Q: I received a wine kit from my wife almost two years ago. I’ve been meaning to get to it but haven’t had the time. I’m wondering about the package of yeast. What is the shelflife for yeast? Is there anything I can do to revive it? Will old yeast affect the taste or just the fermentation?
— Gary Tanner • Cleveland, Ohio

A:Your yeast packet is almost guaranteed to be past its prime. Yeast cells, even those that have been freeze-dried, certainly do have an expiration date. Using yeast that is more than six to eight months old greatly enhances your chances for encountering such problems as stuck fermentations and off-odors down the road. So it’s recommended that winemakers purchase their yeast from a reputable source (a home winemaking store with high turnover, or from a winemaking supply laboratory like Scott Laboratories Inc.) before every harvest. If you use kits, make sure that the yeast that is included hasn’t been sitting on a shelf for more than six to eight months. If it has, then you might want to buy a fresh packet just to be sure.

Since your kit is more than two years old, I’d also check the quality of the juice in the kit. If it smells oxidized, looks browned or otherwise less-than-perfect, don’t use it. There’s an old saying in the wine business that goes, “Wine waits for no man”. This is even true for kit winemaking, even though you aren’t forced to harvest your grapes at a given time of year, you still want to make sure that your ingredients are of the highest quality.