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THERMO Scientific | A comparison study of total acidity methods for the analysis of wine

Results obtained from the analytical techniques used for evaluating wine, liqueur, and cider during the production process are important for alcoholic beverage making. There will be a difference in the results reported depending upon the analytical procedure used. In Europe, total acidity in musts and wines is defined by the Office International de la Vigne et du Vin (OIV) as the sum of titratable acids up to pH 7.0 using a NaOH solution. Neither carbonic acid nor sulfur dioxide are included in the expression of total acidity. In the United States, the Association of Official Analytical Chemists (AOAC) has established a pH of 8.2 using a titration indicator with phenothalein as the end point. Total acidity is usually expressed as grams of tartaric acid per liter.
There is sometimes confusion with terminology because titratable acidity (TA) and total acidity are often used interchangeably. Total acid content is defined as the concentration of organic acids in grapes and wine whereas TA is a measure of the hydrogen ions consumed by titration with a standard base up to a defined end point.
Wine samples measured with the Thermo Scientific™ Total Acids method are compared in this study to results from the traditional titration method. In Europe, wine samples are often analyzed using the OIV Total Acidity method, an automated titration with a bromothymol blue indicator. The intention of the method reported here is to improve the total acidity measurement in the wine laboratory by introducing an automated colorimetric version of the OIV method. In this report, results from the OIV Total Acidity Type 1 method (OIV-MA-AS313-01) and an automated Total Acids method are compared.

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