There are many types of alcohol found in wine and other fermented, alcoholic beverages.
Alcohols have the potential to form esters adding to the flavour complexity of wine.
During the distillation of alcohol, alcohol can behave differently in solution or the vapour phase, depending on the concentration of the various components present (see alcohol distillation).
Certain compounds, (predominantly aldehydes), present in fortifying spirit (esp. SVR) can exist in a less detectable form at high alcohol concentrations but become apparent when they exist in lower alcohol concentrations with a higher acidity, such as the fortified wine (more).
For this reason fortifying spirit should be assessed by acidification and dilution to the final expected fortified wine alcohol concentration (more).
