Distillation Flashcards
Distillation
in which a fermented brine, broth or juice is run through a Still, a device that uses heat and cooling to extract a liquid with a certain percent of alcohol.
A distilled beverage, liquor, or spirit
a drinkable liquid containing ethanol that is produced by means of distilling fermented grain, fruit, or vegetables. This excludes undistilled fermented beverages such as beer and wine.
Spirit
a distilled beverage that contains no added sugar and has at least 30% ABV.
Popular spirits
Absinthe, baijiu, brandy, eau-de-vie, gin, grappa, rum, tequila, vodka, and whisk(e)y.
Liqueurs
Distilled beverages that are bottled with added sugar and added flavorings, such as Grand Marnier, Frangelico, and American schnapps,
Fortified Wine
Created by adding a distilled beverage (usually brandy) to a wine.
A distilled beverage
typically manufactured by distillation, aging if applicable, and dilution to the set percentage of ethanol. Distillation is done at least twice, due to the chemistry involved; Ethyl alcohol evaporates at a lower temperature than water, but not completely in one step. This makes it possible to increase the ratio of ethyl alcohol to water with repetition. Copper is typically used as a chemically near-inert metal for the equipment. However, it is still very much a transition metal catalyst, and catalyzes the formation of poisonous and harmful by-products, such as urethane. Removal of these is necessary and warrants a second distillation step. Most “colored” alcohols are distilled in a batch process, but continuous processes are found in the production of flavorless vodka and similar drinks. 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, ethanol, fusel oils, and flavoring compounds. In some cases, sugar is added. Fusel alcohols are higher alcohols than ethanol, are mildly toxic, and have a strong, disagreeable smell and taste. Fusels in moderate quantities are considered to be essential parts of the taste profile of flavored drinks such as whiskey and cognac. In drinks intended to be relatively flavorless (such as vodka), they are defects. Incompetently distilled drinks also contain distillation heads, which are poisonous in large amounts and consist mostly of methanol and foul-smelling byproducts of fermentation.
Distillation
The extraction of alcohol from a low strength alcoholic liquid to make it into a stronger one. The Cognacais in France do it with wine, the Tequileros of Mexico do it with pulque, a beverage made by fermenting the juices of the agave plant and the vodka distillers do it with a liquid called wash, made by fermenting a mixture of grain or other crops with water.
The grain (or potatoes, agave, etc.) are first crushed and mixed with water. In this case, we’ll talk about vodka. The grain is made into a mash. They are then heated up to convert their starch into sugar. When yeast is added this ferments and produces a wash with an alcoholic strength of 6-8 percent. Distillation then converts this into what is known as raw spirit.
Vodka was first distilled in what we know today as pot stills. Pot stills are still widely in use in production of Brandy and both Scotch Irish whisk(e)ys. They look like huge copper cauldrons which are closed at the top into a V-shaped funnel.
The wash is heated inside them and as the heat rises, the wash begins to release its vapors. Since the alcohol boils at a lower temperature then water, 172°F for alcohol and 212°F for water, it seems to be very easy to extract alcohol from a liquid. In practice its far from easy, since water vaporizes at every temperature so by the time the wash is heated to 172°F a lot of steam is mixed with vaporized alcohol.
The process consists in capturing the part of the vapor that is highest in alcohol content and then distill it again.
The first part of the distillation, called the head, tends to contain a considerable amount of impurities and the last part, called the tail, contains a lot of water vapor. The distiller therefore keeps only the middle part of the distillation, the heart, and keeps distilling the heart up to four times depending on the character of the final product he wishes to achieve. Every time he distills the middle part from a previous distillation process, he keeps only the heart for further distillations reaching finally a raw spirit with an alcohol level of 120 proof. The spirit is then diluted with water to about 80 proof in most cases.
Pot stills are still used in vodka production since they give a spirit with higher smoothness, but most vodkas are produced in what we know as continuous, patent or Coffey stills, which are considerably more efficient. They enable the distiller separate all the ingredients in the vodka wash in one process thus creating a final product in one take.
