Vineyard & Winery Management Magazine
Feature Story
Concrete Tanks Make a ComebackWinemakers explore alternatives to stainless steel and oak
By Larry Walker
In the rush to modernize wine production in the 1960s, stainless steel tanks for wine storage and fermentation became the vessels of choice for most winemakers. Old wooden uprights, whether of oak or redwood, were abandoned or became tasting room curiosities. Concrete tanks and vats also went into the enological trash heap.
Recently, winemakers have been taking a fresh look at concrete tanks, some thinking that perhaps they threw out the baby with the bath water. Maybe there was something to be said for a winemaking tool that had been used for centuries and is still fairly common in Europe and parts of South America.
Charles Thomas, now director of vineyards and winemaking at Quintessa in Napa Valley, is a modern-day concrete tank pioneer in California. He first used them in 2003, when he was the winemaker at Rudd Vineyards & Winery in Napa Valley.
"In the 1970s and 1980s in California, concrete tanks were associated with larger and older wineries, mostly producing inexpensive wines." Thomas said. "In a winemaking era that valued modern technology, concrete tanks were decidedly low-tech and out of fashion. But I remember visiting several of these wineries in the very early 1980s, including Brad Alderson at Robert Mondavi Woodbridge (now Woodbridge by Robert Mondavi), and remarking how fiercely loyal the winemakers were to their large open-top concrete red fermentation tanks."
Thomas also visited many cellars in Burgundy and Bordeaux, and realized that some of the world's great wines were being fermented in small (800- to 2,000- gallon) concrete tanks.
"In 2002 when I started at Rudd Winery, we were deciding how to replace some older stainless tanks in part of the original cellar," Thomas recalled. "On a scouting trip in France and Spain, I spoke with a number of winemakers who had experience with concrete, wood and stainless, and I (finally) became convinced enough to seek out the top tank producer in Burgundy - Nomblot - and import some tanks and ‘eggs' for the 2003 harvest. I brought concrete tanks to Quintessa in 2008." Artisan Barrels of Oakland, Calif., supplies the tanks.
At Quintessa, there are seven cement red fermentation tanks ranging from 1,000 to 2,000 gallons, and six 165-gallon egg-shaped concrete vessels, which Thomas uses for sauvignon blanc. He said he expects to add more tanks and eggs in the future.
"For the whites, the slight porosity of the concrete gives the richness of a barrel fermentation, but without the oak," he said. "Fruit aromatics stay pure, but with more complexity than in stainless steel. In the larger tanks, there is a slight ‘micro-aeration' effect similar to what we see in a wood tank. The fermented wine is slightly more accessible than wine fermented in a stainless tank. This slight difference persists through barrel aging."
Another plus for Thomas is taking care of the empty tanks. "A small open-top concrete tank does not require the extensive care that an empty wood tank needs. Wash it, rinse it, and then leave it open," he said.
NEWER CONVERTS
Steve Edmunds of Edmunds St. John winery in Berkeley, Calif., became interested in concrete tanks about 20 years ago while tasting wine in France. In 2009, he got his first concrete tank, from Vino Vessel in Paso Robles, Calif. (he also represents the company).
"Pluses include temperature control, no taste of wood obscuring fruit character and no reductive tendencies, which I have found in stainless," he said. "The wine is naked in concrete, so the fruit needs to be really good."
Edmunds cured the concrete using a 30% tartaric acid solution until there was no further reaction between the acid and the calcium in the concrete. This was followed by a water rinse. "Concrete won't do well with water above about 108°F, and pressure washing will wreck the surface, so cleaning needs to be done with consideration for those issues," he said. "When the tank is empty, it's important to let the inside dry thoroughly, giving it plenty of ventilation to prevent any possibility of mold."
While some vintners have their concrete tanks lined with epoxy, as in years past, those making higher-end wines today prefer the porous quality of unlined tanks.
Chris Russi, winemaker at Thomas George Estates in Sonoma County's Russian River Valley, said he first became interested in concrete tanks when he worked the vintage in 1997 in the Barossa Valley of Australia.
"There are many concrete tanks in Australia and at the time, a few wineries were rediscovering the benefits of concrete for both fermentation and storage," Russi said. "They claimed the wines had more fruit expression and a greater richness. The down side, though, was the difficulty cleaning. I was working harvest, so it was occasionally my responsibility to clean them - and it wasn't easy. In fact, I think it was the most hated job in the cellar."
Despite that, Russi said he believes the benefit to the wine makes cement worthwhile, and he has ordered four tanks for the 2010 harvest from Sonoma Cast Stone in Glen Ellen, Calif. "I ordered three of the tanks without a bottom door, and I plan on using them for fermentation and storage of chardonnay," he said. "Thomas George Estates now owns three vineyards. My goal is to have a concrete egg of chardonnay from each one." The fourth tank with a cleanout door will be used for pinot noir.
