The amount of alcohol produced by the fermentation depends, as previously stated, upon the initial sugarlevel and the strain of yeast used. Approximations can be made from the soluble solids level of the grapes, but the final alcohol level of the wine still needs to be measured for labeling purposes. As alcohol is a toxin as well as an intoxicant, there are strict regulations surrounding its production. Terminology for alcohol in winemaking is therefore complex, and can be confusing. Alcohol that could be made from the natural sugar in the wine is termed ‘potential alcohol,’ and needs to be determined before the fermentation process starts. Once this sugar has been converted to alcohol, it is termed the ‘natural’ alcohol of the wine. When alcohol is derived from added sugar (chaptalization), the wine is termed ‘enriched’ and this amount (according to UK legislation) has to be less than 3.5% (4.5% in poor years) (Morgan et al., 2006). ‘Actual’ alcohol is that which is present in the wine after fermentation and chaptalization, and ‘total’ alcohol is determined by adding the contribution of potential alcohol from residual sugar in wine to the actual alcohol concentration. The way in which the alcohol content is displayed on the label is also subject to regulation, for example, the alcohol figure on a wine label must be accurate to within ±0.5% and prominently displayed. Duty is usually payable according to the alcoholic content of the wine. Alcohol is measured mainly by ebulliometry or distillation followed by hydrometry or pycnometry (Iland et al., 2004), but there are many other methods (see Sections 4.3.2 and 4.6.3).