Does Alcohol Cook Off Entirely?

Sometimes I like America's Test Kitchen, sometimes I don't. I find the recipes can be a bit fussy for my taste, despite my rather fussy tastes. That said, there are usually a few tidbits of information that I enjoy having learned. Mmm...culinary nerd.

Case in point: America's Test Kitchen From Cook's Illustrated: "French Classics"

Does cooking remove all of the alcohol (e.g., beer or wine) in a dish? I've always wondered this, and I'd decided that the answer was "no." That said, I have nothing on which to base my conclusion. I'm just being conservative. I am a true believer in the flavor enhancing benefits of alcohol in food, so I won't stop cooking with it. A little white wine in a rather bland beef stew can make it sing. And MetaDaddy's chicken breasts, onions, and tomatoes cooked in a bit of vermouth makes me dance to the table every time.

But America's Test Kitchen has finally answered the question I had always pondered. And here's what they had to say:

When you add alcohol to a dish, it can't all burn off because alcohol and water, which are very fond of each other, form an azeotropic mixture.

Professor Guy Crosby: "This is a mixture that you get when you have two different molecules that mix together that have a very high affinity for each other. And so they basically behave as though they're almost a single compound."

In other words, the vapor that evaporates is a mixture of water and alcohol.

"When the alcohol and the water mixture in the pot begin to simmer, the liquid is actually beginning to boil at a temperature quite a bit below the boiling point of water. It's actually just a little bit above the boiling point of alcohol. Alcohol is about 170 degrees fahrenheit, whereas this mixture will start to evaporate at about 175 degrees fahrenheit. And the first vapors that come off the pot will be very high in alcohol. And as more alcohol is removed, the amount of water in the vapor, and as a result the temperature of the simmering liquid in the pot continues to rise until towards the very end. The vapor will be around 95% water and 5% alcohol and it will be boiling at just a little below the boiling point of water. But you'll always have that mixture of about at least 5% alcohol remaining in the pot."

But wait, there's more!

Does it matter if you cook with the lid on or off? Here's what their tests showed.

Lid On
Type of Stew - Beef
Time - 3 hours
Alcohol Reduction - 60%

Lid Off, Wider Pot
Type of Stew - Chicken
Time - 28 minutes
Alcohol Reduction - 90%

Resulting Theory
You can remove the majority of the alcohol from a dish if you simmer using a wide, uncovered pot. The wider the pot or skillet, the faster the alcohol evaporates. In fact, you'd see a significant different in using a 12 inch versus 10 inch skillet.

Nifty, huh?

Another interesting bit of info is in how the liquid is reduced in a broth with alcohol.

Reduction #1: Reduced 2 cups of wine to 1/2 cup, added 2 cups of broth, and reduced everything to a final volume of 1 cup.

Reduction #2: Combined 2 cups of wine and 2 cups of broth and then reduced the mixture to 1 cup.

Results
The resulting broths were quite different. #1 had a "smooth, clean flavor" and #2 was "overshadowed by booziness." So if you want cut corners while cooking, don't do it by failing to fully reduce your alcohol before adding other liquids.

Bon appetit!