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Column Article from the February 2010 Magazine Issue
With Fermenters, Does Size Matter?
Quick now, summon up an image of a small fermentation vessel; what probably comes to mind is a little old (or earnest young) winemaker, doing a hand punch-down, eagerly trying to tease some terroir out of the fruit. Think big fermenter, and you’re likely to envision a gleaming tank farm producing boatloads of generic wine. Garagistes, after all, do not operate in public parking garages. It seems impossible to do great wine on a grand scale, but why?
The actions and reactions that go on during fermentation are molecule on molecule, or microbes devouring molecules and emitting altered molecules. Why would scale matter? Assuming control of temperature, oxygen and a couple other things, why would a big tank under-perform a small one?
Maybe this is just more winemaking ideology. Maybe it’s just another example of how the Pinot Noir gang, who would make wine a bottle at a time if they could, have projected themselves onto the whole wine world. Or maybe there’s something to it.
The Pessagno paradox
I’ve always thought smaller would be better -- I mean, as a home winemaker who relies on 30-gallon food-grade trash cans wrapped in electric blankets, of course I have. Then I happened to be yakking with Steve Pessagno, the longtime winemaker at Lockwood who now is running his own label in Monterey, about the prevalence of winemaking myths and half-truths, and he recounted an experiment he did 15 years ago at Lockwood.
As he recalls, he was talking to Leo McCloskey of Enologix, the Santa Rosa-based premium wine-consulting firm, and McCloskey insisted that high-quality red wine could only come out of small fermenters. Pessagno, trained as an engineer and not good at taking things on faith, couldn’t figure out why that would be true. So he rigged up a side-by-side test: two fermenters, same height-to-diameter ratio; one getting about 14 tons of Cabernet Sauvignon, the other about 105 tons of the same fruit; inoculation with the same commercial yeast; an elaborate system of temperature probes and controls to ensure equivalence; similar pump-over regimes, with the times adjusted to the size of the caps; and so on.
When the wines were done, they were run through the battery of Enologix analytical tests, coming up with composite index numbers for style and quality. Sure enough, the big tank won -- just barely, but it won. This left Pessagno with a big smile on his face, and a very big fermenter’s worth of really good wine.
McCloskey doesn’t remember the experiment in as much detail, but he is convinced that winemakers, especially in California, tend to make decisions about fermenter size and other equipment “out of thin air.” He’s critical of the chief academic advisers to the wine industry, like the faculties at the University of California, Davis, and California State University, Fresno, for emphasizing the science of fermentation and neglecting the importance of engineering -- something he says is strongly emphasized at, for example, the University of Bordeaux. This is one important reason why he thinks the French are so much better at making ultra-premium, highly-rated wine on a much larger scale -- the 40,000 cases coming from Château Lafitte-Rothschild every year, compared to the California producers in the same market segment that are lucky to turn out 2,000 cases.
Practical matters
There’s clearly more to ramping up wine scale than fermenter size, and also more to fermenter size choices than just ideological stance. Even if we accept the implication of Steve Pessagno’s little experiment -- that if you somehow hold all the fermentation variables constant, big fermenters work as well as small ones -- there are still a passel of practical reasons why holding all those things constant is somewhere between difficult and irrelevant.
Winemaker Alison Crowe oversees an elaborate custom-crush operation for Plata Wine Partners, spending time each harvest in 12 different crush facilities, with 12 cellar crews and fruit coming in from 1,200 acres farmed by Plata’s parent, UCC Vineyards. Let’s just say she deals with a lot of fermenters.
“Theoretically,” she says, “there’s no reason sheer tank size should matter. But in practicality, big tanks are harder to chill, to heat, use more energy, and need a higher jacket-to-volume ratio. Once you scale up, you have to scale up everything -- jackets, oxygen, measuring -- to make sure you know what’s going on; lots of little things. If your crew is used to doing 5-ton fermentations, the moment you bring in a 50-ton fermenter, you need a whole new set of procedures.”
One of the most important considerations is oxygen access and its close relative, redox potential. This is a prime reason why veteran Pinot winemaker Larry Brooks, now at Tolosa in San Luis Obispo, Calif., has a decided preference for smaller (4-ton range) fermenters with open tops. “The hardest thing to control in a big fermentation,” he says, “is oxygen, and smaller fermenters almost automatically get more oxygen.”
