Oak-barrel aging

Tequila is usuaky bottled at 80—86° proof. It is sold unaged as white tequila or it can be matured in oak barrels. Aging gives Tequila a golden color and a pleasant mekowness without altering its basic taste. 

FIGURE 5.12 Levels of (A) 2,2,6-trimethylcyclohexanone and (B) p-ionone in ruby port wine and oak barrels aged port wines. 

C.4 Changes in the Wine Volatile Composition During Oak-Barrel Aging.303... 

The two oak lactone isomers cis- and fran -p-methyl-y-octalactone) were first identified in oak wood by Masuda and Nishimura (1971). They are one of the main volatile components present in the extractible fraction of oak wood. Smdies have revealed the detection thresholds for these two isomers to be 0.092mg/L for the cis isomer and 0.49mg/L for the trans isomer in white wines (Chatonnet 1991). Their aroma has been identified as the source of the typical odour of oak barrel aging and has been described as oak or coconut . 

Wine treated with oak chips matures quickly, and more phenolic compounds can be extracted from wood chips than from oak staves and oak barrel aging (Alamo-Sanza etal. 2004). 

Handle oak barrel aging properly (disinfection, toppings, rackings, cellar temperature)... 

The clarification methods of fining and filtration also act to stabilize wine by removing some of the same particles that can promote instability. The subtle oxidation that occurs with oak barrel aging has a naturally stabilizing effect on the wine. 

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. 

The grain whiskeys used in Scotch blends are produced using com, rye, and barley malt and are distilled using a continuous multicolumn stiU at 180—186° proof (90—93%). Grain whiskeys are aged in used oak barrels of 190 Hter capacities. The used barrels are often purchased in the United States from bourbon distilleries. 

Gra.in Spirits. Grain spirits are neutral spirits from grain that are matured in used oak barrels and bottled at 80° proof or higher. The period of aging in oak may be declared on the botde. 

In the United States about 95% of the brandy comes from California. The first brandy was made in 1837 though it was not produced in quantity until 1867. Ak California brandy must be made from grapes grown and distiked in the state and aged a minimum of two years in oak barrels. 

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... 

Benzoic aldehydes mainly cover syringaldehyde and vanillin. Natural vanilla is prepared from the seeds (beans) of Vanilla planifolia, which may contain about 21 mg/ 100 g FW total phenols, including the major components vanillin (19.4 mg/100 g FW), 4-hydroxybenzaldehyde (1 mg/100 g FW), and vanillic acid (0.4 mg/100 g FW) (Clifford 2000b). In mango, vanillin has been found as free as well as vanillyl glu-coside (Sakho and others 1997). It has also been found in lychees (Ong and Acree 1998) and wines (Moreno and others 2007). For analysis of both brandy and wine aged in oak barrels, the limits of detection were found to be 27.5, 14.25, 14.75, and... 

RELATIVE AMOUNT OF EIGHT ANTHOCYANINS IN FOUR TEMPRANILLO WINES (VINTAGE 1999) DURING THEIR AGEING IN OAK BARRELS (O) OR IN STAINLESS STEEL TANKS (S)... 

Apetrei, C., Apetrei, 1. M., Nevares, L, Del Alamo, M., Parra, V., Rodriguez-Mendez, M. L., and De Saja, J. A. (2007). Using an e-tongue based on voltammetric electrodes to discriminate among red wines aged in oak barrels or aged using alternative methods. Electrochhn. Acta 52(7), 2588-2594. 

Parra, V., Arrieta, A. A., Fernandez-Escudero, J. A., Iniguez, M., De Saja, J. A., and Rodriguez-Mendez, M. L. (2006a). Monitoring of the ageing of red wines in oak barrels by means of an hybrid electronic tongue. Anal. Chim. Acta 563(1-2), 229-237. 

Ortega-Heras, M., Rivero-Perez, M. D., Perez-Magarino, S., Gonzalez-Huerta, C., and Gon-zalez-Sanjose, M. L. (2008). Changes in the volatile composition of red wines during aging in oak barrels due to microoxygenation treatment applied before malolactic fermentation. 

New enological technologies aim to lower volatile acidity, enhance sugar content in must in cool climates and vice versa reduce the alcohol content of wines from hot climates, modify pH, cations, anions and acidity to achieve tartrate stability, complement traditional ageing in oak barrels with the use of small oak wood particles and most recently, extract phenolic compounds by a countercurrent chromatography process from wine to diminish or enrich tannins in red wines. 

Marti, M.R, Pino, J., Boque, R., Busto, O., Guasch, J. (2005) Determination of aging time of spirits in oak barrels i ing a headspace-mass spectrometry (HS-MS) electronic nose system and multivariate calibration. In Analytical and Bioanalytical Chemistry 382 (2) The European Conference on Analytical Chemistry XIII, pp 440-443. 

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