When it comes to growing perennial crops in a time of climate uncertainty, water (or lack thereof) is the first thing that generally comes to mind. But some climate effects can have a significant impact even when water is plentiful—for example, chill hours. All temperate fruits go dormant during cold winter months, and each requires a certain number of hours during this dormancy where the temperature sits between 32°F and 45°F. Too few chill hours and the tree or vine will neither bloom nor set fruit properly, resulting in a spotty crop at best. Grapes, having been domesticated in relatively warmer climes, on average require 90 or so chill hours. But apples, whose origins stretch back to the cool mountains of Central Asia, need anywhere from 400 to more than 1,000 chill hours to ensure they break dormancy properly.
Chill issues present a larger problem in somewhat balmier parts of the world, such as California, but as global temperatures continue to rise, the number of chill hours will start to decrease pretty much everywhere. Studies done in the United Kingdom have already demonstrated a steady decrease in chill hours since the 1960s. And warming winters aren’t the only issue. Unusually high temperatures during a fruit’s ripening period can have a considerable impact on flavor as the excess heat disrupts the balance of sugars, acids, and various aroma compounds we’ve come to associate with our favorite varieties. Lower acid levels, in particular, can make ciders and wines a little flabby and flat tasting, even if the boost in sugars does pump up the potential alcohol.
The northern parts of the United States have a different set of problems—principally, unseasonably warm spells in February and March that coax tender buds to begin to swell in anticipation of spring. When icy winter weather inevitably returns, those buds sustain irreparable damage resulting in significant fruit losses. This phenomena is occurring with increasing frequency, most recently in 2016, when some apple growers in the northeast reported lost as much as 80 percent of their crop. Techniques such as using heaters or water sprays, though costly, can mitigate this damage to a certain extent, but not in the face of sudden, radical temperature plunges.
The wine world has seen some of these problems coming for years and has been mounting efforts to help protect itself by either considering lesser-known grape varieties with better performance in the heat or by breeding new ones (see “Popeluchem: Breeding winegrape magic on California’s central coast”). The cider industry is just starting to take off, however, and though apple-breeding programs have existed for some time, with the exception of a handful of programs in Europe, their focus has been on new dessert/market apples and disease-resistant rootstocks. Now that cider has emerged as a viable and growing market in North America, apple breeders such as Dr. Susan Brown at Cornell University in Ithaca, N.Y., and Dr. Kate Evans at Washington State University in Pullman, Wash. (pictured above), are expanding their focus to include apple varieties whose primary purpose is use in cidermaking—that is, apples with much higher levels of bitter and astringent tannins than are found in market varieties.
Old-fashioned apple breeding is a time-consuming process, though. It takes an average of 16 years from the time a cross is made to when an apple has been evaluated sufficiently to determine if it’s commercially viable. This lead time may drop as modern DNA analytical techniques help scientists better understand which parts of an apple’s highly complex genome confer the properties sought by cidermakers, which would allow breeders to make more thoughtful choices regarding parent apples. Parental selection is likely to be increasingly important, as a recent study determined that more than 60 percent of the dominant market apple varieties derive from a mere five cultivars.
One apple expert, Dan Bussey, manager of the Heritage Orchard of the Seed Savers Exchange in Decorah, Iowa, and author of the soon-to-be-released The Illustrated History of Apples in North America (JakKaw Press), estimates there have been some 20,000 named apples grown on this continent since 1620. Only 4,000 or so are still available in privately owned and government-sponsored collections around the country, but these could surely provide a more diverse set of parental possibilities. Indeed, one or more of these old and largely forgotten apples might prove to be a perfect candidate. Kuffle Creek Nursery in Riverside, Calif., which specializes in apples for warmer areas, has begun evaluating more of these old varieties for their low chill potential.
A more time honored, and possibly haphazard, approach is the one followed by John Chapman (aka Johnny Appleseed). The apple genome is large and complex—so much so that any one seed may or may not bear a resemblance to its parents, which is why apples, like grapes, are propagated by grafting. In the 19th century, Mr. Chapman collected bags of seeds from eastern cider mills and strewed them across the western frontier. Some modern day American cidermakers are doing much the same.
Eleanor and Albert Leger of Eden Specialty Ciders in Newport, Vt., have sown hundreds of seeds gleaned from their spent pomace, and anything that survives their harsh northern Vermont winter is deemed worthy of transplanting to their orchard for further study. So far, three have made it. Others, such as Eric Johnson of the Widespread Malus Project in Boulder, Colo., have been planting wild apple seed ordered from the U.S. Department of Agriculture’s Agricultural Research Service in Geneva, N.Y. The parent trees were grown from seeds collected in the 1980s in Kazakhstan, the apple’s ancestral home, and, while significantly related to our modern domesticated apples, are a distinct species.
The possibilities of these smaller projects are promising, but it’s still sobering to note it took 30 years from the time the seed was planted for Honeycrisp to become available commercially. A handful of cidermakers don’t want to wait that long, so they’re taking an alternate approach. There are feral apples in any number of the wild places of America, the seeds of random parent trees sown by cattle and deer over the last 150 years. A handful of intrepid and impatient cidermaker/orchardists have been seeking out these wildings, and since they’re already old enough to bear fruit, first-level selections can be made more or less on the spot. Any wild tree with fruit that shows no signs of disease is a good candidate.
Two such fruit explorers can be found in the wilds of New York. Andy Brennan of Aaron Burr Cidery (Wurtsboro, N.Y.), uses flavor as his primary selection criteria, with an emphasis on acid and tannin, but also pays particular attention to apples that ripen later in the season, because they’re likely to be late bloomers and thus escape the risk of bud-killing frosts.
Eric Shatt, cidermaker and orchardist at Redbyrd Orchard Cider (Trumansburg, N.Y.) as well as Cornell University’s orchard manager, looks for wildings with late bud development and blooms in addition to outstanding flavor. He’s been testing several good candidates in his Finger Lakes orchard for the last several years, three of which are now available on a limited basis through Cummins Nursery, one of New York’s best-known commercial apple nurseries.
Both Brennan and Schatt have provided grafting wood to a select number of orchards around the country, so these promising varieties can be evaluated under diverse growing conditions.
All of the approaches detailed here have the potential to create new apples that can help the modern American cider category grow to its full potential while still addressing our fluctuating climate. In the end, there won’t be just one solution, but many—and they’re likely to be as varied as American cider itself.