I thought it was pretty cut and dried. I was wrong. You put alcohol in a pan, you cook it for a while and all the alcohol evaporates, easy…aah no not really! So I started browsing through the internet to see what it says. Some cook sites cautions that a dish with wine must be cooked long enough to remove the harshness of the alcohol. In fact, some sites wanted you to simmer and reduce the wine separately from the sauce, and add it only when it has been gently reduced to its essence. Quite a few sites just do not say how long this might take?
In general, the main reason any alcoholic beverage is used in a recipe is to impart flavour. After all, the finest extracts with the most intense flavours are alcohol-based, particularly vanilla. Fermentation intensifies and concentrates fruit essence into liqueurs, cordials, brandies and wines. Many people object to the alcohol content, but it is a completely natural by-product which happens daily in nature, even within the human body. In many recipes, the alcohol is an essential component to achieve a desired chemical reaction in a dish.
They say you need to cook a sauce for at least 20 to 30 seconds after adding wine to it to allow the alcohol to evaporate. And there is some sense to that, since alcohol evaporates at 172°F (78°C), so any sauce or stew that is simmering or boiling is certainly hot enough to evaporate the alcohol. If you think about when we flambéed foods, it often takes at least a minute for the flames to die out, a sign to many of us that most of the alcohol is gone.
How much alcohol remains in the dish depends on the cooking method and amount of cooking time. Those bourbon-soaked fruitcakes would have to turn into bricks before the alcohol evaporates. A pint of Guinness in a long-simmered stew is not going to leave a significantly measurable alcohol residue, but will add a rich, robust flavour. A quick flambé may not burn off all the alcohol, whereas a wine reduction sauce will leave little if any alcohol content. Heat and time are the keys. Obviously, uncooked foods with alcohol will retain the most alcohol. Now, it may be that the amount of alcohol in a dish is modest to start with, but the fact that some of the alcohol remains could be of significant concern to recovering alcoholics, parents, and others who have ethical or religious reasons for avoiding alcohol.
The following chart data I found comes from the U.S. Department of Agriculture with information on how much alcohol remains in your food with specific cooking methods. Keep in mind that this is the percentage of alcohol remaining of the original addition. Now you know for next time you add the alcohol to the dish.

Alcohol Burn-off Chart
alcohol added to boiling liquid & removed from heat 85%
alcohol flamed 75%
no heat, stored overnight 70%
baked, 25 minutes, alcohol not stirred into mixture 45%
Baked/simmered dishes with alcohol stirred into mixture:
15 minutes cooking time 40%
30 minutes cooking time 35%
1 hour cooking time 25%
1.5 hours cooking time 20%
2 hours cooking time 10%
2.5 hours cooking time 5%

Happy Drinking
By Nikki Schaafsma-Harris
Oak Barrel Wine Boutique