Beitza 14 - Giving presents on a Holiday
Since one can cook on a Holiday (Yom Tov), one is also permitted to grind spices. However, when crushing rock salt, she should do it in a manner different from weekdays. Why is salt different from spices? - Every dish needs salt, so should have thought of it and crushed it beforehand, but spices - he may decide to cook a special dish that require them, on the spur of the moment. Another reason: spices begin to loose flavor right after they are ground, so it is impossible to prepare them before the Yom Tov.
Is there any practical difference between the two reasons? - Yes! - if he knows which dish he will cook. According to the first reason, he should have prepared the spices and cannot grind them now; according to the second reason, anyway they would loose their pungency, so could not prepare beforehand and is therefore allowed to grind them now.
One should not send presents to his friend on a Yom Tov, since people might see them and think that he is sending good to the market to sell. The only things that are allowed are ready-made portions of food. This is the opinion of Beit Shammai. However, Beit Hillel are not concerned about it, and allow sending animals and fowl, alive or slaughtered, also wines, oils and fine flours - provided that it is not carried by a caravan of three people, because then it does look like trading.
Art: Preparing spices for market By Paul Saint-Jean