MAKE SURE YOUR YEAST IS FRESH – Yeast is a living organism, and in order for it to work, it needs to be alive when you use it. To test whether yeast is active, combine it with the amount of warm water asked for in the recipe. Then add a small amount of sugar (1/8 tsp is all that is needed). The sugar acts as food for the yeast, and if it’s alive, it will begin to bubble within approximately 10 minutes. If there is no bubbling, then you know the yeast is no good.