French see red over 'blue' wine from Spain, as experts challenge claims about how it is produced
A blue-coloured Spanish wine is making a troubled dÃ©but in France, with leading experts challenging the claim that the colour is natural and local winemakers arguing that the description on its label is illegal.
VÃ©ronique Cheynier, director of research at the prestigious National Institute of Agricultural Research, cast doubt on the producerâs assertion that the wine is completely natural.
According to the makers of Vindigo wine, launched in France this summer, it starts out as white wine but turns blue after being passed through a pulp of red grape skin, thanks to the natural pigment anthocyanin.
âI donâât see how anthocyanin derived from red grape pulp can make this wine blue,â Dr Cheynier told the scholarly journal Sciences et Avenir. âEven if anthocyanin-derived pigments that are blue in colour in an acidic medium have be en successfully isolated in the laboratory, these pigments are only present in tiny quantities in grape skin pulp.â
Dr Cheynier added that the pigments are âred in an acidic medium, at low pH, and only turn blue in a basic medium, at a pH higher than seven.â The pH value of wine generally falls between three and four.
Jean-Louis Escudier, a researcher at the institute, which comes under the authority of the French government, said: âA wine with a pH higher than four is unstable in microbiological terms, and oxidises much faster. You can see this effect in brick-coloured red wines, which take on an orange hue.âSource: Google News Spain | Netizen 24 Spain