Term for all acids which, in contrast to volatile acids, remain in the wine after distillation (evaporation). However, it is not possible to draw an exact line, as there are also "medium volatile acids". The three most important non-volatile acids are tartaric acid, malic acid and citric acid, which make up about two thirds. Lactic acid (already rather medium volatile), galacturonic acid, gluconic acid, glucuronic acid, glycolic acid, oxalic acid and mucic acid are present in smaller quantities. The amount results from the difference between the titratable acid determined by titration minus the volatile acids. For this purpose, the value determined as acetic acid (all volatile acids) must be converted to tartaric acid by multiplying by 1,25: titratable acid minus (volatile acid x 1,25) = non-volatile acid in grams per litre, expressed as tartaric acid. Non-volatile and volatile acids give the total acidity. See all wine ingredients under total extract.
I have great respect for the scope and quality of the wein.plus encyclopaedia. It is a unique place to go for crisp, sound information on terms from the world of wine.Dr. Edgar Müller
Dozent, Önologe und Weinbauberater, Bad Kreuznach