AOAC Official Method 940.19 Acidity (Volatile) of Wines Exclusive of SO2
By Barium Hydroxide Treatment
First Action 1940
Final Action 1988
Pipet 50 mL test portion into 100 mL volumetric flask. If white,add 2–3 drops phenolphthalein, and neutralize to decided pink with clear saturated Ba(OH)2 solution; if red, add enough Ba(OH)2 solution to bring mixture to ca pH 8, using phenolphthalein as external indicator. Let mixture stand 30 min and keep at phenolphthalein end point by adding more Ba(OH)2 if necessary. Dilute to 100 mL, mix, and filter rapidly through fluted, rapid paper (such as Whatman No. 2). Pipet 50 mL prepared test solution and 1 mL H2SO4 (1 + 3) into inner chamber of still, 964.08A(a) or (b) (see 28.1.30), and stopper. Proceed as in 964.08C (see 28.1.30). Express results as g CH3COOH/100 mL as in 964.08C(a) (see 28.1.30).
Reference: JAOAC 23, 183(1940).
