Winemakers often include technical details in their tasting notes about the fermentation and aging vessels used during the production process, like French oak barrels, concrete vats, or stainless-steel tanks. Fascinating, but what does that mean in the glass?
The winemaking vessel has a surprisingly large impact on a finished wine, mainly depending on the material used to make it. Because stainless steel, oak, concrete, and clay have different properties, each contributes distinctive characteristics to wine. Here’s a look at how they reveal themselves in a wine’s aromas, flavors, and textures.
Much like cooking a steak over a wood-fired grill gives the meat a smoky, caramelized flavor, aging wine in oak barrels imparts woody notes. This may translate to aromas of vanilla and baking spices, or flavors of caramel and toffee. Because wood is porous, barrels allow oxygen to enter the vessel, softening the wine’s tannins and enhancing aromas. Other factors, like the wood’s origin, the age of the barrel, and toast level, also make their mark.
American oak is bolder than European, with prominent vanilla and coconut notes, while French oak is more subtle and spicy. The greater the barrel’s toast level, the more pronounced the oak aromas and flavors in the wine. The amount of time a wine spends in the barrel also matters. Fermentation lasts just weeks compared to many months for aging, so a wine that is barrel-fermented but not barrel-aged will have less oak impact.
Stainless steel, unlike oak, is known for what it doesn’t contribute to wine. As a neutral, nonporous material, it adds no aromas or flavors, giving wine a crisp, fruit-focused character. Since stainless tanks don’t allow oxygen exchange, wine develops more slowly than it does in barrels.
It was these attributes that inspired Marimar Torres, proprietor at Marimar Estate Vineyards and Winery in California’s Russian River Valley, to create an all-stainless version of the winery’s oaked Chardonnay, starting in 2005.
“I wanted to make a wine that would really highlight the fruit without the influence of the barrel,” says Torres. She named the wine Acero, the Spanish word for steel. “While the barrel-fermented and aged Chardonnay has more richness and complexity, Acero emphasizes brightness and purity of fruit.”
For winemakers seeking the best of both worlds, concrete vessels combine the attributes of oak barrels and stainless-steel tanks.
“Unlike stainless, concrete is porous and allows for some oxygenation while not imparting any flavor, like oak does,” says Leslie Renaud, principal winemaker at Martin Ray Winery in the Russian River Valley, who makes Chardonnay in both concrete tanks and French oak barrels. “The oxygen exposure also allows for faster maturation than stainless.”
While concrete wine vats have been around for hundreds of years, egg-shaped versions are a modern invention. Renaud favors them because their oval configuration naturally circulates the wine and keeps the spent yeast cells, or lees, in suspension. “This gives a perception of more mid-palate weight in the wine, so it’s less austere than it would be with a stainless-steel fermentation,” Renaud explains. “Concrete provides a more complex mouthfeel.”
Shaped by clay
Amphorae, clay vessels whose origins date back thousands of years, share some characteristics with concrete tanks. Amphorae have a somewhat ovoid shape, pointed or tapered at the bottom, which allows the lees to circulate during fermentation.
However, there are differences between concrete eggs and amphorae, says Andrew Beckham, winemaker and proprietor at Beckham Estate Vineyard in Oregon’s Willamette Valley. Beckham, who is also a ceramics teacher and artist, has been making his own amphorae since 2013, and now uses them for nearly all of his production.
“We find that when we’re fermenting, and even when we’re aging the wines, a lees bed forms from the top of the container to the shoulder of the vessel,” Beckham says. “This is very unlike an egg, where the lees are down in the bottom of the wide portion of the vessel.”
This results in greater surface exposure with the lees, he adds, which builds a more supple, soft texture in the mouth. “It’s maybe like putting your tongue on a wet river stone or brick,” notes Beckham. “No aroma or flavor is imparted, but there’s a slight minerality and a dustiness on the palate. A chalkiness that’s coming from the clay.”
He also points out that, with amphorae, the fermentation process happens at a lower temperature and takes longer. “Because they haven’t gotten as hot,” says Beckham, “wines in amphorae have more tension and energy, and they’re brighter.”
5 wines to try:
These wines show the impacts of different vessels in the glass:
With aromas of jasmine, green apple, and spice, this bright and beautiful wine was fermented and aged entirely in stainless steel tanks. The purity of fruit from the Don Miguel estate vineyard shines through, with lemon and mineral notes chiming in. The wine’s creamy texture comes courtesy of 100% malolactic fermentation.
Made with fruit from the same vineyard as Acero, except the Chardonnay was fermented in 39% new French oak barrels, then aged in the barrel for nine months. The jasmine aroma is less pronounced, joined by soft vanilla and melon. Tangy and rich in the mouth, La Masia tastes like a liquid lemon meringue pie.
Fermented in egg-shaped concrete tanks, then left to rest in concrete for 10 months, this Chardonnay smells like fresh ripe peaches, with light floral accents. It has zingy acidity, with bright lemon zest and peach flavors. The texture is remarkably different from the Acero, much more mouth-filling, thanks to the natural lees suspension that occurs in the egg.
Fermented in open-top stainless-steel tanks. Then aged 15 months in neutral French oak barrels, so the oak impact on flavor and aromas is minimal. The wine has a slightly woody aroma with spicy accents, and the palate bursts with bright red cherries. Elegant with a lovely lightness, the wine has well-integrated tannins and lively acidity.
Made from the same fruit as the estate Pinot Noir, but fermented and aged in amphora. Light garnet in color compared to the estate wine’s bright ruby, with pretty floral and red fruit aromas. Fruit flavor leans more toward red raspberry than cherry, with a bit more intensity and complexity. The wine finishes with a slight dustiness.