Charred barrels

It has been shown that aromatic aldehydes including vanillin, syfingaldehyde, coniferaldehyde, siaapaldehyde, and ethyl lignin come from charred wood, the length of matufing directly affects the amount of aldehydes formed, the lower proof spirits have more aldehydes than higher proof spirits do, and the used and new uncharred barrels produce about one-third of the aromatic aldehydes found ia new charred barrels (Table 3) (8). 

A study of the effect on the congener levels of up to eight refills of a used whiskey barrel iadicate that volatile acids, esters, colors, soHds, and tannins showed the greatest percentage change between the first and second use of a new charred barrel (11). 

Once the desired conditions have been reached and the planned process rate established, the system can be operated in a steady-state mode. This may take four or five hours from a cold start or two to three in a run where hot char from the previous days operation is in the convertor. During the steady mode operation, feed is added about every 30 minutes, the char grate opened for a few seconds 30 to 9-0 times each hour and the char drums changed every hour. Two char barrels equipped with quick disconnect hardware are used for rapid replacement of the drums. To prevent burning, the char is stored in sealed barrels while it cools. The oil is periodically gathered from the condenser and demister. Typically, the condenser recovers about three quarters of the total oil while the demister recovers the remainder. 

Aging practices differ somewhat. British custom is to store the whiskey in uncharred oak barrels while American whiskies, both Rye and Bourbon, are stored in charred barrels. The color and solids of whiskey aged in uncharred packages are much smaller in amount and more water soluble than those of whiskey stored in charred packages. The charring also results in a bead of oilier consistency and greater permanence than the uncharred barrel imparts. 

White oak barrels of 190 liters (50 U.S. gallons) that have been previously used for bourbon maturation are often used a second and third time to age Canadian whisky. This used cooperage along with the higher proof distillation gives Canadians their characteristic light flavor compared to the heavy flavor of most bourbons aged in new charred oak barrels. 

Whiskey. Whiskey refers to any alcohohc distiUate made from a fermented grain mash at less than 190° proof (95%) in such a manner that it possesses the taste, aroma, and characteristics generaUy attributed to whiskey. It is matured in new or used charred oak barrels. Whiskey can be further delineated by the cereal grains used and the maturation time and blending, if any. 

Bourbon. Bourbon, and also rye, wheat, malt, and rye malt whiskeys, are made from a fermented mash not less than 51% com, rye, wheat, malt, or rye malt, respectively. They are distiUed at not over 160° proof and matured at not more than 125° proof in new charred oak barrels and bottled at not less than 80° proof. If stored for less than four years, it must be declared on the label. 

Brandies are distiked using batch or continuous systems. Variations of the pot stik are used in France. Elsewhere, both systems are used. The batch system yields a more flavorful product, whereas the continuous stik yields a lighter flavor. The first distikate using a pot stik is taken off at 60° proof. It is then redistiked to 148—160° proof. Brandy is matured in charred-oak barrels for two to eight years and bottled at 80° proof or higher. 

Much work has been reported and summarized ia the Hterature on the matufing of various whiskeys ia charred or uncharred white-oak barrels (4—7). The early Hterature iadicates that total acids, aldehydes, esters, soHds, and color iacreased with aging time and that their concentrations were iaversely proportional to proof. Thus aging at higher proofs (over 127°) yields less color and flavor. The maximum allowable entry proof for straight whiskeys was iacreased from 110° to 125° by the U.S. Treasury Department ia 1962. 

In the US, more than 80% of caramel is used to color drinks such as colas and beers. Another important application is the coloring of blended whiskeys produced by mixing straight whiskeys with neutral spirits. The addition of neutral spirits to the straight whiskey produces a loss of color that can be compensated by the addition of caramel. Straight whiskeys are colored during aging for 2 yr in freshly charred oak barrels and contain furfural and 5-HMF in a ratio of 2 to 2.6 1, while the ratio... 

Whiskeys Grains brewed with water to form a beer of 5%-10% alcohol. Beer is distilled and aged in new or used charred oak barrels for two to eight years before blending. 40-50... 

Whisk(e)y flavor. The typical W. flavor develops on maturation in charred (toasted) wooden barrels (Bourbon) or old sherry barrels (Scotch). Components relevant for the sensory impression are the fusel alcohols (ca. 2000-4000 ppm) and their acetates, ethyl acetate (see fruit esters), and the ethyl esters of saturated and unsaturated fatty acids, acetaldehyde, 3-methylbutanal... 

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