Can You Use Expired Cake Mix?

Open any pantry, and chances are you'll find a couple of boxes of cake mix, sometimes of questionable age. Perhaps they were on sale last year as a two-for-one deal, or you grabbed an extra mix intending to make cupcakes on a rainy day but forgot. Boxed cake mix is great because it's super easy to put together and has a long shelf life, so you can have one on hand for an emergency school bake sale. But cake mixes don't last forever, and they have a date on the box for a reason. While there is a little leeway for baking a boxed cake after the expiration date, you're taking a gamble. An expired, unopened cake mix won't make you sick, but there's also a big chance it won't rise properly.

The convenience factor of a cake mix is that all the dry ingredients are already sifted together, including its leavening, which is usually baking powder. All you need to do is add oil, eggs, and milk or water. The leavening is what degrades fastest, and even if it's in an unopened package, it starts to lose efficacy after only a few months. After that, it simply won't work as well, and your cake can come out flat and dense unless you do a little doctoring with the ingredients.

Baking a cake is a little like a science experiment, which is why everything needs to be measured correctly. There's a delicate balance between moisture, dry ingredients, and heat that creates the crumb of a cake, which is its texture. The leavener is the star player here because when it's mixed with liquid and exposed to heat, a chemical reaction happens that releases carbon dioxide. Those gas bubbles expand the space inside the batter, making the cake rise. Eventually, the gas is released when the cake sets, leaving air pockets in their place.

Because leavener plays such an important role, it's crucial that your baking powder or soda is good so it can do the hard work of puffing up your ultimate chocolate cake. As their shelf life wanes, leaveners lose their ability to pull off their lifting magic. The USDA says that baking powder has a shelf life of only around six months if it's unopened and about three months if it's opened. Baking soda lasts a little longer: Around 18 months if it's unopened and six months if it's opened, according to the USDA, but that's still not forever. 

With all that said, an unopened boxed cake mix is safe to eat after its expiration date. The typical expiration date range is usually six months to a year, which is the range when the manufacturer feels that it can guarantee that the mix will rise correctly and taste good. Does It Go Bad advises that you can use an expired cake mix up to six months after the expiration date, and it'll probably work just fine (but you can't always trust it). The ingredients themselves, however, are dried and sealed so they can last up to two years after the expiration date.

The problem, as we know, is the leavener, which is an easy fix: Just add more fresh leavener. The older the cake mix, the more leavening you should add. For example, if your cake is six months past the expiration date, add ¼ more leavening needed for an equivalent cake recipe. If it's a year past its expiration, add half the amount, and so on.

Remember that there are other ingredients in your cake mix, like flavorings, which also lose quality over time. If your mix is made with nut-based flours, those also degrade. If your mix is more than a year or two past its date, it's time to toss it and start fresh or use it in a different recipe that doesn't require a perfect rise, like pancakes in a pinch.