Plus, how they affect the wine they're aging.

By Jonathan Cristaldi
September 25, 2018
Courtesy of Progeny Winery

Whether you've ever visited a winery and embarked on a tour, or just seen them the movies, if someone says the word winemaking to you, you might conjur up an image of a massive cellar holding stacks upon stacks of large oak barrels. Or maybe it's a room filled with rows and rows of tall, flashy stainless steel tanks. But if this magazine's recent foray into Georgian wine has taught us anything, it's that winemaking doesn't have to take place in a traditional barrel or tank. (In Georgia, they ferment and age wine in beeswax-lined earthenware jars called qvevris.)

Step inside some of California's most progressive wineries these days, and you'll see concrete tanks instead of stainless, in unusual shapes at that. More than a few have taken cues from at least two of France’s greatest producers—Château Petrus in Pomerol and Cheval Blanc in Saint-Émilion—which rely on concrete vessels to produce some of the most renowned wines in the world.

Why concrete? For the most part, these tanks are used during the fermentation process, and winemakers love them for their microporosity. Stainless steel won’t impart any flavor or oxygen, while brand new oak barrels will impart lots of flavor and allow for a great deal of oxygen exchange. Concrete is somewhere in the middle—allowing for extremely slow, trace amounts of oxygen exchange. According to some winemakers, concrete will even impart a kind of mineral element in wine. This last point is extremely controversial, however, as many winemakers say there’s no exchange, especially if concrete is lined with an epoxy. They attribute any mineral overtones, or bright aromatics, to the wine’s mouthfeel and the natural flavors shining more from grapes, all thanks to concerete’s neutral impact.

As far as an investment is concerned, concrete isn’t cheap. Steve Rosenblatt, president of Sonoma Cast Stone, which has designed and built tanks for many wineries in Napa and Sonoma, explained that something like the increasingly popular concrete egg tank, which takes roughly 16 weeks to produce, can cost as much as $120,000. That’s because concrete eggs often start out as drawings, are then 3D printed, perfected, and turned into heavy-duty styrofoam and fiberglass molds. Once a mold is designed, subsequent eggs can be produced for roughly $10,000 to $14,000 each. It should all give you a little perspective on the price label of that $50 price tag—or more— on that wine list.

Whether it's oak, concrete or something else entirely, alternative wine tanks are a sight to behold—to say something nothing of the wine they produce. Below are 11 of some of the coolest tanks out there, complete with descriptions of how they impact the wine. 

1. Concrete Tanks at Rudd Oakville Estate (Napa Valley)

Matt Morris

For the new tanks at Rudd Oakville Estate, winemaker Frederick Ammons tapped the same mason who designed the tanks at Château Petrus in Bordeaux. Poured in four stages—the foundation and legs, the floors, walls, and the roof—that each take nearly a month, the concrete is a mixture of filtered well-water and some 60 tons of rocks, culled from their own vineyard. “We feel there’s a real continuity of our terroir,” says Ammons. “It won’t exactly impart flavors, but this is part of the philosophy. The tanks are so massive and heavy themselves that even as fermentation goes on, you don’t have to cool the tanks like you do with stainless steel. So you have a more natural fermentation, and maybe longer fermentations, and that lends more textural and more aromatic notes than you get from stainless steel aging and fermenting. Like a used barrel, concrete imparts certain notes. There’s yeast from previous fermentations and other things, which is part of the magic of an older cellar.”

2. Clay Amphoras at Saxum Vineyards (Paso Robles)

Ron Bez

In similar fashion to Rudd, winemaker Justin Smith of Saxum has taken “terroir taste to its farthest extreme,” according to Travis Simmons of Sonoma Cast Stone, which crafted Saxum’s concrete eggs. “He dug out caves on his property and sent us the rocks. We pulverized the rock and made the concrete tanks, which were in an amphora style.” Glycol temperature control systems—the same ones that grace stainless steel tanks—are “embedded in the concrete walls of the Amphorae, so it’s not in with the wine,” Simmons says, “so there are also no hot or cold s because it’s embedded, rather than wrapped around the tank.” The egg shape is important because there are no corners or pockets for the fermenting wine to stagnate in. Amphoras help keep the caps (the crushed grape skins that float to the top of the tank if fermented together with the juice) submerged, allowing for less manual punchdowns.

3. Reverse Egg at Progeny (Napa Valley)