Hung out to dry, wild fireweed and vervain infuse the Ashland herb school with their grassy, medicinal aromas.

Hung out to dry, wild fireweed and vervain infuse the Ashland herb school with their grassy, medicinal aromas.

The plants number among nearly 500 remedies at herbalist Jon Carlson's disposal, but most already infused their essence into bottled elixirs lining the room's walls. Standing shoulder to shoulder, racked horizontally like wine and decanted into portable vials with eye-drop dispensers, tinctures compose two-thirds of Carlson's pharmacopeia.

"They have a nice long shelf-life," says Carlson, 44. "Some things are good for decades — that's a whole lot longer than a dry plant."

To maximize the beneficial properties of herbs, Carlson prepares almost all tinctures from fresh plants. The process — one of four herbal media — immerses botanicals in pharmaceutical-grade alcohol distilled from certified-organic corn. The basic ratio is one part fresh herbs to two parts alcohol diluted with a little water, but that formula varies per plant, says Carlson.

The alcohol dehydrates the herb, drawing out its chemical compounds and preserving them, says Carlson. At least 20 percent alcohol is needed to maintain the mixture, which if done correctly is stable at room temperature. Devoid of intoxicating effect in a therapeutic dosage of tincture, alcohol is the necessary solvent because not all plant-based substances — namely resinous or oily ones — dissolve in water, says Carlson.

"Much of the medicine is tied up in the aromatic oils and resins," he says.

Tinctures have the additional advantage of rapid absorption by the body. Applied under the tongue, tinctures penetrate the mucus membrane and enter the bloodstream, bypassing the digestive pathway where herbal teas and capsules are broken down, says Carlson. Tinctures also can be added to a broth or beverage and swallowed.

"A tincture is very easy to take with you," says Carlson. "It's not the only way to go, but in many ways, it's preferable."

Making tinctures, as Carlson's students learn, requires some understanding of mathematical ratios but little in the way of specialized equipment. A lesson at Vitalist School of Applied Herbology looks almost like a cooking class as participants use ordinary kitchen knives and cutting boards to chop leaves and roots before packing them into quart-sized Mason jars; they strain finished tinctures through coffee filter-lined funnels into glass measuring cups.

"It's like learning to do canning ... dehydrating," says Carlson.

While not actual food, herbal tinctures can provide a feast for the senses.

"It'll be a beautiful, emerald-green," says Carlson, running a knife through a mass of alcohol-soaked vervain to release trapped air bubbles, preventing oxidation of the herb.

The tincture is ready for pressing a week to 10 days later but can be let alone for a few months. In summer when he gathers the most herbs, Carlson starts a lot of tinctures but may not get around to pressing them until fall. If he makes a tincture from dry plants, Carlson lets it steep for at least two weeks.

"Tinctures are traditionally done with the lunar cycle — started on the new moon and pressed on the full moon," he explains.

After pressing, the plant solids either are composted or dried for tea, the latter if they have a pleasant flavor. The sweet root that 40-year-old student Aimee Keller gathered on Grizzly Peak and then tinctured imparts a strong taste of licorice while soothing the stomach and dilating the airways, says Carlson. The vervain, however, is too bitter for most people to take in tea, even if it does have myriad uses, from relieving pain and inducing sweat to strengthening the reproductive system and easing symptoms of menopause.

"It's not a huge taste treat, but it sure is good stuff," says Carlson.

Tinctures are easily compounded into remedies comprising multiple herbs, including some that make the primary ingredient more effective, says Carlson. One of those supportive plants is ginger, which Carlson recommends in tincture form to quickly alleviate nausea. The herbalist used ginger to demonstrate the tincture-making process in a June workshop open to the public.

"It's satisfying, and it's cost-effective," says Carlson, noting that tinctures often cost $10 per ounce in a store but can be made at home for as little as $1.50 per ounce.

"The plants are free if you pick 'em yourself," he adds.

Pharmaceutical-grade alcohol from corn or grapes costs about $100 per gallon if purchased from the certified-organic microdistillery Alchemical Solutions in Ashland. Smaller quantities can be purchased at herb shops, along with brown, glass apothecary bottles. Or old tincture bottles can be washed and reused, says Carlson.

Recycling isn't the only eco-conscious aspect of making tinctures, he adds. There are many more therapeutic doses in a tincture than a dried-herb tea.

"They're incredibly resource-efficient," says Carlson. "There's ecological value to making tinctures."