Riesling remains underrated and largely under-consumed in the U.S., and recently two dozen German Riesling producers and importers descended on San Francisco to offer tastes of (primarily) their 2008 and 2009 vintages.

One of the reasons why German Riesling is so ignored here is likely due to its complicated categorization system, which puts wines into five major categories while also offering opportunities for the producer to add designations representing quality and sweetness level. It’s quite complicated — and not helped by being in thick German — and I won’t even start to try to explain it all here. Give this Wikipedia entry a try if you’re a Riesling novice; it’s not the clearest explanation by far, but at least it’s a start.

As for the wines, it’s rare to encounter a tasting with such a clear favorite, but I was blown away by all the wines of Dr. Loosen, one of Germany’s most awarded Riesling producers. Its best wine was the dry Kabinett Blue Slate bottling, a crisp, perfectly balanced example of everything young Riesling should be, full of fruit, minerals, and just the right level of acid. Some old Rieslings were also being poured, and it was interesting to see how these ’90s-era wines had begun to fade, giving off those telltale petroleum notes as they mellowed over the course of more than a decade.

Tasting notes follow.

Riesling & Co. World Tour 2010 Tasting Report

2008 Prinz von Hessen Riesling / B

2008 Prinz von Hessen Riesling Kabinett / B+

2008 Prinz von Hessen Riesling Kabinett Johannisberger Klaus / A-

2008 Prinz von Hessen Riesling Erstes Gewachs Johannisberger Klaus / A- nice balance, single estate wine

2008 Prinz von Hessen Riesling Auslese Johannisberger Klaus / B

2009 Graf von Schonborn Kabinett Hallburger Schlossberg / C+ cheap finish

2008 Graf von Schonborn Kabinett Hattenheim Nussbrunnen / B- toasty

2008 Jean Buscher Dornfelder Rotwein / C+ a red oddity

NV Jean Buscher Muskateller/Gewurztraminer Dornroschen / B- very strange, like strawberries

2008 G.A. Schneider Riseling Niersteiner / B not much presence

2007 Dr. Fischer Riesling Kabinett Ockfener Bockstein / A-

2008 Dr. Thanisch Riesling Kabinett Bernkasteler Doctor / B- off herbality

2008 Dr. Loosen Riesling Kabinett Blue Slate / A amazing balance, really great combo of fruit, minerals, and body

2008 Dr. Loosen Riesling Spatlese Urziger Wurzgarten / A-

2006 Dr. Loosen Riesling Beerenauslese BA / A- very rich

2008 Robert Weil Riesling / B- plain

2008 Robert Weil Riesling Kabinett / B+ racier, but on the mild side

2008 Markus Molitor Riesling Haus Klosterberg / B- not a fave, odd character

2008 Markus Molitor Riesling Spatlese Bernkasteler Badstube / B-

2008 Max Ferd. Richter Riesling Kabinett Graacher Dompropst / A-

2008 Max Ferd. Richter Riesling Kabinett Brauneberger Juffer / A- perfumed

2008 Max Ferd. Richter Riesling Spatlese Whelener Sonnenuhr / B+

2009 St. Urbans-Hof Riesling St. Urbans-Hof / B+ fruity citrus

2009 St. Urbans-Hof Riesling Kabinett Ockfener Bockstein / B+

2009 St. Urbans-Hof Riesling Kabinett Piesporter Goldtropfchen / B

2007 St. Urbans-Hof Riesling Auslese Piesporter Goldtropfchen / A-

2007 S.A. Prum Riesling Auslese Piesporter Goldtropfchen / B earthy, meaty notes atop peaches

1997 Balthasar Ress Riesling Spatlese / B- fading

1994 Paul Anheuser Riesling Auslese / B dusty