There are a variety of methods for this activity. From the laborious exfoliation by hand to the use of sheep, which eat away the leaves, to the various technical possibilities. Most common are devices that suck in the foliage and then pluck it off.
The latest development is a "momentum pusher", which blows large amounts of air through the foliage wall at high pressure and thereby shoots leaves and grape parts downright. This effectively produces a targeted hailstorm, which also loosens the grape structure and thus not only ensures better drying and tanning of the grapes, but also contributes to the prevention of putrefaction by the loose-grained grape structure. Incidentally, the shock contributes to a maturity delay.
These measures are ideally carried out a maximum of three weeks after flowering, so that the young berries get used to the sun early. With increasing berry thickness, the grapes are sensitive to sunburn. The grapes then turn blue and dry.
In addition, the different grape varieties react differently to the sun. With the red wines, a stronger tanning undoubtedly brings more color. Even the cherry vinegar fly, the dreaded new pest, does not like sunshine, so the measure also has an effect here. For many other types of white wine (Gewürztraminer, Muskateller, Huxelrebe) the aroma increases, while for others the sun has a negative effect on the desired aromas (Scheurebe, Sauvignon blanc). Even the Riesling does not like so much sun in the maturity phase and then shows more Riesling-typical flavors in the wine. So the winegrowers have to be very "prudent" to deal with this measure and decide whether from both sides or only on the side facing away from the sun or even not exfoliated.