How long should I let my brew age?
The longer, the better. Just make sure to keep from exposing your brew to too much air. Some brews take a few months, others as long as a year or more. We recommend letting your brew age (as hard as that might be) for a two main reasons: to get rid of bad-tasting byproducts of the fermentation process, and to bring out delicious flavors that take time to become prominent.
Yeast can produce off-flavors, such as sulfur-dioxide (rotton smell), or even toxic compounds (such as methanol). Given time under anaerobic (without air) conditions, yeast will clean up after themselves to some degree, and undesireable, complex compounds breakdown and evaporate, while many desireable flavor compounds form from the breakdown of more complex ones.