Do some of the steep vineyards in Germany and Alsace really require pickers to rappel down to harvest?
Short answer, yes:
Alsace is a region in France on the border of Germany, so their terroirs are comparable and the styles of wine they produce are similar.
Quote from "Great Wine Made Simple" by Andrea Robinson, page 121.
Long Answer: Not as much as they used to thanks to technology.
For most of the history of the Mosel, there simply haven't been mechanical harvesters that can climb the steep slopes effectively without being a huge hazard. They have had to rely on hand harvesting at a huge expense each harvest. Now, some engineers at Geisenheim University in Germany are trying to change that. Their robot, named "Geisi" after the university, has a low center of gravity that can help it navigate the steep slopes without toppling over.
It not only looks like an awesome Battle Bot, it could save vineyards a ton of money and time when it comes to harvesting. Most of the top-tier vineyards, especially those producing late-harvest wines, will still most likely choose to hand-harvest in order to ensure they are using only the very best grapes. Even the smartest mechanical harvesters can't select a grape the perfect level of ripeness the way that a trained human eye can, but this is a great start for lower-tier table wines.
Check out more about Geisi here!