Most dry pasta is made with only two ingredients: water and a specific type of wheat, called durum. Durum is the oldest form of wheat that's still widely grown and used, and most of it goes into pasta. It's mixed into a stiff dough and then extruded through a metal die, forming it into a range of shapes. Once dried, the pasta is as hard and durable as grain or beans. Some pasta includes eggs, spinach, tomatoes, squid ink or other ingredients to enrich or color it. These specialty noodles are just as durable as the plain variety when they're properly stored.

Most brands of dry pasta are stamped with a freshness date, or "use-by" date. That's the manufacturer's estimate of how long the pasta will retain its flavor and nutrition. Manufacturers want you to continue buying their product regularly, so those dates tend to be conservative. Most dried pastas retain their best quality for up to two years on the shelf, and are still perfectly usable past that date. Their flavor and texture can deteriorate over time, but unless they're contaminated in some way, the noodles are still safe to use.

Pasta is durable but not indestructible, so if you find yourself working with pasta that's old or of uncertain age, it's important to use a little common sense. If the noodles are blotchy or discolored, they've probably been contaminated and you should throw them out. That's also the case if you find insects, egg cases or larvae in the noodles. If your pasta appears to be sound and doesn't smell musty, boil a small amount of water and cook up a few noodles as a test. If their flavor and texture are OK, feel free to use them.

You can improve the lifespan of your pasta through careful storage. Always keep it in a cool, well-ventilated storage area, because heat and humidity degrade pasta's quality. If you're in an especially humid climate, or if insects and other pests are a threat, transferring your noodles to an airtight jar or storage container can help keep them usable for longer. Pasta made with whole grains can be more perishable than conventional pasta, because of the natural oils in the grain. To prevent the oils from becoming rancid, use whole-grain pasta within a few months or store it -- well wrapped -- in your freezer.