RESOLUTION OIV-OENO 438-2011

UPDATE OF THE METHOD FOR DETERMINING pH (METHOD OIV-MA-AS313-15)

The GENERAL ASSEMBLY,

IN VIEW of article 2, paragraph 2 iv of the Agreement dated 3 April 2001, establishing the International Organisation of Vine and Wine,

Following a proposal made by the Sub-commission Methods of Analysis,

Considering the method relating to the determination of pH (METHOD OIV-MA-AS313-15) updated in 2009,

IN VIEW of the studies presented to the Sub-commission Methods of Analysis

HAS DECIDED to: modify paragraph 2.1, to replace the Note in paragraph 3, to rewrite paragraph 4.2 in type I analysis method AS313-15, included in Appendix A to the Compendium of International analysis methods for wine and musts, as follows:

Title	Type of method
pH (Method OIV-MA-AS313-15)	I

*the original language from which this text was translated is: FR

UPDATE OF THE METHOD FOR DETERMINING pH

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2.      Apparatus

2.1.      pH meter with a scale calibrated in pH units and enabling measurements to be made to at least ±0.01 pH units.

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3.      Reagents

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Note. Commercial reference buffer solutions traceable to the SI may be used.

For example:

• pH 1.679 ±0.01 at 25°C
• pH 4.005 ±0.01 at 25°C
• pH 7.000 ±0.01 at 25°C

4.      Procedure

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4.2.      Calibration of the pH meter

The pH meter must be calibrated at 20°C using standard buffer solutions connected to the SI. The pH values selected must encompass the range of values that may be encountered in musts and wines. If the pH meter used is not compatible with calibration at sufficiently low values, a verification using a standard buffer solution linked to the SI and which has a pH value close to the values encountered in the musts and wines may be used.

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