Total malic Acid: usual method (Type-IV)
OIV-MA-AS313-10 Total malic acid
Type IV method
Citric Acid - enzymatic method (Type-II)
OIV-MA-AS313-09 Citric acid
Type II method
- Principle
Citric acid is converted into oxaloacetate and acetate in a reaction catalyzed by citratelyase (CL):
Citric Acid - chemical method (Type-IV)
OIV-MA-AS313-08 Citric acid (Chemical method)
Type IV method
- Principle
Citric acid is fixed with other wine acids onto an anion exchange column. The citramalic acid is obtained by fractionating the elute.
Lactic Acid - enzymatic method (Type-II)
OIV-MA-AS313-07 Lactic acid
Type II method
- Principle
Total lactic acid (L‑lactate and D‑lactate) is oxidized by nicotinamide adenine dinucleotide (NAD) to pyruvate in a reaction catalyzed by L‑lactate dehydrogenase (L‑LDH) and D‑lactate dehydrogenase (D‑LDH).
Tartaric Acid (gravimetry) (Type-IV)
OIV-MA-AS313-05A Tartaric acid
Type IV method
Organic Acids : HPLC (Type-IV)
OIV-MA-AS313-04 Organic acids
Type IV method
Wine organic acids may be separated and simultaneously determined by high performance liquid chromatography (HPLC).
Fixed Acidity (Type-I)
OIV-MA-AS313-03 Fixed acidity
Type I method
- Principle
The fixed acidity is calculated from the difference between total acidity and volatile acidity.
Volatile Acidity (Type-I)
OIV-MA-AS313-02 Volatile acidity
Type I method
- Definition
The volatile acidity is derived from the acids of the acetic series present in wine in the free state and combined as salts.
Total Acidity (Type-I)
OIV-MA-AS313-01 Total acidity
Type I method
- Definition
The total acidity of the wine is the sum of its titratable acidities when it is titrated to pH 7 against a standard alkaline solution. Carbon dioxide is not included in the total acidity.