Can I crush garlic on Shabbos for a dressing?
Spices may not be crushed on Shabbos and one who grinds even one kernel with a utensil normally used for this transgresses a Torah prohibition (tochein).
Generally, if one does a melacha with a shinui, it is still forbidden miderabanan. Yet, Chazal permitted crushing spices when done with a major shinui.
Crushing spices with the handle of the knife constitutes a major shinui and is allowed.
Some poskim require the bottom utensil also be irregular — e.g., a regular bowl instead of a designated mortar — so there is a double shinui. The Alter Rebbe implies that it’s best to be machmir.
In the permitted manner, one may crush even a lot of spices at a time. Some poskim permit it even long before the meal, provided it’s for eating on Shabbos, while others are machmir that it should be shortly before the meal.
The Alter Rebbe rules that one may not cut spices finely with a knife, even with the intention to eat them immediately. Unlike with vegetables, where some hold this is considered “derech achila,” spices are not eaten alone, and crushing them cannot be considered a “part of eating.”
(Some give another reason since spices can’t eaten without being ground, and unlike vegetables all opinions agree that spices are subject to tochein.)
This stricter status applies to all ingredients not eaten alone. Acharonim specify black pepper, cinnamon, parsley, horseradish, salt, sugar, and the like.
Spices that are eaten alone, such as garlic and hot pepper, have the same status as vegetables, and may be sliced finely to be eaten immediately (according to one opinion – see issue 815).
RABBI CHAIM HILLEL RASKIN ROV OF ANASH - PETACH TIKVA
לזכר נשמת מרת חוה לאה בת ר' שמשון הכהן ע"ה
