Paul Hoover, Owner/Winemaker
Still Waters Vineyards

Winery Equipment Testimonial:

"Upgrading your winery from 1000 cases per year to 3000 to 5000 can be a daunting task. The choices in winery equipment, capacity and price vary all over the place.  The great thing about Ryan is, having been a wine maker for years, he knows how to design things from start to finish. When I harvested my first ten tons of the year at 6:30 a.m., Ryan and his staff were there making sure everything was working correctly. I knew I had made a good decision."

Titratable Acidity

Titratable acid (TA) is a measure of the sum of all the organic acids in juice or wine. In healthy wine, the major acids are tartaric and malic, but all wines contain small quantities of citric, succinic, acetic, butyric, lactic and other organic acids. In the United States, wine acidity is expressed as if all of the acids in the wine were tartaric acid. The titratable acid of juice ranges from 0.4 to 1.2 grams per 100 milliliters of liquid. One hundred milliliters of juice weighs approximately 100 grams, so "grams per 100 ml" is roughly equal to percent.
The taste of wine is strongly related to titratable acid. When wine contains too much acid, it will be very tart or even sour tasting. When too little acid is present, the wine often lacks freshness and tastes flat. Grapes grown in warm areas are usually low in acid, and additions of tartaric acid are often needed to produce balanced wine.
Titratable acid is used to judge maturity, and most winemakers monitor the titratable acid of the grapes for several weeks before harvest. TA is always measured when the grapes are crushed so any needed acid adjustments can be made before fermentation is started.
The titratable acid of normal wine slowly decreases as the wine ages, and a rise in wine titratable acid during the aging period is a danger signal to the winemaker. When the TA rises, acetic acid may be forming, and the wine may be turning into vinegar. Therefore, titratable acid is measured periodically from the time fermentation is complete until the wine is bottled. Small producers often measure titratable acid once each month, but many large producers measure the TA twice a month.
Titratable acid of wine or juice can be measured by several different analytical techniques. However, most wineries use a titration method. This measurement procedure is simple, and the laboratory apparatus is inexpensive.

1st Method: (no ph meter) 
Acid Measurement Materials
Titratable acid can be measured by a simple titration procedure using a calibrated (0.1 N) sodium hydroxide solution. Phenolphthalein solution is used as an indicator to show the titration end point.
The following materials are needed to measure the titratable acid of white wine, blush wine and juice.

 10-ml serological (transfer) pipette
250-ml Erlenmeyer flask
0.1 normal sodium hydroxide
1% phenolphthalein solution
distilled water
Titratable Acid Measurement Procedure
This procedure is satisfactory for measuring the titratable acid of juice or white and blush wines.
1.      Draw 10 milliliters (ml) of juice or wine into a pipette.
2. Transfer the sample into the flask.
3. Add about 100 ml of distilled water and three or four drops of phenolphthalein solution.
4. Fill the 10-ml pipette with 0.1 N sodium hydroxide solution.
5. Titrate with the sodium hydroxide while mixing the wine sample by rocking the flask
6. Stop titration when the sample turns a faint pink.
7. Record the quantity of sodium hydroxide solution used.
8. Rinse the flask and pipettes with clean water.
g/L = ml NaOH x normality NaOH x 0.075 X 1000
                  Sample Volume (ml)
Eg 15 x 0.1 x 0.075 x 1000
      ---------------------------- = 11.25 g/L
Alternative Procedure for Red Wines
2nd Method: using a ph Meter
The above procedure does not work well for dark red wines because the end point is very difficult to recognize in dark red wines. Diluting red wine samples with up to 200 milliliters of water makes the measurement easier, but most winemakers prefer to use the following procedure when testing dark red wines. However, a pH meter, ring-stand and a magnetic stirrer are required for this procedure (see pH measurement below).
1. Place the probe in a ring-stand clamp and arrange the stand so the probe is centered above the stirrer plate.
2. Draw 10 milliliters (ml) of wine into the pipette and transfer it into the beaker.
3. Add about 10ml of distilled water and place the stir bar in the beaker.
4. Place the beaker on the stirrer plate. Adjust the ring-stand so the probe is emersed in the sample but do not allow the stir bar to strike the end of the probe.
5. Turn the stirrer on.
6. Fill the pipette with 0.1 N sodium hydroxide solution.
7. Titrate the wine sample while watching the pH meter.
8. Stop the titration when the pH meter reads 8.2.
8. Record the quantity of sodium hydroxide used.
9. Discard the wine sample and rinse the probe, beaker, stir bar and the pipettes several times with clean water.
Achieve 8.2 ph with sample using Sodium Hydroxide then calculate as follows:
g/L = ml NaOH x normality NaOH x 0.075 X 1000
                        Sample Volume (ml)
Eg 15 x 01 x 0.075 x 1000
      ---------------------------- = 11.25 g/L
Note: If 10ml of sample and 100ml of water is used THen simplified calculation is ml of NaOH used X 0.75 = g/l TA
Eg 15 X 0.75 = 1.25g/l TA

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