Tta Ph Meter Method Essay

698 WordsMar 8, 20143 Pages
TOTAL TITRATABLE ACIDITY (using pH meter) Introduction Titratable acidity is a measure of the organic acid content of the juice, must or wine sample. The titration determines the amount of organic acids that can be titrated with a basic solution to a pH of 8.2. Equipment 1. 2. 3. 4. 5. 6. 5 ml volumetric pipette (for wine) or 10 ml milk pipette (for juice/must) Mettler Toledo S20 pH meter Heat/stir plate Stir bars 250 ml beaker 10 ml or 25 ml burette Reagents 1. 2. 3. 4. 0.10 N NaOH Phenolphthalein indicator 1% Buffers: 4.00 pH and 7.00 pH Dilute acid and dilute base for TA analysis PROCEDURE: 1. Calibrate the pH meter with pH 4 and pH 7 buffers. 2. Fill a 10 or 25 ml burette with 0.10 N NaOH. 3. Pour 50-75 ml of actively boiling distilled/de-ionized water into a 250 ml beaker. The water is added to de-gas the wine sample (most contain some level of CO2) and does not enter into the calculations, so the measurement need not be accurate. 4. Add 2-3 drops of phenolphthalein indicator. 5. Add dilute base (NaOH) drop by drop, until the water is very pale pink. 6. Pipette 5 ml of the wine sample into the boiling water (or 10 ml juice/must sample). The sample must be added while the water is still very hot. (The heat drives off dissolved CO2.This is more important in the analysis of wine and fermenting must than it is in the analysis of juice). 7. Once the sample has been added to the hot water, cool the solution to room temperature. (To cool the samples more quickly, place it in a cool water bath). 81 M st. Fresno, CA 93721 Tel: 559 485 2692 Fax: 559 485 4254 640 Airpark Rd. Suite D Napa, CA 94558 Tel: 707 224 7903 Fax: 707 255 2019 1165 Globe Ave. Mountainside, NJ 07092 Tel: 908 301 1811 Fax: 908 301 1812 1401 Ware St. Waupaca, WI 54981 Tel: 715 258 5525 Fax: 715 258 8488 “Service With Knowledge” ® Since 1924 PROCEDURE Continued:

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