Instant yeast, which is also known as rapid rise yeast or bread machine yeast, has become the type of yeast I always use. Why? It makes bread baking easier and the results are just as good as with active dry yeast.
With instant yeast, you skip the step of dissolving the yeast in warm water. It is more finely ground than active dry yeast and therefore absorbs moisture much faster. As the name implies, instant yeast also works more quickly than its counterpart.
Another difference is that when using instant yeast with gluten bread, only one rise time is needed and the dough is not punched down. That’s not significant to us gluten-free bread bakers because our dough only requires one rise time anyway.
If you are following a recipe that calls for active dry yeast, use about 25% less of instant yeast. Mix the yeast in with the dry ingredients and combine the wet and dry ingredients according to the instructions.
Bread machine yeast is easily found at grocery stores. I buy vacuum packed instant yeast from BJ’s wholesale club. SAF Instant Yeast is one brand I have used. Once I open the pack, I put some into a small container I keep in the refrigerator and the rest of the package I close, put it in a zip lock bag, and store it in the freezer.
You’ll notice that my recipes use instant yeast. If you don’t have instant, you will have to dissolve the yeast in the warm liquid. You may also want to increase the amount of yeast a little. If you haven’t given instant yeast a try yet, I hope you will soon. I think it will quickly become your preferred type of yeast.
this information i copy from http://www.glutenfreehomemaker.com/