Ponzi's fermentations are done with indigenous, natural yeasts, which means they don't always go by the book. Like many of the other winemakers I talked to, she keeps close track of the temperature and applies heating or cooling to the fermentation tanks as needed. But she also remembers that her father, Dick Ponzi, an Oregon pioneer, used to let fermentations just do their thing in open-top bins, which often meant the temperatures got very high, very late in the game. "He made a lot of great wines that way," she says, "and I do a few batches that way every year, too."

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."

With Bordeaux varieties, as well, this cooler regimen helps retain aromatics and enhance a fruit-forward style. She acknowledges that for Windsor Oaks, which is primarily a vineyard operation, putting the best fruit forward is the natural winery complement to selling their grapes.

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.