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Food 101

Cooking With Wine
By Robert L. Wolke

Wednesday, September 29, 2004; Page F01

True or false? Cooking with wine adds extra flavor to a dish because the
alcohol dissolves flavor components that are not dissolvable in water.

This statement, or statements like it, have been repeated in several places.
Chefs I've spoken with accept it as quite reasonable and indeed it does seem
to make sense, because many substances do dissolve in alcohol, but not in
water.

Nevertheless, the statement is false. The real reason we use wine in cooking
is simply that a good wine contributes its good flavor to the dish. It has
nothing to do with dissolving flavor components.

Here's the catch: In a mixture of alcohol and water such as wine, the
alcohol doesn't act like pure alcohol and the water doesn't act like pure
water. They act like a mixture of alcohol and water, and a mixture can have
quite different properties from either of the pure liquids.

If we mix equal amounts of alcohol and water, the mixture will be more than
2½ times as viscous ("thick") as either the pure alcohol or the pure water.
The reason is that alcohol molecules and water molecules attract and stick
to each other by forming so-called hydrogen bonds. They cannot flow as
freely as the unhindered molecules can in pure alcohol or pure water. The
properties of the mixture, including what it can and cannot dissolve, vary
as the percentage of alcohol varies. If a given substance dissolves in pure
alcohol or pure water, that doesn't mean it will dissolve in any given
mixture of alcohol and water.

On Solvents, Solutes and Solvation

The following two paragraphs are for technically inclined readers. Scan,
skim or skip them as your disposition dictates.

For a liquid such as alcohol (a solvent) to dissolve a soluble substance (a
solute), the solvent's molecules must surround (or solvate) each solute
molecule like a swarm of hungry piranhas and drag it out into the liquid.
But if the alcohol is mixed with water, the hydrogen bonds between them
hamper the alcohol molecules' ability to solvate the molecules of the
solute. Thus, a mixture of alcohol in water cannot effectively dissolve what
pure alcohol might be able to dissolve.

Moreover, the less alcohol there is in the water, the more its solvent
abilities are weakened. For example, when you add half a cup of wine
containing 12 percent alcohol to a quart of braising liquid, the alcohol
concentration is reduced to 1.5 percent. The alcohol molecules are
outnumbered by water molecules by nearly 200 to 1, so there aren't enough of
them to solvate the solute molecules.

The Experiment

Is all of this mere theory? No. I did an experiment to test it.

Annatto seeds, also known as achiote (ah-chee-OH-tay), are the seeds of the
tropical evergreen shrub Bixa orellana. They are coated with a paste-like
oil containing an intense yellow-orange carotenoid pigment called bixin,
which dissolves in oils and in alcohol but not in water. Annatto's bixin is
an FDA-approved coloring for fatty foods such as butter, margarine and
processed cheeses. In this experiment, I used the highly visible bixin to
simulate an alcohol-soluble flavor component in a food.

I placed five annatto seeds into each of four small test tubes and added 15
milliliters (a tablespoon) of one of the following liquids to each tube:
water, a chardonnay containing 13 percent alcohol, a vodka containing 40
percent alcohol (80 proof), and 95-percent-pure ethyl alcohol. I let the
tubes stand at room temperature for several days, with occasional shaking.

Here are the results: Neither the water nor the wine showed any bixin color
at all; the water remained colorless and the white wine remained, well,
white-wine-colored. The vodka turned mildly yellow from a small amount of
dissolved bixin, while the 95-percent-pure alcohol turned intensely yellow.

Conclusion: Wine -- even straight, undiluted wine -- doesn't dissolve or
"release" any alcohol-soluble bixin from the seeds. The alcohol
concentration has to be high, some 40 percent or higher, to extract any
appreciable amount of bixin. But such high alcohol concentrations never
occur in cooking. Adding half a cup of vodka to a quart of sauce would
produce a solution of only about 5 percent alcohol, even lower than the
completely ineffective alcohol concentration in undiluted wine.

Now We're Cooking

But that was at room temperature. What happens in the heat of cooking?

Although most substances are more soluble at higher temperatures, the facts
of life regarding hydrogen bonding are still in effect. So while hot, pure
alcohol will extract more alcohol-soluble components at higher temperatures,
hot wine still won't.

Nevertheless, the alcohol in wine can contribute to flavor beyond the
flavors inherent in the wine itself. During cooking, the alcohol can react
chemically with acids in the food to form fragrant, fruity compounds called
esters. You can demonstrate this by vigorously shaking some denatured
alcohol with vinegar (acetic acid) in a tightly sealed bottle. After shaking
for a few minutes, open the bottle carefully and sniff; in addition to the
odors of the alcohol and vinegar, you will detect a fruity note of ethyl
acetate, one of the esters in the aroma of pineapple.

In the cooking pot, alcohol also can react with any oxidizing substance to
form aldehydes -- compounds responsible for flavors such as almond, cinnamon
and vanilla. Both the esters and aldehydes are new flavors that were not
present in the original ingredients. And, contrary to widespread belief, the
alcohol never "boils off" completely. It has plenty of time to take part in
these chemical reactions during cooking. That's another virtue of cooking
with wine.

So enjoy your coq au vin and boeuf Bourguignonne. The wine will add flavor
in several ways but don't expect it to "extract" or "release" any
alcohol-soluble flavors from your food.

Now that I think of it, why must we extract flavor compounds from our food,
anyway? If they're in there, they're in there, and we'll taste them when we
chew, whether they inhabit the solids or the sauces.

Robert L. Wolke (www.professor science.com) is professor emeritus of
chemistry at the University of Pittsburgh and the author, most recently, of
"What Einstein Told His Cook: Kitchen Science Explained" (W.W. Norton). He
can be reached at .