Why do pH levels matter in wine?
Alex Silverman, Norwich, asks: I am always a bit baffled when you refer to pH in your articles. Can you please explain why it is so important to wine and winemakers?
Rob MacCulloch MW answers: pH measures the strength of acidity, but not the volume of acidity.
In other words, it’s not how many apples one is buying, but how acidic those apples taste. Analogies aside, pH governs many elements in winemaking and is consequently a crucial parameter.
One important effect of pH concerns wine stability – very simply, adverse organisms are far less able to survive in wine that contains strong acidity (low pH).
Therefore, lower levels of sulphur can be used during winemaking, as there are simply fewer ‘bugs’ in the wine that could cause spoilage.
In terms of colour and flavour, wine with low pH has a brighter hue, with acid that tastes fresher, both of which are generally desirable wine characteristics.
When those advantages of low pH are also combined with increasing the speed of fermentation and increasing ageing potential, the importance of pH cannot be overstated.
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