Things are starting to kick off in the vineyards all around Niagara now, and there is exciting changes happening on the vines. Veraison is the onset of the ripening of the grapes. In terms of grape development, veraison is the transition from berry growth and berry ripening. This change and transformation is both an internal and external change, although the external is much more noticeable. With the ripening of the grapes, one will notice clusters of multi-coloured grapes, some being green, some red, some purple, and everything in between. In white grapes, the colour change is much less noticeable, with the unripe green berries transforming to golden and yellow colours. In some varieties, specifically Pinot Gris, you can find fully ripened bunches with a singular berry having both green and red colours.
Photo: Pinot Gris grapes undergoing veraison, with a single berry having both green and red colouration
During veraison, acids found naturally in grapes will transform. Specifically, the degradation of malic acid elevates the concentrations of tartaric acid. As acidity decreases in the grapes, sugars start to increase. At harvest for table wine, grapes can see anywhere between 20°-26° Brix. While not a perfect measurement, for an easy explanation, 1° Brix = 10g/L of sugar. The higher Brix measurement at harvest will typically result in higher % of ABV (alcohol) in the finished wine. While not the only thing that winemakers are looking for, veraison is the next big step in a grapes journey.
Photo: Veraison in white grapes
While veraison is a great sight to see in a vineyard, it also begins to raise concerns and risks in the field. With potential for extremely wet conditions, hail, and other adverse weather conditions, the grapes are at their most fragile stage. Heavy rains can cause berries to swell and burst, which pose a heightened risk for disease and moulds forming. With hail, berries can be cut and damaged, which can give the same risks as heavy rains. In addition to weather, during veraison, animals find themselves lurking in the vineyards, getting attracted to the sweet smell from the grapes.