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Influence of ph and temperature on metatartaric acid efficiency in white wine tartaric stabilization
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Resumo(s)
The sensitivity of metatartaric acid (MA) to high temperatures is the main limit for its
actual use in enology. For this reason MA is generally used only for ready-to-drink wines that
are stored for few months in bottle. The objective of this work was to obtain more information
about the use of MA in order to prevent tartaric salts precipitation in wine by monitoring its
effectiveness along the time. Tartaric stability was followed in a white wine during a ten-week
experiment. 10 g/Hl of MA was added to wines with different five pH values, namely 3.0, 3.2,
3.5, 3.7 and 3.9 at room temperature (20°C), and to wines at original pH of 3.2 under three
different temperatures commonly found in real storage conditions, precisely 12°C, 20°C and
35°C. To monitor tartaric stability we used a test based on the electrical conductivity
developed by Boulton (1983). At the end of the experiment we found both a pH and a
temperature effect. It was found a polynomial relation (R2 = 0,85) between tartaric stability
and pH. The highest the pH, the highest the instability and the shortest the protection against
tartrates precipitation. Furthermore, over 20°C we observed a rapid general decrease of MA
effectiveness and that there was a linear relation (R2 = 0,99) between temperature and
tartaric stability, so that we can affirm that the highest the temperature, the higher the wine
instability; this is probably due to a faster MA hydrolysis. Metatartaric acid is surely able to
prevent tartrates precipitation, but since in our experimental conditions it could not protect the
wine for longer than one month, we would suggest extreme prudence about its use
especially during long storage periods
Descrição
Mestrado Vinifera EuroMaster - Instituto Superior de Agronomia
Palavras-chave
wine tartaric stability metatartaric acid electrical conductivity ph temperature
Contexto Educativo
Citação
Morello, A. - Influence of ph and temperature on metatartaric acid efficiency in white wine tartaric stabilization. Lisboa: ISA, 2012, 82 p.