Enzymatic bio-analysis plays a vital role throughout the whole of the wine-making process:

Before the alcoholic fermentation begins, the nutritional status of the grape juice is determined to ensure optimal growth conditions for the yeast. This includes an estimation of yeast available nitrogen as the product of free ammonia, primary amino nitrogen and L-arginine, and the principle fermentable sugars D-fructose and D-glucose.

During the alcoholic fermentation, the level of acetic acid is monitored to detect infection by?Acetobacter sp.?and the level of urea is determined in order to establish whether the wine should be treated by the addition of urease to eliminate the risk of forming the carcinogen ethyl carbamate. Concentrations of acetaldehyde, ethanol, glycerol and succinic acid all rise throughout the alcoholic fermentation phase of the vinification process.

If it is elected to perform a malolactic fermentation, the falling level of L-malic acid and rising level of L-lactic acid are monitored. The falling level of citric acid can also be determined.

Numerous analyses are performed in order to determine the quality, stability and authenticity of wine after fermentation is complete, and include enzymatic assays for: acetaldehyde, acetic acid, L-ascorbic acid, ethanol, ethanol/glycerol ratio, D-fructose, D-glucose, D-fructose/D-glucose ratio, glycerol, D-gluconic acid, D-gluconic acid/ethanol ratio, D-gluconic acid/glycerol ratio, L- and D-lactic acid, L- and D-malic acid, D-sorbitol, succinic acid and urea.