Scientists at Brown University Center for Alcohol and Addiction Studies in Providence, Rhode Island, and the University of Michigan Medical School have determined that alcohols containing more congeners produce worse hangover symptoms than alcohols containing fewer congeners. Congeners are complex organic molecules that result from the fermentation or aging process and produce the characteristic flavors and aromas of specific types of alcohol. Examples of congeners are acetone, acetaldehyde, and tannins. One way of gauging the concentration of congeners in an alcoholic beverage is by its color. Pale spirits contain fewer congeners than darker spirits, so you can expect a hangover from the same dose of a lighter-colored alcohol may be less severe than a hangover from a deeply-colored alcohol.
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