A year in the life of a wine grape

The start of vintage is like grand final time for winemakers. They’ve been nurturing crops for an entire year to get them to the winery in pristine condition so they can begin the process of transforming them into wine.

Grapes are a perennial crop meaning they grow and bloom over spring and summer then die back during autumn and winter. Unlike other fruits, grapes don’t ripen after they’re picked so there’s a lot riding on picking them at exactly the right time. There’s danger with every season and at every stage of their lifecycle.

WINTER - Grape vines are dormant in the winter months but pruning done during this time is as essential as training in the off season. Cutting back the previous year’s growth and pruning all but the best canes determines the future success of the vine.

In SPRING, sap rises from the roots of the vine and the first signs of new growth appear in the form of bud burst. These buds are very delicate and need to be protected from injury so that they can go on to create shoots and flowers. The flowers of a grapevine are called ‘perfect flowers’ because they pollinate themselves without the need for bees.

SUMMER brings fruit set as the fertilised flowers fall off. At first the berries are quite small, green and hard and not what we recognise as grapes. It’s not until sometime after this (anywhere between 30 to 70 days) that the grapes go through a metamorphosis called Veraison where they increase in size, soften and change colour, taking on more mature hues such as greenish yellow for some white varieties and red, purple and almost black for the red varieties.

It’s during this time that the grapes become more attractive to hungry animals and more susceptible to insects, mildew, rot, other fungi and bacteria. Assuming these don’t damage the fruit, reduce the yields or kill the vines, then the grapes should be ready to be harvested at the end of summer through to early autumn.

As grapes ripen, they become sweeter and their acidity decreases. Generally speaking, the more sugar in the grape, the more alcohol and softer the tannins in the finished wine.

AUTUMN - as picking continues, timing is everything. Pick too early and the tannins may be bitter and underdeveloped. Pick too late and along with the risk of rain and hail destroying the crop, sugar levels may be too high resulting in a flabby, unbalanced wine.

Following the harvest, photosynthesis continues as the vines build up sufficient carbohydrate reserves in their roots and trunks. Once achieved, chlorophyll in the leaves begins to break down as they change colour from green to yellow and fall off leaving the vines to enter their winter dormancy.

Is it any wonder that by the time the grapes arrive at the winery winemakers breathe a sigh of relief? After all, they only get one chance a year! 

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