Alcohol is the substance that gives spirits, wine and beer their effect. In the bar, we almost always mean ethanol, chemically C₂H₅OH. It is produced by fermentation or distilled to achieve higher concentrations. Without alcohol, there would be no classic bar culture.
What alcohol is chemically
Ethanol belongs to the family of alcohols, a group of organic compounds with a hydroxyl group. In nature, it is produced when yeasts metabolize sugar, creating ethanol and carbon dioxide. This process is called alcoholic fermentation and is the basis for beer, wine and sake. The concentration usually stays below 15 percent by volume because higher levels kill the yeasts. Distillation separates the alcohol from the water and concentrates it to 40 to 96 percent by volume, depending on the product. In this form, it ends up in vodka, gin, rum and all other spirits.
How alcohol works in the bar
Alcohol is not just an intoxicant, but also a solvent and flavor carrier. Many aromas from herbs, spices or fruits dissolve better in alcohol than in water. This is why infusions and macerations work so well. Alcohol also influences the texture of a drink: it feels warmer than water, burns slightly on the tongue and enhances the perception of bitterness. In high concentrations, it acts as a preservative, which is why spirits are practically indefinitely shelf-stable. In cocktails, the alcohol is balanced with acid, sweetness and dilution so that it does not dominate but supports the overall picture.
Alcohol content and ABV
The alcohol content is given in percent by volume, often abbreviated as ABV (Alcohol by Volume). A gin with 40% ABV consists of 40 percent pure ethanol, the rest is mostly water. In the USA, you may still find the term Proof, which is twice as high as the ABV: 80 Proof corresponds to 40% ABV. For bar work, the ABV is crucial because it determines how strong a drink will be. A Martini made with high-proof gin and vermouth remains alcoholic, while a Sour made with juice and syrup is much milder. To calculate the final ABV of a cocktail, you need to add the alcohol content of all ingredients and divide by the total volume.
Common misconceptions
Many people believe that alcohol evaporates completely when flambéed or cooked. This is not true: even after prolonged heating, some remains. Another misconception is that clear spirits contain less alcohol than dark ones. The color does not indicate the ABV; a white rum can be just as strong as a dark one. Some also think that alcohol warms the body. In reality, it dilates the blood vessels and creates a temporary sensation of warmth, but the body cools down more quickly as a result. In the bar, you should also know that alcohol is not broken down by coffee, cold showers or fresh air. Only the liver can do that, at a rate of about 0.1 per mille per hour.
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Frequently asked questions
Can you taste the alcohol content of a drink?
Experienced bartenders and guests can often recognize high alcohol concentrations by the burning sensation on the tongue and the warmth in the mouth. The ABV can only be measured precisely with a hydrometer or by calculation.
Why do some spirits have 40 percent, others 50 or more?
The ABV depends on distillation, dilution and tradition. Many spirits are set at 40 percent because this was tax-advantageous and balanced in flavor. Navy Strength gin has 57 percent because this concentration was considered fireproof on ships.
Are there differences between alcohol from grain, grapes or sugarcane?
Chemically, ethanol is always the same, no matter the source. In terms of flavor, however, different raw materials bring along compounds that remain as aromas after distillation. A Cognac made from grapes tastes different from a rum made from molasses, even though both contain ethanol.
Does an open drink lose alcohol?
Alcohol evaporates more slowly than water, but in an open glass over hours, some is indeed lost. In practice, the effect is minimal as long as the drink is consumed in a timely manner.
