No drinking alcohol at all.
If I am given two glass of water; one with poison and one without, I will avoid drinking of both. In other words, I will not take that action. Similarly, If I am in doubt about certain action might or might not break a precept, I will avoid doing that action. In the end, I gain nothing from it.
Also taking one glass can lead to having to take another hence become intoxicated. So itIn general; As seen in Karaṇīyamettā Sutta, (Karaṇīyam, "(This is best not to take anywhat) should be done).")
Do not do the slightest thing that the wise would later censure
@Suminda Sirinath Salpitiko also pointed out that
As"As for the use in some buddhist traditions 2nd Buddhist councilsSecond Buddhist council since some monks started drinking beverages which were in the process of fermenting. This has been rejected by the Theravada branch of monks in the 2nd council though the other sect also did have their Council. So not drinking at all is the best interpretation."