Most peanut butter is made from blanched peanuts. Blanching is the technical term for removing the testa, or seed coat, from the peanut kernel. What's the testa you ask? That's just science-speak for that dark reddish, papery coating on every peanut.
Perhaps now you're thinking, "Wait a second. Why are they removing the skins from my peanuts? Didn't I just read somewhere that skins are healthy?" Peanut skins have traditionally been treated by peanut processers as a waste product and sold off as animal feed. But that is changing.
One study from 1996 showed that some peanut skins contained up to 17 percent oil and contained fatty acids which, if extracted, could be valuable for nutrition and cosmetic firms.
But there seem to be benefits from eating peanut skins as well. Not only are they high in fiber, but they contain reservatrol, the same antioxidant that red wine is famous for, which is also an antimicrobial, and which in lab tests has been shown to lower blood sugar and may be an important weapon in the fight against cancer.
A more recent study in 2009 showed that roasting peanuts with their skin on actually increased the amount of antioxidants in peanuts.
Peanut butter isn't traditionally made with peanut skins for a number of reasons, among them concerns about freshness. If not handled properly, the natural oil in the peanut skins could may become prematurely stale and cause off flavors when the peanut butter is being made. Also, consumers tend to prefer peanut butter without the reddish brown specs that making them with skins on produces.
The best place to get your peanut skin fix is from roasted in-shell peanuts you can buy at a stadium or in the produce section of your local supermarket. And if you do find them in a can or a jar, just make sure they're unsalted, so you can control the amount of sodium you're adding to your healthy snack!
Do you like eating peanuts with skins on or off? Do you ever roast your own at home?
This post may contain links to Amazon or other partners; your purchases via these links can benefit Serious Eats. Read more about our affiliate linking policy.