When are red grapes green?

Aug 16, 2022Roisin Kirby
When are red grapes green - wine at home

I love this time of year, when the young green grapes start to mature and change colour. It’s the time when the mature grape announces itself in its true colours. All young grapes are green, but from late July and August in the Northern hemisphere, they start to change colour.

Red grapes are the most noticeable of course as they change from green to a deep purply red, but white grapes change too to become more translucent and perhaps with a yellowish hue.

This explains why all grape juice is white – and never red. See my blog post on why Rosé is pink.

The French word for this process is ‘la véraison’ which you will sometimes hear bandied about in wine circles. It’s one of the most significant points in the life cycle of a grape and of a vineyard as not only does the grape change colour, but it is the point when the vine shifts its energy from growth through photosynthesis to ensuring the grape has as much sweetness as possible as it ripens.

The change of colour also indicates that the skin of the grape is toughening up, developing those very useful polyphenols (antioxidants) that protect it from the elements.

It’s also a good indication for the wine grower about when the grapes may be ready for harvest – as they will know from experience where their grape variety falls on the scale of things – but usually it’s between about 30 – 70 days, depending on the region and the amount of sunlight.

I captured some great photos during my recent trip to the Loire where La Version is in full swing after a few weeks of non stop sunshine. The further north you go, the later this process is likely to be and the further south, the more advanced. 

Why is red wine red?

It is the skins of the red grape that give the finished wine its colour, and not the juice, and it is also the part of the grape that gives life to the idea that a glass of red wine is good for you as the red grapes contain far higher levels of polyphenols.

The amount of time the juice stays with the crushed skins will dictate the final colour of the wine and will come down to the decision of the wine maker. Each grape variety will require slightly different treatment and the colour of each wine will vary accordingly.

If you have any questions about the veraison, or any questions about wine you'd like answered, do get in touch! 


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