Wine Glossary
Definition: Trocken
[TRAWK-uhn] German for "dry." Officially, a wine labeled "trocken" must meet the following requirements: residual sugar may not exceed 4 grams per liter (0.4 percent), but it may go up to 9 grams per liter (0.9 percent) as long as the total acidity (see acids) is within 2 grams per liter of the residual sugar. For example, if residual sugar is 9 grams, then total acidity must be at least 7; if total acidity is only 6 grams, then the residual sugar can't exceed 8 grams.
Source: Answers.com; Wine Lover's Companion - R & S Herbst