For the winemaker, this means getting up early in the morning and occasionally at night to read into the rising sun. It is coldest as soon as it gets light, then the temperatures around noon currently rise quickly above 20 degrees. Many people are not even aware of the progress of the harvest, as there are only a few tractors and grape harvesters around during the day. In addition, due to the excellent health of the grapes, there is no need to rush the harvest.
The ideal reading temperature is 14 to 15 degrees, then you don't have to cool the grapes or the must immediately in order to cause a slow fermentation start. If the temperatures are higher, pre-clarification by sedimentation (allowing it to settle) is no longer possible and a great deal of energy has to be used immediately to cool the must. At most, when making red wine, where fermentation takes place with the skins, a few degrees more can be tolerated, here you force a quick start of fermentation.
Due to the warm temperatures, you can already say that the 2020 vintage itself will have a moderate acidity. The development of the fruit aromas in the grapes is better the more it cools down at night. The yields spread very widely across Rheinhessen. Where there have been a few rain showers in the last few weeks, they are very good; where the soil has dried out like a steppe, the vintners harvest below-average quantities.