wrapped in plastic. Cheeses lose moisture over time, and with this also comes dissipation of flavor. Very old cheeses that are already old (and by that we mean aged) to begin with-- like parm, gouda, or gruyere-- often won't taste like much of anything. Semi-soft cheeses, like washed-rinds, might become softer and stronger tasting. Again, only by tasting will you know if your cheese is past its prime. Trust your palate! As a rule of thumb, perishability is based on moisture content. A fresh, soft cheese that was made only days before it landed on the shelf will be much more perishable than a cheese that ages for a year before being ready for sale. Fresh cheeses are pretty easy to figure out: If they've spoiled, they'll taste of spoiled or sour milk. Your sense of smell will come in handy with this category of cheese, since fresh cheeses shouldn't smell like much of anything. If they do, they've seen better days. They may also develop patches of blue or pinkish mold. But don't be afraid of all mold. Mold on harder cheeses can be scraped away to reveal a completely edible and potentially still tasty cheese. For tips on cheese storage, check out The Cheesemonger's Top Ten Rules for Ultimate Cheese Sanity.