The manufacturer of Crisco, the best-selling vegetable shortening on the market in the United States, says the unopened shelf-life of its product - if stored in a relatively cool, dry place - is two years. Once the container has been opened, they suggest using it up within a year. We have known containers of shortening to last much longer, and they, of course, are in the business of convincing you to buy shortening every now and then.

But, they say, “if you notice any change in color or appearance, or if your Crisco develops an off odor or taste, it’s probably past its shelf life and shouldn’t be used.” So with your color shift to yellow, it’s probably best to make a change.

Many brands of shortening also include a "Best If Used By" date hidden somewhere on the package. The shortening may still be fresh beyond that point, but the manufacturer will no longer guarantee freshness, and is giving you a subtle hint that you should send some more money their way on your next trip to the store.