Historically used for dairy cattle feed, almond hulls have had a consistent place in the animal nutrition space. However, a declining dairy herd, in combination with hulls being traded below their production cost, has propelled the industry and the Almond Board of California (ABC) to think about alternative revenue-generating opportunities.
Helping lead this charge is ABC’s Biomass Working Group, formed in 2017 to explore new applications for almond co-products.
“This biomass working group is where business meets science,” said Michael Kelley, chairman of the committee and president of Central California Almond Growers Association (CCAGA). “We have become exceedingly appreciative of the ideas and the potential for the commercialization of products using almond hulls.”
Nutrition potential
One area almond hulls have shown strong potential for is human food products. Because of their high fiber content, natural sugars, phytochemicals, minerals, and processing versatility, they offer multiple benefits in the value-added ingredients food space.
Being that they make up 50% of the almond fruit, they are also abundant in California, creating a reliable and readily available supply for large-scale product development.
While some may question their safety for human consumption, there are positive indicators that prove almond hulls can meet food-grade quality standards. ABC Associate Director of Food Research and Technology Guangwei Huang noted that almond hulls have long been used safely in livestock feed, with no negative effects on animal health or performance. Studies have also shown that pesticide residue and toxicity exposure are not a concern.
To explore these possibilities further, ABC partnered with Mattson, a product innovation firm, to develop samples of what could be done with hulls.
These included a high-fiber bar made with 15% almond hulls, delivering five grams of fiber per serving, and a coffee beverage crafted from coarse-ground, roasted hulls. When added to coffee, almond hull powder helped reduce bitterness and enhanced sweetness. In baked goods like bread, it boosted both fiber and phytochemical content.
Opportunity in “upcycled” markets
Another advantage almond hulls offer is that by adding just 10% or more of almond hull powder to a product, it can qualify for a new third-party “upcycled” certification. While “upcycling” is a relatively new term, it’s become increasingly important to consumers concerned about food waste, noted Daniel Kurzrock, founder and CEO of Upcycled Foods.
After working with upcycled ingredients across various commodities, Kurzrock said he’s seen firsthand the wide-ranging benefits. These include improved sustainability and circularity, the creation of new revenue streams, reduced disposal costs and stronger alignment with shifting consumer values.
“The almond industry is not alone in seeing this potential,” he said. “There’s profit potential for every aspect of the stakeholder chain if we’re able to create uses that are solving problems for companies that buy ingredients.”
Because the end-market for almond hulls is still being widely explored, he also suggested that at this stage in development, it’s important to initiate customer conversations before deciding what to invest in.
“An approach that we find to be working with other materials is doing a pilot to produce some quantity of viable hulls that can go to a miller or a secondary processor to start those customer conversations,” he said.
Steps for commercialization
While it’s not realistic to expect the hulls to be process-ready when leaving the huller/sheller, Huang said efforts to clean and improve their quality can still make a significant impact.
“When the time comes, the industry needs to set minimal specifications or quality requirements for almond hulls for food uses,” Huang said. “We are trying to minimize foreign material, and most importantly, we need the involvement and attention of stakeholders. We’re not expecting the huller/sheller to get hulls to the ready-to-process stage, but they can minimize those foreign materials down to less than 5%.”
The industry must also complete a GRAS (Generally Recognized As Safe) assessment for human consumption, a requirement mandated by the Food and Drug Administration, since hulls haven’t previously been used as a food ingredient. This assessment is expected to be completed by late 2025, Huang said.
Innovations in processing
Several companies in the almond industry are already investing in hull-cleaning systems to ensure they are ready for when almond hulls receive food-safe approval. One of those pioneer companies is Cortez Growers Association.
Recognizing almond hulls as a potential revenue stream, Cortez implemented a cleaning system to remove unwanted materials – sticks, shells, and almond meats – that typically end up in the hull pile. By separating these components, they could sell the almond meats as hash, a “refreshing benefit” to add value to what was once considered waste, said general manager, Dave Thiel.
Other processors are also refining their methods. Corbin Sturdivan of Wilkey Industries explained that current hull cleaning systems include an aspirator to remove the shell from the hull and a detwigger deck to remove sticks from the hulls.
“While this has worked for many years to reduce the fiber content for dairy feed, there is more refinement that we can do with this system by introducing additional screening and additional aspiration,” Sturdivan said.
Through their trials with ABC, Sturdivan and his team discovered that by adding a screen to sift through the hulls, they could be better classified and ranked.
“We would de-twig the product; it would be screened, and the screen would sift out all of the fines from the hulls,” he said. “What is left over is what we would call scalped hulls, and this is your larger, good material created from the early stages of hulling.”
From their observation, Wilkey Industries also found that 1-1.3% of total hull weight can actually be recoverable kernel.
“That translates to roughly 3% of your kernel production that is actually sitting in the hull pile,” he said. “So, by integrating a screen and some additional aspiration, not only can we clean the hulls, but we can also reclaim those kernels and hash that have much higher value to be sold instead of letting them go to dairy feed uses.”
Additional sorting techniques
As cleaning technologies continue to advance, innovations in color sorting are emerging as a key tool for preparing almond hulls for food-grade applications. The team at Chandler Automation has spent time working on this, and the initial models have been successful at “creating pure hull piles in one pass,” said CEO Sean Chandler.
More research is needed to determine where this best fits in the manufacturing process – be it at the huller, processor, or a separate site – and how it will be financially feasible.
“We have to do more research on our side to see the best way to mechanically clean hulls, mechanically feed it, and mechanically pass it through our systems because the technology is there to create that pure, premium hull,” he said.
Looking ahead
As ABC continues to refine its strategy for marketing almond hulls as a food ingredient, the industry is taking proactive measures to position itself for success, and that starts with collaboration among all players involved.
“We are about to begin a new journey to generate more revenue from almond hulls,” Huang concluded. “It will take a while and more effort to develop the market and demand, but if you are interested in creating more value out of almond hulls, many of us can work together to shorten the process.”
Photos: Almond Board of California
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