winephacidity(编辑修改稿)

winephacidity(编辑修改稿)内容摘要：

n of base, OH reacts with H+ to produce water: OH + H+  H2O  Limited change in pH will occur, due to these interactions  In each case, the original equilibrium will be reestablished at the new pH based on Ka values Wine Acidity Titration Curve  Weak acid vs. Strong Base, therefore endpoint is pH 7  Flat areas of curve show areas of greatest buffer capacity  Although wine is a mixture of weak acids, it is not possible to separate them by titration as the pKa values are too similar  Therefore we only see the one inflection point Effect of Potassium Ions on Wine Acidity  Titratable acidity values will vary with potassium ion content  Potassium is a significant ponent of grape juice  Potassium ions modify the dissociation equilibrium of anic acids  This is due to binding of anic acid ions (particularly bitartrate) as the potassium salt  Some potassium acid salts react with NaOH during titration, others do not. Effect of Alcohol on Wine pH and acidity  Equilibrium chemistry of wine acids and salts is modified by presence of alcohol  Solubility of some species is lower in alcoholic solution, particularly tartrate salts  Wine has a lesser buffer capacity than juice Consequences for Winemaking  Difficult to significantly alter high pH levels in juice or wine by acid additions  Winemakers must judge effect on pH against effect on flavour and wine balance  Buffer capacity of individual wines will vary depending on their anic acid profile  Cannot eas。