Quick-rising yeast can also be called bread yeast, instant yeast, though you don’t get an instant rise, or rapid rise yeast. It looks similar to most forms of active dry yeast and comes in small packets. These packets have expiration dates, and you should be sure to take note of the date before you use it. Bakers note that the main difference between quick-rising yeast and active dry yeast, or other forms like fresh yeast, is that you can rise bread products in about one half to one third the time. Since bread making can be a lengthy process, this is often viewed as an advantage.
How does quick-rising yeast work faster? It has lower moisture than active yeast, and it's made with more nutrients. The individual particles of yeast are smaller and will absorb moisture quickly, getting to work faster. Instead of proofing the yeast, many people simply add instant yeast to dry ingredients, which explains its use in bread machines. Some forms of quick-rising yeast have ascorbic acid, which may help increase the volume of rise too, in a quicker time period.
Another difference between quick-rising yeast or instant yeast and active dry is that it may contain more live cells per package. This could also accelerate the rate at which dough rises. This seems like great news if you want your bread to rise quickly.
It’s important though, to check recipes before substituting instant or rapid yeast for active dry or other forms of yeast. In some cases, quick-rising yeast is preferred and recommended. This is the case if you’re preparing bread in most bread machines, where recipes will call for bread machine yeast, instant yeast or the quick rising variety. In other recipes, you may want to check to be sure if this substitution is okay, though some cooks claim it’s absolutely fine to make a direct substitution.
There are bakers who do dispute the quality of quick-rising yeast when it comes to the taste of baked goods. Some believe that the yeast tastes less “yeasty” and doesn’t impart that special baked bread taste and aroma. Others say they notice very little difference between those breads made with instant or quick yeast and those made with active dry yeast. Some artisan bakers may avoid quick rising forms because they want to create breads in more traditional ways, when quick-rising yeast was clearly not available. Instant or rapid versions of yeast have only been widely available in commercial form since the mid 1980s.