The basic rule is that from kneading onwards melachos are permitted.

Can you please categorize the various foods?

As mentioned, foods that would spoil if ground before Yom Tov may be ground on Yom Tov in the regular manner.

Bananas and avocado may be ground with a fork. [4]

Onions may be diced into small pieces with a large knife.

Apples may be grated on a grater.

Based on the above this is permitted because one does not normally grind these items too far in advance because they would spoil.

Which foods would not spoil but would not be fresh?

Items such as coffee, horseradish and spices may be ground on Yom Tov but with a shinui – deviating from the regular manner. These items are much tastier when ground prior to use but will not spoil if ground in advance. Consequently Chazal permitted it albeit with a shinui.

Hence, if one normally grinds horseradish onto a plate, one should grind it onto the table or onto paper. [5]

The heter to grind b’shinui or at all is only for Yom Tov, not for after Yom Tov.

Spices And Pepper

The Mechaber writes that one may grind spices in the normal manner, i.e. with a pestle and mortar, but pepper may not be ground in a pepper mill because it is an uvda d’chol – a weekday action. He is lenient because he understands that these items lose flavor when ground in advance.

The Rama appends that it is customary to deviate from the norm when grinding spices, that means that one may not use the pestle and mortar rather one should grind pepper on a plate etc.

The reason for this stringency is because some poskim rule that spices may not be ground on Yom Tov, even though they lose flavor, unless one was unaware that one would need pepper on Yom Tov. In other words, one should have prepared in advance. Since we l’chatchila follow that opinion, halacha is that these items must be ground b’shinui. [6]

The Mishna Berura adds those items that spoil when ground in advance, as mentioned above, may be ground without a shinui.

What about items that do not lose flavor?

Items that do not lose flavor should be ground before Yom Tov, such as nuts and sea salt (regular table salt is ground and if crystallized may be ground again) and one should not rely on the halacha that permits grinding b’shinui. If however one forgot to grind them before Yom Tov or miscalculated and one requires more than planned, one may grind them b’shinui as mentioned above. [7]

As mentioned, a pepper mill may not be used on Yom Tov and grinding is permitted for same day only.

May one grind eggs and meat on Yom Tov?

These items are not grown in the ground and may be ground in the regular manner. There may be room in this case to use a kitchen grinder and a rav should be asked. [8]