A scale created to indicate how dry or sweet a riesling tastes. Created by the International Riesling Foundation (IRF) in 2007, the chart (which appears on the back label of many riesling wines globally) shows a spectrum from dry to medium dry to medium sweet to fully sweet. It then pinpoints where that wine falls. The IRF scale is based on sophisticated technical guidelines, including the ratio of sugar to acid in the wine. Wines with very high acid, for example, may still taste dry even though they have some amount of residual sugar.