The Mishna on today’s daf is concerned whether when wine is poured into a barrel containing forbidden wine, perhaps the connection between the liquids will cause the permitted wine to become prohibited, as well. This theme leads to a number of warnings made to Jews who dealt with wine, as described by the Gemara.
Rav Ḥisda instructed the Jewish wine-dealers: When you measure wine for non-Jews, either cut off the flow or pour it in with a splash. Rava told Jews whose occupation was to pour wine: When you pour wine, let no non-Jew come near to help you, lest you forget yourselves and rest the barrel on his hands and the wine will be poured as a result of his actions and the wine be prohibited.
The Gemara relates that a man was drawing wine through a siphon consisting of a large and small tube (the Gemara refers to these as a gishta and a bat gishta). A non-Jew came and put his hand on the large tube, and Rava disqualified all the wine. Rav Pappa said to Rava (some say it was Rav Adda bar Mattana or Ravina who said to Rava), was it on account of the stream that went through the tube, from where we can learn that the stream constitutes a connection? Rava answered that it is different in this case, since all the wine is drawn towards the tubes, so it is as though the non-Jew touched all the wine in the barrel.
Mar Zutra the son of Rav Naḥman taught that it is permitted to drink wine from a vessel containing several tubes, provided the Jewish person stops first but not when the non-Jew stopped first, since the wine from his mouth will return to the vessel. Rabba bar Rav Huna visited the house of the Reish Galuta and allowed the company – which included non-Jews – to drink from a vessel containing several tubes.
We find many pictures from the ancient world that show groups of people drinking from a single vessel by means of tubes and siphons. Some suggest that the words used in the Gemara to describe this – gishta and bat gishta – are related to the Persian word “to suckle” although the philological evidence is not clear.