Punch-downs add to the oxygen supply. Brooks uses an analogy to barrel size: The reason wine generally gets aged in 60-gallon barrels -- not larger and therefore cheaper containers -- is the rate of oxygen intake. Virginia Tech’s Bruce Zoecklein makes the same point with a different analogy: 5-gallon carboys provide more oxygen pickup than 5,000-gallon fermenters because of the radically different surface area-to-volume ratios.
Next comes temperature, particularly temperature inside the cap and in hot spots that can develop anywhere inside the fermenter. Here issues can arise with both large fermenters, which can generate runaway heat spikes very quickly, and very small ones, which may have trouble warming to the task. Damian Parker at Joseph Phelps says he’s constantly talking to winemakers who do their fermentations in T-bins and find keeping the heat up to be a logistical nightmare. (Interestingly enough, the only difference between Steve Pessagno’s two fermentations was that the smaller tank cooled down a little more quickly at the end of fermentation, and the tank jackets only allowed for cooling, not heating.)
Cap management is generally simpler with smaller fermenters: thinner caps mean easier irrigation in pump-overs, e asier punch-downs and fewer opportunities for embedded hot spots. Thorough mixing in large fermenters can certainly be done; it just takes more work.
Rod Ferronato, owner of Santa Rosa Stainless Steel, says that very few fermentation and storage tank purchases are simple, off-the-shelf buys; most are custom orders, one way or another.
Joseph Phelps Vineyards and its flagship Insignia blend are prominent exceptions to Leo McCloskey’s observation about the relatively small scale of California ultra-premium production. Phelps puts out 10,000-16,000 cases of Insignia every year, listing for $200 per bottle (and has been one of McCloskey’s Enologix clients).
Damian Parker says, “It’s not the tank, it’s what you do with what’s in the tank.” But at the same time, Phelps does have some custom features in its fermenters, like jacketing on the floor as well as the side wall to speed up heating and chilling, and utilizes a great deal of automation, allowing for pump-overs to be scheduled for 3 a.m., while the cellar staff is sound asleep.
Fruit character and wine character
A key element in Steve Pessagno’s Cabernet trial was a common fruit source, with lots from a single vineyard randomly assigned to the two fermenters as they arrived. It added up to something like 120 tons -- Lockwood’s idea of a “small” fermenter wasn’t really all that small -- and plenty of wineries don’t try to handle that much fruit as a single batch. These days, with his own high-end label and vineyard-designated reds and whites, Pessagno has no use for giant fermenters either.
Paul Draper at Ridge Vineyards says that Ridge tries to fit the fermenter to the size of the parcel being harvested -- a portion of a particular vineyard that comes ripe at the same time. The Ridge facilities have several sizes available -- all of them small by Lockwood standards, not because of some philosophy of tanks, but rather a philosophy geared toward careful parcel picking.
The Ridge Monte Bello Cabernet ripens in patches of maybe 1- to 5-tons, and the same is true for some portions of the Zinfandel harvest from Lytton Springs and Geyserville. The Dusi Ranch vineyard in Paso Robles, on the other hand, is more rolling than ridge-y, so its lots of Zinfandel tend to be routed to larger fermenters.
The array of relatively small fermenters offers more chance for control and probably better extraction, Draper believes. He adds an interesting historical observation: The current fondness for small fermenters is partly a reaction to the early days of California winemaking, when huge vessels produced uneven fermentations and poor extraction.
Back in Pinot-land, Larry Brooks thinks that even if small fermenters don’t automatically make better wines, they do make more distinctive wines. “If I have enough fruit, all of it terrific, for 3,000 cases of wine,” he says, “I’d much rather make six 500-case lots than one 3,000-case wine.”
He acknowledges that during one harvest when he was making wine at Paraiso in Monterey, most of the Pinot was made in 4- and 9-ton open-top fermenters -- but the best wine of the vintage was made in a 20-ton closed-top tank.
Alison Crowe says that while Pinot purists contend that open-top is the only way, her custom-crush customers often end up preferring the wine made in static-top tanks. Damian Parker notes that the components of Insignia in recent years have been made in everything from 4- to 8.5- to 12- to 21-ton fermenters.
So where does this leave us? Does size matter? Sounds like you can make very good wine (and also bad wine) in many sizes of fermenters.
Winemakers determined to put their personal stamp on wines will probably always tend toward smaller fermenters in hopes of exerting more control. And just in case, it’s better to have a lot of options in your cellar, since the harvest gods could not care less about your tank philosophy.
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. Contact him through edit@winesandvines.com.
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