I am currently following a recipe that is unclear with how much yeast to use. It's an extract recipe that comes when ordered makes you order two packets of the desired yeast for the brew. But, the recipe instructions don't specify whether the packet is sufficient for 5 gallons or not. The yeast packet itself also does not specify what capacity it can be used for. Is there a downside for just adding both packets? Or am I just wasting yeast?