German Prädikatswein

The riper a grape is, the more sugar and thus the more potent a wine you can brew from it. Kabinett wines made from ripe grapes, while Spätlese wines are made from extra-ripe grapes. Auslese wines are generally made from grapes harvested in November and December, where nearly all of the stock has been harvested or rendered unusable. Auslese grapes must therefore be harvested by hand.

The fungus known as the noble rot, or botryis if you want to get technical is entirely harmless. It just wants to suck the water out of the grape. Now as you've gathered, this is a good thing if you want to make German wine.

Beerenauslese wines are made from grapes that have been affected by the botryis. The noble rot makes them very sweet and very rich, and unlike many such wines they keep for a very long time.

The only German wines better than Beerenauslese are Trockenbeerenauslese. Trockenbeerenauslese are rare wines, made of the most condensed grapes. Only rarely will you find grapes that have shriveled on the vine due to noble rot. These wines are sweeter and richer than anything else on the market, and acidic enough to keep things interesting.

Similarly, if ripe grapes are frozen on the vine, all the water is condensed into ice leaving more flavor without having to worry about fungus. These grapes are made into Eisweins which are very sweet and acidic, albeit not so much as the Trockenbeerenauslese.