Rolling through summer, towards harvest, the vineyard team are at work with the final interventions before the grapes ripen and harvest begins. Around veraison (the period where grapes start to visibly ripen, from green to soft yellow or red, depending on the cultivar) is the time where the practice of crop thinning – or green harvesting – is completed.
Green harvesting is the process of removing immature (green) bunches from the vine, before the start of harvest. As the clusters ripen and change colour, it is easy to see which bunches are ripening at a slower pace than the rest. Removing these immature bunches from the vines allows the vine to put more energy into the ripening and development of the remaining grape bunches.
With fewer unripe or irregularly ripe bunches on the vine, flavours become more concentrated. This is especially important for Bordeaux cultivars (where concentrated fruit and depth of flavour is important) such as Merlot, Cabernet Sauvignon and Cabernet Franc.
At Oldenburg – and specifically on the Merlot – the team also removes tiny green bunches that form off the shoulder of the main cluster. The size of these tiny bunches differ from year to year, but if Christo deems them too large, these “shoulder bunches” are removed. There is a noticeable difference in ripeness between these small bunches and the main cluster. Removing them ensures more even ripeness throughout the block. The very tips of the Merlot bunches are also removed if there has been insufficient grape set (easily identifiable by the small, hard, green berries that do not ripen properly). Removing these unripe berries not only improves the ripening of the whole cluster, but also makes bunch sorting easier after harvest.
Timing the crop thinning is extremely important – if you thin too early, the vine may be triggered to produce larger berries. Christo ensures that our green harvesting happens as veraison starts – by then, the vine has already initiated ripening and removing bunches will not affect berry size, keeping them small and the flavours concentrated.
Green harvesting is a labour-intensive process that is completed by hand. The team evaluates each vine individually, identifying underripe bunches and cutting them out one by one. They might also need to go through a block multiple times, as the layout and location of the block might mean different areas ripen at different tempos. The green harvesting process may be time-consuming but is a non-negotiable to ensure improved overall quality of the grapes in the road leading up to harvest.