I recommend staying away from alcohol for the first year post surgery. Your liver is working hard while you are in your weight loss phase, and shouldn't have to deal with the extra stress of processing alcohol.
When you are stabilized and do have a beverage or two, like Sue, most of us feel the effects pretty quickly, yet the effect dissipates just as quickly. I couldn't say what the medical readings are with blood alcohol, so I wouldn't want to test being the designated driver even if I felt stone cold sober. Drinking alcohol can also dehydrate, so take it easy and drink lots of water.