Instant yeast appears similar to active dry yeast, but has smaller granules with substantially higher percentages of live cells per comparable unit volumes. It is more perishable than active dry yeast, but also does not require rehydration, and can usually be added directly to all but the driest doughs. Instant yeast generally has a small amount of ascorbic acid added as a preservative. Some producers provide two or more forms of instant yeast in their product portfolio; for example, LeSaffre's "SAF Instant Gold" is designed specifically for doughs with high sugar contents.