Contrary to what most people believe, and that includes most professionals, when using beer, wine or other alcoholic beverages in recipes, a lot of alcohol is left after cooking.
Here are the facts from the Agricultural Research Service of the USDA (1989).
ALCOHOL IN COOKING
Alcohol remaining after preparation:
100 percent Immediate consumption
70 percent Overnight storage
85 percent Boiling liquid, remove from heat
75 percent Flamed
Baked or simmered:
40 percent after 15 min
35 percent after 30 min
25 percent after 1 hour
20 percent after 1.5 hour
10 percent after 2 hours
5 percent after 2 1/2 hours