I use saf-instant yeast in all my baking. I buy it by the pound and store it in the freezer in an acrylic air tight container. If you only use it occasionally you can get Active Dry Yeast in 1/4 ounce (7 gram) packets. The major difference between the two is that instant yeast can be added directly to the dry ingredients in a recipe and does not need to be proofed (mixed with warm water to start activation). A general rule of thumb for yeast is to add 1 teaspoon for every 3 cups of flour. You don’t want to add too much because a slow rise allows the dough to develop more flavor. This is why many bread recipes call for letting the dough rise overnight in the refrigerator.