Commentary for Avodah Zarah 59:21

This is the same passage as above but about cooked wine. Cooked wine does not need two seals (today cooked wine can be handled by a non-Jew because we are more lenient today about wine because non-Jews do not libate. But in the Talmud they were still strict).

Boiled wine is prohibited if it belongs to the non-Jew, although as we saw, there are some leniencies with regard to it. Alontit is wine mixed with water and some balsam. If the Jew prepared the alontit, it does not become prohibited when it enters the non-Jew’s possession.

Snakes, according to this, will not put their poison into wine diluted with water. And non-Jews do not libate boiled wine.

Snakes do not put their poison into boiled wine either. Those finicky snakes!

The halakhah here is the same as above. The real life setting of the discussion is interesting. It shows rabbis learning halakhah while visiting the sick. It also shows some process of reciting a tradition and then asking another sage if it is authoritative.

Shmuel rebukes his friend Avlet for refusing to drink boiled wine.

Diluted wine is wine mixed with water. Wine was generally diluted right before it was drunk. Evidently they said that snakes do not drink diluted wine. Snakes—they take it straight up.

According to R. Papa snakes will drink slightly diluted wine. But this is contradicted by a story in which the servant protects the wine by slightly diluting it. The Talmud resolves the issue by saying that snakes will drink slightly diluted wine, but only if they do not need to endanger their lives to do so.

In this case the clever snake dilutes the wine himself!

The Talmud tries to answer that the snake will drink diluted wine only if he himself diluted it. But Rav Ashi finds this a bizarre resolution to a difficulty that involves what they perceived to be real physical danger. If the snake will drink diluted wine, then we better be careful, and not just offer resolutions as if we were dealing with theoretical issues. This is a fascinating recognition that many resolutions to difficulties in the Talmud are not based on demonstrable truth. When it comes to an academic subject, this is okay. But not when it comes to subject with immediate life and death consequences.
In the end, diluted wine is subject to the same laws as undiluted wine. Snakes drink it and non-Jews libate it. But boiled wine is not.

Snakes will not drink water next to a person, even if that person is sleeping, and even if it is night.

According to Rav only Jewish men are particularly careful about the laws of not drinking from uncovered vessels. So he won’t drink water at a non-Jew’s house. And the only reason he drinks at a widow’s house is that he assumes she follows the customs of her husband. Shmuel acted in an opposite manner, not trusting the widow but trusting the non-Jew, assuming snakes won’t be found in his house.
There is also a version where Shmuel would drink from neither house.
The impression from this piece is that not drinking uncovered water was considered part of high, educated culture and that people would question who was keeping these health restrictions, and who was not. Jewish males are assumed to keep these laws. Non-Jews and females are not.

R. Joshua b. Levi lists three types of wine that snakes won’t drink.

R. Hama has the same list but he understands it differently.

Outside of Asia, snakes won’t drink Karina. But in its place, this is just the wine that everyone drinks—snakes and humans alike. So since snakes will drink it, it does become prohibited.

The issue here is whether snakes will drink wine or non-Jews will libate wine that has grown old and formed a film over the top.