From pomace to pellets

Washington State’s wine and juice grape production leaves behind a mountain of seeds, skins, pulp, and other debris known as grape pomace. But what others see as a pile of waste, Dr. Eric Leber sees as a multitude of value-added products, such as biofuel and gourmet food items.
“There’s a tremendous amount of value embedded in the leftovers of wine and juice making, said the research and development director at FruitSmart, Inc., of Prosser, Washington. Leber has identified more than 50 different products that could be developed from grape processing waste that is typically returned to the vineyard as compost and organic matter.

FruitSmart, founded in 2000, supplies fruit juice concentrates, purées, and essences to the food, beverage, and other industries. More recently, the company has partnered with BRB Seeds, Inc., to provide food and nutraceutical ingredients generated from the fruit-processing stream, such as fruit seeds, oils, fibers, powders, and extracts.

Pellets

In charge of research and development at FruitSmart, Leber has been working on several ambitious projects to turn grape waste into dollars. The biggest effort, funded with grant monies from the Washington State Department of Community Trade and Economic Development, involves creating biofuel in the form of pellets from grape pomace—after the oils and nutraceuticals have been removed. FruitSmart has formulated a grape pellet blend that includes glycerin to improve physical attributes and straw or wood products to reduce any air emission concerns and is using the biofuel pellets to replace propane needed for their fruit-drying processes. Eventually, power generated from the pellets, which are run through a gasifier and turned into combustible gas, could be sold as renewable energy to power companies.

The charcoal pellets that remain from the gasification process are also reusable as a filtering agent, he said, noting that tests show they are as good as current filtering products on the market.

The grape pellets have a higher energy biomass than most organic products, even wood, explained Leber, who believes that the high energy index is likely due to the oils contained in the seeds. The higher energy biomass means that they burn hotter than some other products.

But the biggest potential use of the pellets could be in the retail market for residential pellet-burning stoves. In recent years, pellet-burning stoves have been popular with consumers and promoted as efficient fuel sources. However, consumers have been dismayed by the shortages of the wood-based pellets, especially this past winter.

“Grape pellets could be a viable alternative to the wood pellets,” Leber said, adding that they will be studying the ash that remains from burning grape pellets.

He noted that the Port of Benton is in the process of obtaining intellectual property rights to the pelletizing process.

Other products

“You can also turn grape seed into oils like cold-pressed Merlot and Chardonnay oils,” he said, adding that each wine grape variety has a unique flavor when made into oil. Grape-seed oil is healthier than olive oil, he claimed, with polyunsaturated fatty acids (omegas 3, 6, and 9), antioxidants, and phytochemicals, and it can take high heat during cooking. It takes more than a ton of grapes to produce one gallon of grape seed oil.

A new retail arm of FruitSmart was recently incorporated to market the grape-seed oils. The separate but affiliated company, called AprèsVin, Inc., has already placed varietal and varietal-flavored oils in the Bellevue, Washington gourmet food store Oil and Vinegar.

Leber, who previously taught at Heritage University in Toppenish, Washington, said that 5 percent of the net revenues from sales of the oils will go toward scholarships at Heritage University.

He has also experimented with making flour from the grape seed and milled, dried grape pomace. Flour made from Merlot grape pomace has a purple tinge, which carries through to the finished product when bread is made with the purple flour. Flour made from grape pomace has antioxidants in it, he noted, so it is healthier than regular flour.

“Grape skins have a lot of good stuff in them,” Leber said. “But part of the problem is that there’s no awareness of the value of the grape oils and flours. We need to build consumer awareness to entice and build a market.”

He sees great potential for creating dipping oils, marinades, and other cooking products from grape waste.

Leber estimated that grape waste could produce 450 jobs over the next decade and contribute $50 million in added value to the Washington State wine industry.