Vodka, brandy, tequila, whiskey, rum, gin.
These are the six base spirits used for mixing cocktails, presumably corresponding to a bartender's powers.
Probably, these are the light spheres around a bartender.
However, there were only five light spheres around the bartender just now, and after using vodka, only four remained, so Yu Liang's estimate of six base spirits didn't match.
Could it be that these base spirits are hard to replenish, reduced by one for every one used?
Given the effect of vodka just seen, it's quite possible, as the effect of vodka is rather overpowering.
Completely incapacitated for three minutes with an incredibly lasting reduced health status for twenty-four hours.
Presumably, the abilities of the other base spirits aren't much different, and some might even have a more outrageous effect than vodka.
If that's the case, it would be normal to use it only once per game. Otherwise, if vodka was used on everyone, other players would be out for good.