Sonoma County winemakers find uses for pomace
Everyone knows that juice from Sonoma County wine grapes ends up in the bottle, but what happens to the seeds, skins, stems and solid matter that are left behind after the grapes are crushed?
Some are thrown away, but in the best of all worlds, the byproduct known as pomace will find its way back into the food stream as compost, flour, cooking oil, distilled spirits or even ethanol, a conversion researchers experimented with in 2012.
Each year, California wineries produce more than 100,000 tons of pomace, according to a report co-authored by UC Davis researcher Jean VanderGheynst, a member of the team that studied ethanol conversion. That translates to about 1 ton of pomace for every 5 tons of grapes that are crushed.
At Jackson Family Wines, 80 percent of the grapes go to juice during the fall harvest, leaving 20 percent behind as solid waste, according to Peggy Furth, formerly of Chalk Hill Estates and Vineyard.
“There has to be some value in the 20 percent greater than $10 a ton for cattle feed,” Furth said.
In 2009, she and Barbara Banke of Jackson Family Wines started Sonoma-based SonomaCeuticals as a creative way to raise money for children’s charities, using solid waste from the winemaking process at Jackson Family Wines. Their goal is to use 25 percent of the solid waste created during each harvest to make culinary oils, flour mixes and cookies made from grape seeds or skins.
Marketed under the WholeVine Products brand, the company’s gluten-free cookies, flour and grapeseed oil are now available at more than 70 California stores as well as Alfalfa’s in Boulder, Colo.
“This is definitely one of those practices that can make a big difference in sustainability,” said Allison Jordan, director of environmental affairs at the Wine Institute. The trade group represents California vintners and tracks sustainability efforts by wineries and vineyards, including plans for reusing grape solid waste.
Most wineries put pomace back into their vineyards, either working it into the soil or composting it for mulch. Some haul it away to be made into compost for other agricultural crops or for municipal operations.
Squire Fridell of GlenLyon Vineyards and Winery in Sonoma Valley composts his waste and uses it to fertilize 20 acres of vineyards. He also has considered using the pomace to make grappa, a liqueur that has a long tradition in the Italian wine industry. Doing so would require additional licensing, however, something he doesn’t want to invest in.
“We would love to have a still here,” Fridell said, “but the government sort of frowns on you for making moonshine.”
Michael Muscardini of Muscardini Cellars has found a creative way to make and sell grappa at his Kenwood tasting room. He hires Prohibition Spirits Distillery in Sonoma to process some of the pomace produced by his winemaking.
To make it, Muscardini said, he reserves enough of the grape juice from each year’s crush to make about 50 cases of grappa and combines it with a cake of pomace, making a slurry that is fermented and distilled by Prohibition Spirits.
Although he doesn’t make a lot of money from the grappa, Muscardini said it serves as a unique offering that complements his Italian heritage.
“Grappa is the essence of wine,” he said, but because it contains 40 percent alcohol content, alcohol regulations prohibit him from offering samples to his tasting room clients.