ALCOHOLOMETRY OF VINEGAR Using a Refractometer
Accurate Determination of Alcohol with Semimicro Still and Refractometer
The determination of the remaining alcohol content in vinegar can be done with simple means at home. But it’s not possible to determine accurately the alcohol content if using directly measurement methods like an alcoholometer (hydrometer), refractometer, or vinometer because in all cases the containing acetic acid, dissolved sugar, and extract distort the measurement. Therefore previously the vinegar sample has to be neutralized and distilled. The distillate is free of distorting substances, so the indicated value of the measurement device like a refractometer is true. But the volume of the sample has changed due to titration and distillation (though not the amount of alcohol when distilling completely), so the value has to be converted accordingly.
Used sodium hydroxide solution: 7.44 ml
Volume before distillation: 0.5 ml
Alcohol content of distillate: 0.8 % ABV
Volume of distillate: 0.41 ml
The alcohol content of the sample is 1.1 % ABV.
ABV: Alcohol By Volume (alc./vol.)