Drying and Processing Hemp

Steve Knurowski holds A handful of dried hemp. All photos courtesy of Danita Cahill.

A stretch of heavy clay fields that spread alongside McDowell Creek in Lebanon, Oregon was once home to a Holstein dairy farm, operated by Marty Bates’ granddad. Times have changed for the smaller-scale dairies. Competition with huge dairies, which can turn a profit with their sheer volume of cows and milk, elbowed aside smaller dairy farmers. After the black and white spotted cows were gone, the Bates family raised beef cattle and field corn for cattle feed. With only 121 acres, raising beef cattle also proved a challenging way to turn a profit.

From Cattle to Hemp
“CBD started growing,” Bates said about the hemp market. “My oldest son was working in a lab in Portland.”
The Bates family decided to say goodbye to cattle and hello to hemp.
Their first hemp crop was small – they planted only two acres. That was three years ago. “A learning experience,” Bates said about that first year.
The second year was also part of the learning curve. They didn’t buy good seed. Bates shakes his head thinking about it. Around 75% of the plants turned out to be male and were worthless. His family had about given up growing a crop that year, but they found a nearby grower with plants for sale and bought a few hundred. “So we tilled up a strip of dirt,” he said.
Marty’s most important message to other beginning hemp growers: “Buy good seed.”

Drying and Processing Facility
They turned the old milking barn into a hemp-processing facility.
Bates stopped in to talk with hemp growers Tyrel and Linda Rose at another family farm in Lebanon. Their crop is planted each year on Century Farm land that’s been in the family for years.

The Rose family was looking for a processor and wound up processing their hemp at the Bates. They all needed a drying facility, too. So, the Roses put in a dryer at the old Bates dairy, alongside the old milking barn.

Last year, the Bates did hemp processing for several other farms, too. “Kept us busy most of the year,” Bates said. This year is no different. “We’ll go right on into summer with what we’ve got.”

Fall 2018 was dry and clear into November. Not so for the 2019 harvest season. “It rained all through September, making the hemp fields a sticky, muddy mess. The harvest was a real challenge. Equipment got bogged in the mud. Bates drove the harvester, and his dad would pull him through the muddy fields with a CAT.
“Luckily, we had the dryer right here. That kinda saved our bacon a little bit,” Bates said.

Rain and Mud Issues
A cloudy day in early December, 2019, found Bates on a tractor in one of the still-muddy hemp fields, pulling up the used drip tape and cutting and pulling up black plastic. “Some guys use this plastic, some don’t,” Marty said. He uses the black plastic to retain soil moisture.

Normally, the Bates would work up the hemp fields after harvest and plant a cover crop. The plan was to plant crimson clover. But because of the mud they can’t do it this year.

The rain causes other problems besides mud. It also creates mold issues. “A lot of people got mold,” Bates said about the 2019 harvest season. Fortunately for the Bates, their varieties – KLR Farms #1 and #117 – are mold resistant. They made it through October and November mold free, but the weather was cold and plants didn’t mature. A week of freezing conditions down into the 20s in October compounded problems. “It just wasn’t gonna grow after that.” Bates said. Still, they couldn’t harvest it all at once, either. “Have to chop it as the dryer is ready,” Marty said. They harvested as fast as the dryer could do its job, but towards the end of harvest, still lost some of the plants to mold.

Chopping and Drying
Marty and his family use the old dairy equipment for the hemp. They harvest with a corn chopper and load it onto the dryer conveyor belt out of a feed wagon. It travels up into a pre-dryer that warms it up and gets it ready for the main dryer, which finishes the process.

The propane dryer is a model from a company out of Wisconsin. The original design was meant to dry sand used as cow bedding. The dryer can dry about 200 pounds of hemp an hour. After the chopped hemp comes out of the dryer, it’s kept under cover in silo storage bags.

In the Willamette Valley, there is too much moisture during fall harvest season in the way of rain, fog, mist and dew to cut and dry on the ground. Marty said in drier parts of the state they may be able to do that. Some hemp farmers hand cut and hang the plants from the rafters inside buildings to dry. There are two drawbacks to that for the Bates’ operation: It takes a lot of manual labor, and a lot of space under cover to hang dry hemp. Bates admits that hang drying does make a superior product. He tried hang drying some last year and got a better CBD oil yield out of it.
As of early December, the Bates had 60,000 pounds of dried hemp stored and waiting for processing. Bates said they can process 700-800 pounds of dried biomass per day.

The Bates use an ethanol extraction. Ethanol is a solvent that dissolves the oil in the plants. The ethanol and the dried plant biomass go into the stainless steel extractor, which holds 15 gallons. The extractor runs on a vacuum. It spends three minutes extracting, then nine minutes of spin-dry cycles. The liquid is filtered through a series of screens to get out any particles. The finest-mesh screen is one-micron.

The solvent is recovered and reused. The process “basically evaporates it and condenses it,” Bates said. What’s left is the CBD “crude oil,” which looks rather like black tar. The oil has to pass a solvent test, which is a check for residual solvents.

Marty’s son, Sterling, “learned a whole lot of different extractions,” Bates said. Sterling distills some of their crude oil, which further concentrates it. When that process is done, the oil looks more like honey than tar.

Steve Knurowski, who farms six acres of hemp in the Lebanon area, knows the ins and outs of the stainless steel processing equipment and helps the Bates with processing chores. Marty’s wife, Jenna does the books and the billing. “It’s a lot,” Bates said.

The crude oil is stored in plastic buckets with lids. “Ideally, we don’t store it for long,” before it’s sold, Marty said.
Most of Bates’ sales are of the crude oil, which is sold by the kilogram or liter to other labs, where it is further processed.
The Bates have several different customers. They deliver to some. Others pick up their orders at the farm.

• Mold is difficult to deal with in the
Willamette Valley.

• Sometimes deer eat hemp plants.

• Last year they had some problem
with cucumber beetles.

• Bad seeds cause a real problem.

The Bates had very good results with seeds from KLR Farms out of Albany, Oregon. They planted 20,000 to 25,000 plants and only about a dozen turned out male. The Bates also planted a hemp field in Lacomb, which is an outlying rural area of Lebanon. They got no male plants at all in that field.
Buying good seed is key, Bates said. “Don’t go cheap on your seed.”


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