What Happens When Soap Goes Bad?
Can soap go bad or expire?
You may have accidentally left a bar of soap sitting around and noticed that it doesn’t quite smell as good as it used to. This might be especially true for organic or handmade soap. You might be wondering if soap can go bad like food in the refrigerator or if it can expire like old medication or other personal care products. Well…Smutzies, of Bucks County, has the answer for you!
The short answer to this is no.
If left undisturbed, bar soap remains soap for years. It should still be just as effective at cleaning no matter how old it is. However, certain changes in a bar of soap make it smell less good and seem less pleasant to wash with. As soap gets older, there are two main ways it deteriorates. The first way is that the fragrance evaporates out of it, and the second way is that some of the oils may go rancid.
There is one piece of good news about soap and essential oils. Most often, the out layers of the soap have lost their fragrance. As you use the soap, the out layers are washed away, and you expose the inner core that still has plenty of scent left. So, if your soap doesn’t smell quite as strongly as it used to, you might as well take a chance and use it anyway. You might be pleasantly surprised after a few showers.
It’s not that big of a stretch to assume that soap made from natural or organic ingredients might not last as long because natural or organic ingredients don’t last as long as synthetic, or because they don’t include any preservatives, etc. Essential oils only last for so long and in natural soap making, many soap makers use a recipe that leaves a little bit of oil in the soap that doesn’t react with lye. This makes for a very gentle soap bar that is pleasant to wash wish.
Polyunsaturated oils such as corn, canola, and soybean oil go rancid more quickly than others. Fortunately, monosaturated oils such as olive and avocado oils do not go rancid as quickly and behave pretty much the same way in a soap formula. You can tell if soap has gone rancid because it has a stale or acrid smell. It also develops spots.
A lot of soap makers might tell you to throw out your stinky, spotted soap and buy new because they want you to buy more soap. But we say use it! We’re guessing if you are shopping for natural handmade soap, you are probably very conscious of what you put in and on your body. We aren’t saying to use rancid soap to wash yourself but don’t waste it either. Use it to wash your car or your bathtub, but probably not the dog. Or use it to pre-treat stains in your clothes. Maybe to wash the dishes, that is, if you’re feeling lucky!