Almond waste is a growing challenge

It's early October, and Christine Gemperle, a second-generation almond grower near Ceres, in the heart of California, has just finished harvesting the orchards she farms with her brother. The truckloads of almonds the Gemperles produce also generate piles upon piles of by-products in the form of a shell and a hull—a fuzzy, fruit-like outer layer—that together weigh about two to three times as much as the nut. California growers produce a total of up to 1.4 million metric tons (t) per year of almonds, which translates into 3 million t of hulls and 1 million t of shells annually. Although nearly all this waste is used, hulls can fetch just $100 per ton, and shells add next to nothing to the industry's profit. "We're trying to change that equation," says Gemperle, who sits on the Almond Board of California, a trade association that promotes and funds research on the nut.