Description
Vinegar acidity is determined by neutralization of all available hydrogen ions present in the sample, with a strong base solution:
H++HO→H2O
In an ideal solution, the end point of an acid titration corresponds stoichiometrically to the complete neutralization of the acids present. The pH end point at 8.2 is automatically detected by the pH electrode. End point detection by potentiometric method is more objective than the end point detection using color indicators. For precise results, the sample volume, titrant volume and the titrant concentration must be known. The HI84534 minititrator is designed to determine the acidity of vinegar. The titration is displayed in % w/v (g/100mL) or g/L of the acetic acid. It is important to titrate fresh samples of vinegar. For increased precision, keep the vinegar in capped vessels (avoid prolonged exposure to air). To maintain the high accuracy of the mini titrator requires a simple pump calibration procedure. The pump calibration involves the analysis of a known volume of a known solution. The instrument will perform a differential analysis to compensate for changes in the dosing system. This procedure should be performed daily.
Vinegar is made when acetic acid bacteria is added to an alcohol beverage such as wine. The bacteria will eat the ethanol and produce a tart, pungent liquid know as acetic acid. The acetic acid concentration in vinegar typically ranges from 4 to 9 % (w/v). The pH of vinegar is typically between 2.5 to 3.0, depending on the acetic acid concentration. Vinegar can be made out of anything that has alcohol (ethanol) in it, including wine, beer, and hard cider. The type of vinegar depends on what liquid the ethanol has been fermented in. White vinegar is made a vodka type liquor made from grain, while apple cider vinegar is made from apples and balsamic vinegar is made from grape must. Outside of the United States popular vinegars include rice, coconut and cane. Vinegars are commonly used in food preparation, medicine, agriculture and in cleaning solutions. The titratable acidity of vinegar is determined by titrating the sample with a strong base to a fixed pH. The end point is determined by the potentiometric input and the results are typically expressed as % (g/100mL) or g/L acetic acid. The HI84534 minititrator method is based on the Official Methods of Analysis of AOAC International.