THIRD EDITION Concepts IN Wine Chemistry YAIR MARGALIT, Ph.D. The Wine Appreciation Guild San Francisco Contents Introduction ix I. Must and Wine Composition 1 A. General Background 3 B. Sugars 5 C. Acids 11 D. Alcohols 22 E. Aldehydes and Ketones 30 F. Esters 32 G. Nitrogen Compounds 34 H. Phenols 43 I. Inorganic Constituents 52 References 55 n. Fermentation 61 A. General View 63 B. Chemistry of Fermentation 64 C. Factors Affecting Fermentation 68 D. Stuck Fermentation 77 E. Heat of Fermentation 84 F. Malolactic Fermentation 89 G. Carbonic Maceration 98 References 99 v III. Phenolic Compounds 105 A. Wine Phenolic Background 107 B. Tannins 120 C. Red Wine Color 123 D. Extraction of Phenolic Compounds from Grapes 139 References 143 IV. Aroma and Flavor 149 A. Taste 151 B. Floral Aroma 179 C. Vegetative Aroma 189 D. Fruity Aroma 194 E. Bitterness and Astringency 195 F. Specific Flavors 201 References 214 V. Oxidation and Wine Aging 223 A. General Aspects of Wine Oxidation 225 B. Phenolic Oxidation 227 C. Browning of White Wines 232 D. Wine Aging 238 References 253 VI. Oak Products 257 A. Cooperage 259 B. Barrel Aging 274 C. Cork 291 References 305 vi VH. Sulfur Dioxide 313 A. Sulfur-Dioxide as Food Products Preservative 315 B. Sulfur-Dioxide Uses in Wine 326 References 337 Vm. Cellar Processes 341 A. Fining 343 B. Stabilization 352 C. Acidity Adjustment 364 D. Wine Preservatives 372 References 382 IX. Wine Faults 387 A. Chemical Faults 389 B. Microbiological Faults 395 C. Summary ofFaults 402 References 409 X. Wine and Health 413 A. General View 415 B. Biogenic Amines 421 C. Red Wine Headache 423 D. Ethyl-Carbamate 424 E. Lead in Wine 427 F. Dealcoholized Wine 431 G. Organic Wines 433 References 457 vii XI. Legal Aspects 445 A. Wine Laws 447 B. Wine Additives 455 C. Wine and Driving 458 References XH. Wine Chemistry of "Old Times" 459 A. General Concepts of Wine 461 B. Fermentation and Winemaking Practice 463 C. Chemistry and Wine Quality 474 D. Aroma and Flavor 479 E. Wine Faults.. 482 F. Fraud, Illegal Matters, and "Special Techniques" 488 G. Wine Critics 494 H. Wine and Medicine 497 I. Taxes, Politics, Law and Trade 501 J. Wine and Food, Culture and Society 504 References 509 Epilogue Index viii.