There’s a lot about making beverages that seems a little bit magical. Add a dash of yeast to humble ingredients like grain or fruit, wait a few weeks (or months, even years) and presto: you’ve created something with the potential to transport, inspire and astound.

Of course, most of us have an inkling the process is more complicated than that. The people who make your favorite drinks spend a lot of time focusing on such decidedly un-magical things as organic chemistry, fluid dynamics and standardized sensory evaluation panels. But for cidermakers, keeving — a technique used by European makers to slow down fermentations and produce sweeter, more flavorful ciders — still inspires the bright eyes and hushed tones of witnesses of a minor miracle.

“Keeved ciders are difficult and incredible,” says Angie Watkins, cidermaker at Cider Riot! in Portland. Watkins and several other Northwest cidermakers recently returned from a USDA Specialty Crop Grant-funded trip to Normandy and Brittany, France, to learn more about keeving.

“There are no other ciders with more of a sense of place,” she says, adding that the incorporation of keeving could have the potential to differentiate regional ciders in the Northwest and elsewhere.

The process can take anywhere from a few days to a couple of weeks, and it requires a few things: cool temperatures, low-nitrogen fruit and a juice pH between 3.5 and 3.7. To start, cidermakers add an enzyme that causes the pectin in the juice to bind to itself, creating a mass called a chapeau brun (“brown hat”). Then, the juice is fermented very, very slowly, at a temperature just warm enough to keep the yeast cells alive. The carbon dioxide generated by this tortured yeast slowly raises that chapeau brun to the top of the tank, protecting the fermenting cider from oxidation and indicating a successful keeve.

At this point, the yeast has been so weakened by a high pH and low temperature that fermentation practically grinds to a halt, even though there is still a bit of residual sugar left. The cider is racked off from below the chapeau brun and, in the most traditional settings, bottled and allowed to naturally carbonate in its packaging without fear of excessive secondary fermentation. The entire process is labor-intensive, finicky and somewhat unpredictable even for the most seasoned cidermaker, but it produces cider with a natural clarity and sweetness that can’t be replicated any other way.

Nobody knows exactly how the technique originated, but in Europe, it serves a critical purpose by allowing cidermakers to produce sweet ciders without back-sweetening, which is not allowed under European Union regulations. In the U.S., cidermakers are free to use back-sweetening, but there’s another reason to use keeving: the preservation of fruit aromas.

Kevin Zielinski, owner and cidermaker at E.Z. Orchards in Salem, Oregon, is one of the only Northwest producers to use keeving on a regular basis. He says its ability to preserve fruit’s natural aromatics is one of keeving’s most underrated qualities. “The slow ferment retains aromatics because you don’t get that aggressive CO2 scrubbing,” he says. “You don’t get the aggressive ferment and, because the fermentation is protracted over a long period of time, you get a slower development of texture and aromatics.”

This fall, Watkins is already planning her first keeving project, a French-style cider made from cider apples grown in nearby Yamhill, Oregon, and the odds are good several other Northwest cidermakers who went to France have their own plans in the works. “It’s kind of a gamble,” she says. “A failed keeve can spoil.” But success, if it comes, will surely be sweet.

This article originally ran in the fall 2017 print issue of Sip Northwest. For the full story and more, click here