Farm-to-table sourcing is downright tame compared with what some distillers and bartenders are doing to source spirited ingredients. They're foraging for wild-grown plants in local parks, fields and forests.
"There are some weeds that you suddenly find value in when you can do something with them," cocktail historian Jared Brown of Mixellany, told attendees at a Tales of the Cocktail seminar Friday on homemade cocktail components. Dandelion wine? Blecht, he ruled. But a homemade dandelion cordial was delightful.
More of the finds are less noticeable plants—yet, ones you probably pass by every day. To find them, CNBC tagged along on a foraging tour earlier this month that importer Frederick Wildman and Sons organized for local bartenders in Brooklyn's Prospect Park. Barely off the sidewalk, forager "Wildman" Steve Brill, who has been leading NYC-area tours for more than 30 years, was already pointing out several varieties of edible plants—including several in the mustard family, and a relative to spinach—growing like weeds (which they are) along the path.
(What did we find—and make cocktail-worthy? Check out the video above.)
"If these things are working in Prospect Park, why couldn't they work on 19th Street?" said Ann Marie Del Bello, beverage manager at ABC Cocina in New York City, who collected spicy Poor Man's Pepper for possible planting in the restaurant group's rooftop garden. The plant's bite might work well with gin and Chartreuse in "herby" drinks, she said.
Foraging fits a number of broader cocktail trends. It gives bartenders an edge on unique ingredients, and a cool story to go along with them—especially if the ingredient in question has a role in folk remedies or herbal medicine.
"It's interesting to find plants that other bartenders aren't using or don't know about," Stilo Pimentel of Sweetwater Social in New York City, told CNBC on the tour.
It's also a sustainable effort in farm-to-table venues. "There's no reason you shouldn't have farm-to-glass, too," said Tim Master, a brand ambassador for Frederick Wildman and Sons.
Master, who is now in his second year of organizing bartender foraging tours for the brand, came up with the idea while visiting monks who make herbal liqueur Chartreuse. "[The father] started picking things in the garden, saying 'This is in Chartreuse, and this,'" Master said. "I thought, why not show bartenders what they walk by every day on their way to work?"
Strain foraging infusion (we had sassafras and wood sorrel in a little hot water) and muddle together with sugar and grapefruit peel. (Use 1:1 ratio of liquid to sugar.) Mix 0.25 oz. of the resulting syrup in a shaker with the lemon juice, gin and Chartreuse. Add ice and shake together. Strain into a highball glass over ice. Top with sparkling water. Garnish with more grapefruit peel.
For craft producers, foraging can be more essential, as both a cost saver and a way to source their most unusual required ingredients. "That equals a free ingredient, of the highest possible quality and sustainably sourced," said Bianca Miraglia, the founder of Uncouth Vermouth in Brooklyn, who makes a rotating selection of seasonal vermouth. Her most valuable find: Mugwort, which goes into all her vermouth. "That's really important for me, and really fortunate that I can find it and not have to buy it," she said.
"It's a weed," said Miraglia, who has a background in winemaking, and learned plant lore as a child while hiking with her parents. "It would be like buying dandelions."
Simon Buly, gin master for Caorunn Gin in Scotland, collects heather, bog myrtle and dandelion, among other finds, all of which go into the gin. "Luckily, they all grow within 10 minutes of my office," he said. The area is remote, with only a few livestock farmers. "It's as wild as you're going to get in this day and age."
Of course, there are some practical concerns for bartenders—and their customers—to be aware of. Foraged finds may fall into a grey area of local restaurant health codes.
"Food should always be from approved sources," said Leon Lubarsky, a principal with Letter Grade Consulting in New York City. Generally, that's not the local park. The potential risk for consumers is, an inspector might not spot a problematic ingredient, since sourcing tags aren't required for produce as they are for say, shellfish. "I wouldn't know how a health inspector would know where something was picked," he said.
Distilled products are held to higher standards. Distillers must obtain federal approval before sale. "I have to send in a formula and a sample to the federal laboratory," said Miraglia. Any problems—such as the inclusion of an inedible plant or pesticide residue—would result in a rejection.
It's on would-be foragers to educate themselves. "Your first word of warning is: Go buy a book, take a tour," Mixellany's Anastasia Miller said. Some poisonous berries look similar to edible ones, for example, and even edible plants have some inedible parts. It's important to be sure you know what you're picking.
"Start with a small number of plants that are easy to recognize and don't have any poisonous look-alikes," said Brill, who has a Wild Edibles app with some of the easier finds.
Avoid picking in areas that may have been sprayed with pesticides, or are within 50 feet of traffic, he said. Be mindful of local regulations that may limit what (if anything) you can pick. "The important thing is that you do no harm to the environment," said Brill.
CNBC.com is in New Orleans for the 12th annual Tales of the Cocktail festival, which runs through Sunday. Check back for more coverage of the trends shaping what you'll drink at home and on the town—and how much you'll spend doing so.
—By CNBC's Kelli B. Grant