Reduction of the grapes as a quality improvement measure in the vineyard, which is also referred to as Auslichten, blind thinning, green crop and green harvest, as well as French Vendange vert (green harvest) or Éclaircissage. The reason for that is that higher earnings and high quality grapes are mutually exclusive. The removal of grapes will increase the accumulation of various substances in the remaining grapes vine achieved. The effects are increasing the extractives, higher Mostgewicht, Leaf-fruit ratio optimization, higher color intensity red wines and better resistance in drought. Apart from the general increase in quality, a positive long-term effect can be achieved, especially for young plants, because they can develop much better.
Already at pruning One can by limiting to a small number of eyes achieve a reduction. However, an extremely strong bleed poses the risk of poor environmental conditions during the life cycle growth cycle like late frost or weak blossom there is a drastic reduction. Furthermore, the vine also has fewer leaves with a small number of cuts. Therefore, thinning out in the summer is the best way to reduce yields, since many risks are no longer relevant and expected earnings are easy to estimate. A desired yield can be calculated with the following formula: average number of grapes per stick x average weight of grapes in kg x number of heads per ha gives the yield in kg / ha.