Continuing the discussion of whether we need to be concerned with changes in the status quo, the Mishna on our daf discusses a case where a person sets aside fruit from which he will bring all of his terumot u’ma’asrot (various tithes). Specifically, he puts aside some of his harvested crop and whenever he harvests more of that type of fruit he proclaims that the tithes will be taken from the fruit that has been set aside for that purpose. The Mishna teaches that he can rely on the fact that that fruit remains extant and is available for tithing. Rabbi Yehuda teaches that there are three times of the year that wine set aside for this purpose must be checked to ensure that it has not become spoiled – the windy period after Sukkot, when the first tiny grapes appear on the vine, and when they begin to fill up with juice.
Rashi explains that Rabbi Yehuda’s ruling about wine is also talking about a situation where the wine that is being tithed is in a place that is separate from the wine that is stored for tithing. Our concern is that the wine may have turned to vinegar, which is considered a separate entity and cannot be used for tithing wine.
The need to check wine stems from the fact that chemical changes continue occurring in wine even after its period of fermentation. These slow changes add specific smells (usually referred to with the French word, bouquet) and tastes to the wine. For many generations – until the development of pasteurization techniques – wines were subject to the effects of bacteria and microorganisms that occasionally ruined the taste of the wine or turned it into vinegar.
Severe weather changes – especially those accompanied by a significant rise in temperature – could hasten the effect of these microorganisms and fungi, which is why it was necessary to check the wine during those times of year to make sure that the wine had not gone bad.