Funny you mention alcohol. I was at a family gathering last month, and the grilled burgers were huge and delicious. I make burgers all the time, adding turkey bacon to the mix, and mine are pretty damn good, but these were better. So I asked the guy who made them what his secret was. He said lots of red wine in the burger mix. I didn’t taste any wine.
But of course I went home and tried to recreate. Fail. My burgers tasted like wine. No one really liked them. Maybe he just sprinkled the wine over while they were on the grill, I don’t know. I gave up with the wine.
It looks like the secret may lie in using a wine reduction:
http://www.thebrewerandthebaker.com/archives/1196
Looks to me like the burger maker hinted at using spice mix in addition to the vino....but apparently did not care to share his secret spice mix.