Adopted into English use, veraison is originally a French viticultural term meaning ‘the onset of grape ripening’ and heralds harvest time.

Although stunningly dramatic, veraison is only a short, intermediate stage when the skins of young, immature grapes, rapidly start to take on their final colour. Characterised by an extraordinary kaleidoscopic palette of tints in the vineyard, it refers to those few weeks when vines show bunches part green and part yellow or red, depending on the variety.

At first, the colour of all grapes is bright green due to the presence of green chlorophyll in their skin but it changes rapidly as chlorophyll is replaced by other organic pigments such as anthocyanins in red grapes or carotenoids in white varieties.

As the skin becomes more transparent, the colour of white wine grapes will turn from green to a yellowish green or even golden yellow. In red grapes the transition is visually more noticeable since the berry skins go from a similar green colour to a bright ruby, deepening to a dark black cherry hue.

The final depth and exact shade will depend on the variety itself. For example, grape varieties such as Cabernet Sauvignon, Syrah and Merlot will be almost black whereas grapes such as Ġellewża, Grenache and Sangiovese will be lighter and redder or purple in comparison.

But the change in the colour of the grapes is only part of the story. Other important changes in grape development occur also.

The berries grow to about twice their size and start to soften. The summer months offer the vines an abundance of long days and bright sunshine which creates energy resulting in amounts of grape sugars. Glucose and fructose begin to be deposited inside the berries while sour acids get broken down as the grapes mature. Berries change from being very tart, herbaceous and acidic to tasting more fruity and complex.

This is the time of year when Malta’s vineyards are spattered with brightly coloured dots in new shades of yellow and red hues peeping through leafy vine canopies ready to have their ripe crop picked.