蒸餾法[[酒]]

Distillation history
Beer and wine were historically limited to a maximum alcohol content of about 15% by volume, beyond which yeast is adversely affected and cannot ferment. Alcohol levels higher than 15 percent have historically been obtained in a number of ways.

The first evidence of true distillation comes from Babylonia and dates from the fourth millennium BC. Specially shaped clay pots were used to extract small amounts of distilled alcohol through natural cooling for use in perfumes, however it is unlikely this device ever played a meaningful role in the history of the development of the still. By the 3rd century AD there is evidence that alchemists in Alexandria, Egypt, used distillation to produce alcohol for sublimation and for colouring metal.

Freeze distillation or the "Mongolian still", is known to have been in use in Central Asia as early as the 7th century AD. This method involves freezing the alcoholic beverage and removing water crystals. The freezing method had limitations in geography and implementation and thus did not have widespread use, but remained in limited use, for example during the American colonial period applejack was made from cider using this method.

Distilled alcohol first appeared in Europe in the mid 12th century among alchemists, who were more interested in medical "elixirs" than making gold from lead. It first appears under the name aqua ardens (burning water) in the Compendium Salerni from the medical school at Salerno. The recipe was written in code, suggesting it was kept a secret. Taddeo Alderotti in his Consilia medicinalis referred to the "serpente" which is believed to have been the coiled tube of a still.

Modern distillation
The actual process of distillation itself has not changed since the 8th century. There have, however, been many changes in both the methods by which organic material is prepared for the still and in the ways the distilled beverage is finished and marketed. Knowledge of the principles of sanitation and access to standardised yeast strains have improved the quality of the base ingredient; larger, more efficient stills produce more product per square foot and reduce waste; ingredients such as corn, rice, and potatoes have been called into service as inexpensive replacements for traditional grains and fruit. Chemists have discovered the scientific principles behind aging, and have devised ways in which aging can be accelerated without introducing harsh flavours. Modern filters have allowed distillers to remove unwanted residue and produce smoother finished products. Most of all, marketing has developed a worldwide market for distilled beverages among populations which in earlier times did not drink spirits.


Chemical profile
A distilled beverage is typically manufactured by distillation, aging if applicable and dilution to the set percentage of alcohol.

Distillation is done at least twice, due to the chemistry involved. Copper is typically used as a chemically near-inert metal for the equipment. However, it is still very much a transition metal catalyst, and catalyses the formation of poisonous and harmful by-products, such as urethane. Removal of these is necessary and warrants a second distillation step.

After distillation, the alcohol may be aged in traditional oak casks. Whiskey, for example, is aged at 77%. Dilution is done to attain the standard percentage, from 30 to 80%. The (arbitrary) percentage of 40% is the most common "standard". However, a lower percentages such as 38% may make the drink more palatable. Also people often mix water into the drink to suit their tastes.

The final drink contains water, alcohol, fusel oils, and flavouring compounds. In some cases, additional sugar is added. Fusel alcohols are higher alcohols than ethanol, are mildly toxic, and have a strong, disagreeable smell and taste.