Winemakers Heated About Fermentation
When I made some calls, one early interviewee was Brendan Eliason, owner/winemaker at Periscope Cellars in Alameda, Calif., one of the growing gaggle of urban warehouse wineries in the San Francisco Bay Area. Besides expressing his own druthers, he noted, "This is a weird topic. Every winemaker I know makes the same argument, that they get better color and better fruit from whatever temperature they happen to prefer."
Sure enough, winemakers are all over the thermal map. Could they all be right?
There's plenty of science demonstrating that lower temperatures do a better job of preserving elusive aromatic and fruity esters, which is why white wine fermentations, especially for the aromatic varieties, are generally kept quite low. On the other hand, higher heat increases phenolic extraction rates, especially in the presence of ethanol--at least up to the point where the yeasts are fried. But it's hard to find much literature on the precise effect of five degrees in either direction, a level of detail complicated by differences between batches of fruit, varietal characteristics and wine style preferences.
Corison aims for a combination of power and elegance, and to get there, her practice is to get the temperature up into the high 80ºsF early on, by mid-fermentation, and then let it fall. She needs the heat for extraction, but wants that to happen early, in a low-ethanol environment, to minimize extraction of harsher, more bitter phenolics at the end. "I don't believe we can surgically remove nasty tannins later on, by fining or whatever," she says. Getting color in the Rutherford Bench, she notes, isn't really a problem.
Like everyone I talked to, Oregon Pinot Noir specialist Luisa Ponzi says temperature management can be critical for achieving an intended wine style. For the Ponzi Pinots, she aims to get her high temperatures early: a maximum of 90º by the time the wine gets down to 15ºBrix, and she's happy with the high 80s. This approach means most extraction happens at low alcohol levels. But for the winery's Dolcetto, where highlighting the fruit is key, lower temperatures are in order.
Kelly Urbanik, winemaker at Bedell Cellars on Long Island, N.Y., follows a similar, two-temperature protocol. For the winery's Merlot, its meat and potatoes wine, Urbanik aims for a 90º peak at about 15º Brix, then tapers off. It's the same logic: maximum extraction at low ethanol. For her Cabernet Franc, on the other hand, she keeps the temperature down below 80º. The goal is a lighter-style wine, and since the Franc isn't as deeply colored anyway, there's no point in cooking the wine to try and extract more. Even some Merlot lots, from blocks that have proven to be lighter in the past, get the cooler treatment.
At Napa's PlumpJack, winemaker Tony Biagi pu rsues a modernist variant of the high temperature approach for the Cabernets. For most batches of fruit, he likes 85º-88º; but for others, like early-picked grapes with tougher, more recalcitrant skins, he's fine with cranking the temperature up near 100º. If the goal for a particular fermentation is color and fruit, he peaks his temperatures early; for tannin, later on.
Like Ponzi and Urbanik, Brendan Eliason tries to get his reds--a wide spread of varieties--to crest at 90º, by about 10º Brix remaining, then gradually cool down. Most of his fermentations are done in 1-ton lots in bins, the right thermal mass to get to his desired temperature and not higher. He uses Pris de Mousse / EC 1118 as his house yeast, with a strategy of getting the fermentation hot and getting it over with, fast. His few experiments with lower temperatures and slower fermentations have given him concerns about spoilage issues.
David Coffaro--of David Coffaro Vineyards in Sonoma, where Eliason learned his trade--is known for doing things his own way. He recognizes that all the books suggest temperatures in the mid-80s, but what he wants is something more like 90-92º. Within reason, he thinks, more heat will get you more flavors, and perhaps blow off some excess alcohol to help wines develop more quickly in barrel. A decade ago, he bought several 4-ton fermenters and discovered they let things get too hot; he then had 1-ton boxes custom-built as replacements.
When I called, he was worrying about one lot that had hit 95º with 6º Brix left to go. He was putting in buckets of ice from the freezer to coax it down--not an everyday procedure, just an indication that winemakers will do what they have to do. Coffaro, who has worked with dozens of varieties over the years, has also observed that juicier varieties--Barbera, Zinfandel--tend to ferment hotter than less juicy varieties, such as Cabernet.
