TY - JOUR T1 - The Changes in Certain Components of Setubal Wines During Aging JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 146 LP - 150 DO - 10.5344/ajev.1984.35.3.146 VL - 35 IS - 3 AU - Domingos Soares Franco AU - Vernon L. Singleton Y1 - 1984/01/01 UR - http://www.ajevonline.org/content/35/3/146.abstract N2 - The total phenols, nonflavonoids, extract, sugar, fixed acidity, volatile acidity, and absorbance characteristics were analyzed in 24 muscatel wines ranging in age in barrels from 0 to 77 years. The apparent nonflavonoid phenol content increased with age fairly regularly from 150 mg/L to 1100 mg/L gallic acid equivalent owing to wood extraction and evaporation. Extract and sugars increased regularly approximately four-fold owing to evaporative losses. Volatile acidity increased regularly also, but all other values indicated a winemaking difference in the older wines. Fixed acidity increased approximately two and a half times, less presumably owing to the precipitation Of potassium bitartrate and esterification. Flavonoid content was higher among wines of 1923 and earlier than from 1927 and later, indicating a processing difference such as greater pomace contact. Extraction and concentration of phenols gave rise to a large and proportional increase in the absorbance peak near 280 nm. Oxidation of phenols to yellow and brown pigments led to even larger progressive increases in absorbance beyond 400 nm with wine age and was apparently associated with flavonoid content. Some comments on flavor characteristics are given. ER -