One question that arises often is whether or not to hydrate the yeast as instructed on the package. Since the instructions that come with the ingredient kits are designed for beginners who have very little brewing experience, they suggest to pitch the dry yeast directly into the wort. This method is very effective at reducing your chances of infection, and does provide a good healthy start of fermentation.

On the other hand, if you rehydrate the yeast in warm water before adding them to the wort, the cell count will be higher, and they may be happier than if pitched dry. I find the difference to be minimal, if at all noticeable. This added step increases the amount of handling of the yeast, and increases the chances of bacterial infection. A brewer who is confident in their sanitation practices, may prefer to rehydrate the yeast before adding it to the wort, but this is definitely not necessary. If you feel comfortable with the sanitation, go ahead and rehydrate, but if you have any doubt, just pitch it dry to be safe.