And by the way, his most recent fermentation experiment is putting wine through malolactic before alcoholic conversion--but that's another article.
Some like it cooler
Now to Julie Lumgair, where this whole track started. Different years, different varieties and different batches of fruit can require different treatment, but she does have a general routine for most reds. Fruit is cooled down to 55º at the crush pad and put through a seven-day cold soak at that temperature. After yeast addition, the temperature moves gradually up to a high of 80º. Lumgair uses yeasts that do their work fairly slowly--Asmanhausen for Pinot Noir, for example--believing that the pace is critical. "Radical Brix drops," she says, "stress the yeast and increase the chances of sticking at the end."
At Provenance Vineyards in St. Helena, Calif., Tom Rinaldi also likes the 80º range for Bordeaux varieties. Warmer than that, he says, and you can start losing control, as well as blowing off desirable esters. In the high 70ºs rather than the high 80s, the resulting wines seem more plush and just as well extracted. Slowing the fermentation down means more time for extraction at the critical midpoint. In a perfect world, Rinaldi would want to maintain that relative warmth through to the end of the fermentation, to ensure it goes dry.
Rinaldi also raises another important point: knowing what the temperature of a fermentation really is. With this harvest, Provenance has been using a new tank probe with five sensors at various heights, all translated into color on a screen, and the variations that show up, he says, are amazing. The technology allows for gauging how well a pumpover succeeds in mixing the tank, and also for determining the optimum timing and frequency of pumpovers.
Julie Johnson at Tres Sabores in Napa was the first of my sources to mention the merits of multiple temperature ranges, but certainly not the last. For her estate Cabernet, she follows the orthodox path, getting temperatures into the high 80ºs or low 90ºs. For her Zinfandel, however, Johnson has drawn some lessons from an initial stage of the winery, in which she had three different winemakers working with the fruit, which grows up a slope on the property.
From bottom to top, different sections would be harvested as they ripened, and then go to their respective winemakers. Johnson makes her own Zinfandel now, but from the earlier experience, she ferments different lots at different temperatures, including some--from the topmost vines--in the mid-70s, getting distinctive flavors of blueberries, sarsaparilla and spice that add complexity to the final blend. For a small winery--eight acres of Zinfandel--doing mini-fermentations, controlling temperature involves everything from wrapping bins in insulation to keep them warm to rolling them outside at night to cool off the cap.
Bryan Harrington, another of the Bay Area upstarts with a winery facility in San Francisco, also finds value in multiple temperature fermentations for his Pinot Noirs. Without refrigeration or much heating capacity, Harrington tries to take advantage of the different temperatures reached in different fermentation vessels--some relatively cool at 80º, some considerably higher. "In the bigger bins," he says, "I can get to 100º, but I don't want to!" Lower-temperature lots add aromatics and freshness, higher-temperature lots depth, richness, and earthiness.
By far my coolest informant--coolest temperature, that is--was Jon McPherson at South Coast Winery in Temecula, Calif. The basic routine for the winery's range of Rhône and Bordeaux reds starts with crushing the fruit and then holding its temperature down--in the low 50s--in tanks for a couple days, to make sure the winemakers have accurate numbers and can make appropriate additions. Then the lots are inoculated with yeast, and the temperature slowly rises, maybe two degrees per day, so that by the end of the first week, the temperature is in the low 70s, where it stays--sometimes getting a few degrees higher--until pressing just before dryness.
The cold soak and the cool temperatures, McPherson says, get out all the water-extractable tannins he needs. Using a tannin assay and monitoring color, he has learned that the most significant changes and extractions happen in the first six or eight days. The wines all end up in barrel for anywhere from 10 to 18 months. McPherson acknowledges that this regimen makes for wines that are softer but still rich and, he thinks, ageworthy. Since South Coast was named "best winery" in California at the State Fair this summer, it must be doing something right.
So, in summary, the answer to my original question--Can the many different theories about red wine fermentation temperature all somehow be true?--is a resounding, "Yes."
Tim Patterson writes about wine and makes his own in Berkeley, Calif. Years of experience as a journalist, combined with a contrarian streak, make him interested in getting to the bottom of wine stories, casting a critical eye on conventional wisdom in the process. He may be contacted through email@example.com.