"The concrete eggs will be another tool for us, a breathable tank (like a barrel) with no oak influence," he added.
Sonoma Cast Stone went into production with its 500-gallon, egg-shaped tanks in early 2010. Until then, the "eggs" had only been available from European producers.
Terry Reap, director of winery sales for Sonoma Cast Stone, said the thermodynamics of the oval shape lead to the deposit of the lees across a larger floor area and prevents the need for stirring. The eggs can be ordered with an optional pomace door to make cleaning easier than it was for Russi in Australia.
The interior of the tanks is made from traditional colorless concrete, produced using chlorine-free water, while the outer shell is composed of EarthCrete, which Reap described as "a revolutionary new FiberCast concrete that is both environmentally sustainable and extra strong."
Josh Beckett, winemaker at Peachy Canyon Winery in Paso Robles, used a concrete tank for the first time in 2008. "I find a lot of positives," he said. "The temperature retention is unbelievable and stays very consistent. You don't get extreme spikes. Also, the wine is extremely pure. There are aromas, especially in fermented reds, that I had not noticed before. Also, it is nice to ferment the whites and leave the wine on the lees for as long as you want."
Beckett uses an oval and a larger upright cement tank from Vino Vessel. "The upright allows for good juice-to-skin ratio for punching down and good juice extraction with the reds," he said. "With white wine, you get a convection effect in the oval for self-lees stirring."
Beckett has fermented viognier, grenache blanc, zinfandel and petite sirah in concrete and said he has found no negatives yet. He even found cleanup easy. "Most people, including myself, assume that the tank and its roughness would make it tough to clean, but it really is easy. Rinse out, citric-wash, rinse out, and you're good, as long as your winery is clean and the wines are clean," he said.
INCREASED DEMAND
Micah Utter, president of Vino Vessel, said his company has been making the tanks for four years and business has doubled each year. "And it's going up again this year," he said.
Concrete tanks are somewhat more expensive than stainless - Russi of Thomas George Estates estimated that concrete tanks can cost up to twice as much as stainless - but Utter pointed out that it isn't really fair to do a price comparison. "The concrete tanks contribute to the flavor profile of the wine," he said, "and stainless steel does not."
Vino Vessel makes four tanks: the Pyramid, with a 150-gallon capacity; the Oval, with a 970-gallon capacity; the Hippo, with a 270-gallon capacity, and the Cube, with a 942-gallon capacity. Tanks can also be custom-made, Utter said.
The different shapes add to the winemaker's ability to fine-tune the wine, Edmunds said. "The Pyramid maximizes lees surface for extended contact and therefore more lees influence on flavor," he said. "The Hippo maximizes skin surface in contact with liquid, potentially increasing phenolic character. The larger tanks tend to reduce those kinds of impacts, but are more practical for larger volumes."
Because concrete is porous, there is some concern about contamination from Brettanomyces. However, the winemakers contacted for this article said this was a non-issue, as long as proper procedures are followed to keep the spoilage yeast out of the winery and the tanks are properly cleaned.
MANY TANKS
Alan Viader has used concrete tanks for fermentation for five years at Viader in Napa Valley, including 1,000-gallon cube tanks and smaller egg tanks. The tanks are made by Nomblot in France.
Viader said the tanks have many advantages. "Wines come out brighter and with much higher fruit notes and prettier secondary aromatics that you don't tend to see in wines fermented in stainless," he explained. "Our tanks are 8-feet square and offer a perfect ratio for maximum extraction and surface contact with the cap. They are rated at 6 tons, but on average, I fill them up to 3-5 tons. This makes the cap very thin and easy to punch down by hand. My maceration times are shorter and extraction occurs more quickly because of the surface area."
He has used the tanks for the winery's petit verdot, tempranillo, syrah and smaller cabernet sauvignon lots.
"The fermentations usually start on their own with the native wild yeast sooner in my concrete tanks than in my stainless tanks," Viader added. "Sometimes fermentation starts two to three days into the cold soak, whereas I can go up to eight-plus days in the stainless. Unlike stainless, there is the possibility of having natural yeast hiding in the pores and cracks of the concrete." Those "hidden" yeasts could lead to a jump start for the fermentation.
On the down side, Viader said the tanks can never be cleaned as completely as stainless. "But then again," he said, "neither can wood barrels."
Adding more concrete tanks is definitely in Viader's plans for the future. "I want to focus more on smaller lots and smaller fermentations, and these tanks are the perfect size."
Larry Walker is based in San Francisco, where he writes on wine, spirits and travel, contributing to a number of international consumer and trade publications. His latest book is "The Wines of the Napa Valley," published by Mitchell Beazley.
Comments? Please e-mail us at feedback@vwm-online.com .