Agriculture Reference
In-Depth Information
The solution to this problem is to figure out how much acidity
is in the vinegar. You can do this easily by using the
ingredients in a standard acid testing kit available from all
wine-making suppliers, a pH meter, and a slight change in
procedure. I specify using a pH meter rather than the
phenolphthalein indicator because phenolphthalein turns pink
when the endpoint is reached, and such a color change may be
difficult to discern in vinegar of certain colors. A pH meter
won't trick your eye.
Equipment
1
50ml
beaker
1
10ml
syringe (no needle needed)
0.2N Sodium Hydroxide solution
Distilled water
pH meter
Rinsing the syringe using distilled water after each use, put
2ml of the vinegar to be tested and 20ml of distilled water in
the 50ml beaker. Fill the syringe with 0.2N sodium hydroxide
solution to exactly the 10ml mark. Initially, add 1ml of
sodium hydroxide to the beaker each time, swirl, then test
with the pH meter. As the pH approaches its endpoint of 8.3,
use lesser quantities. Repeat until the solution has a pH of 8.3.
The amount of acid in your vinegar is given by the following
equation:
Percentage Acetic Acid = 0.6 × (10−reading of syringe at
endpoint)
