Why does Troy always spill Gin before drinking?

I'm sorry, I see no evidence in the text as to the question you're asking. Act and scene please?

in my country, the old folks believe that you have to give back a little to Mother Earth. So everytime they open a bottle of gin they spill a little before drinking. This is also done if they have their meals outside (in the farm or in a picnic) they throw a little food to mother earth before eating.

i guess Troy's habit is a manifestation of the same belief.