3,340. Pressing Unclean Olives and Grapes
Terumos 12:10
If a Yisroel performs the labor of preparing his produce while ritually unclean, we may not harvest grapes with him, and we certainly may not tread grapes with him, because the terumah will be rendered unclean. One is permitted, however, to carry barrels to and from the wine vat for him.
Terumos 12:11
If olives and grapes are rendered ritually unclean, we may squeeze them and take terumah from the oil or wine. If they were rendered unclean after being designated terumah, they should be squeezed in volumes smaller than an egg. In such cases, the resulting liquids may be drunk by kohanim. Not only that, such liquids were fit for use as libations on the altar. This is because the liquid is considered separated within the fruit. The reason the Sages said to squeeze the fruit in volumes smaller than an egg is out of concern that if one uses more, the liquid would be rendered unclean from the larger-sized volume of fruit. If the fruit has third-degree impurity, they may be tread in the vat and the resulting liquid can be used for pure terumah. This is because third-degree impurity doesn’t generate fourth-degree impurity in terumah, as we will discuss IY”H in Hilchos Shaar Avos Hatuma.