Active dry yeast begins as compressed yeast but the press cake is extruded through perforated plates in the form of thin spaghetti-like strands. These strands are cut into elongated pellets as they enter the fluidized bed dryer. The combination of strain chosen for active dry yeast, the growth conditions, and the drying method tend to favor stability over activity. This means that active dry yeast has lower gassing power than compressed yeast in lean dough. Active dry yeast is available to commercial bakers in 500 g packets. It has approximately 93.0% solids and 7.0% moisture content. The shelf life of active dry yeast stored at room temperature is approximately 1 year from its manufacturing date. Once opened, it will retain its activity for roughly a month under the refrigerated conditions in an airtight container. In order to rehydrate, one part yeast is dispersed in four parts warm water for 10 minutes.