Maaseros 4:3-4

Maasros 4:3

If a person takes olives from the vat, he may dip them into salt individually and eat them without tithing. If he salted several olives and put them in front of himself, they must be tithed. Rabbi Eliezer says that olives from a ritually-pure vat must be tithed in such a case (assuming that the one who takes them is ritually impure and renders the olives equally impure) but that those from a ritually-impure vat need not be tithed because they can be returned to the vat.

Maasros 4:4

Rabbi Meir says that one may drink wine over a wine vat, mixed with either warm or cold water, without tithing; Rabbi Meir b. Rabbi Tzadok says that it must be tithed. The Sages say that wine mixed warm must be tithed but wine mixed cold need not (since only the latter could be returned to the vat).