This is a subject that needs to be addressed. Often, I have candidate's ask me what the standard protocol is on consuming alcohol during an interview. My answer is always the same. Water with a lemon please. Seriously! You are meeting with the hiring manager for a reason – to interview for a job – period. Once inside the eating establishment you can quickly become engaged in a great conversation.
Have an innocent glass of wine or a drink - then another (Please not a third libation). All of the sudden your words are slurring, you are throwing your current employer under the bus and the wheels are suddenly coming off. You've let your hair (and your guard) down. You may have forgotten the person’s name across the table from you and who knows what other thoughts might come out of your brain and eventually out of your mouth. This is a recipe for a real disaster. Some people are just wired that way. Two drinks (wine, beer or liquor) and it's (well) game over. Not good.
Let’s not forget why you are meeting - to interview for a new position and put your best foot forward to advance the search to an offer and a hopefully a new job. You are not there to see how fast you can down 2-3 shooters before the appetizers are served. The person on the other side of the table will be judging every move you make to see how well you handle yourself in a social situation. They may encourage you ordering a drink – just to see how you respond. This includes your consumption of alcohol and overall etiquette during dinner. Do yourself a (very) big favor, stay away from the booze. Period. If your host insists and really pushes the issue to share a drink before dinner - order ONLY one. That means a single glass of wine or a cocktail out of politeness and NURSE IT ALL NIGHT with a side glass of water (with or without the lemon). No Exceptions.
You are there to prove you are the best person for the job - not to showcase your drinking skills. You want to be remembered as the professional that met the hiring manager for dinner, had a nice conversation and an enjoyable meal. Hopefully your performance will yield an offer the next day or so after showcasing your social skills.
Take the high road every time when it comes to alcohol during any important meeting and you will come out on the right side of the equation. Take the low road and well... you might be calling a cab starting over from scratch on your job search after you sleep off your headache.