Many people know wine is often aged in oak barrels. But there are a number of different ways to ferment and age a wine, from clay amphorae to concrete eggs. These variations can have profoundly different effects on the finished product.
“Every single wine necessitates you choosing a direction based on prior experience with a particular vineyard,” says Aryn Morell, owner/winemaker at Alleromb and Morell-Peña, and consulting winemaker for numerous wineries.
Those decisions are based on factors such as the variety, the vineyard, the vintage and the desired style of wine.
Why use different types of fermentation and aging vessels at all?
“We’re looking at all of these things as ways to add texture but without adding flavors,” says James Mantone, co-owner/winemaker at Syncline Wine Cellars.
Here is a look at some of the different vessels winemakers use, and why.
Many winemakers ferment their wines in open-top stainless steel squares or perhaps open or closed steel tanks. But, in addition to fermentation, some also choose to age their wines in stainless steel. This is particularly true of white wines.
“I use stainless steel on my [white wines] to capture the essence of the fruit in a cleaner, brighter fashion than, say, using something that would mask some of those flavors a bit, like oak,” says Sean Boyd, owner/winemaker at Sightglass Cellars.
For his white wines, Boyd uses stainless steel tanks with temperature-controlled jackets, preferring to go “slow and low,” meaning to ferment slowly at cool temperatures.
“I like what it does to the Chardonnay and Sauvignon Blanc,” Boyd says. “It helps to retain the flavor of the vineyard and its individual personality, and stays nice and crisp.”
“Why work really hard in the vineyards to produce something distinctive and then add a bunch of purchased flavors?” —James Mantone, co-owner/winemaker, Syncline Wine Cellars
Different types of vessels also have an effect based on how quickly they heat up and cool down.
“In stainless steel, basically you have a very thermally conductive surface where your temperature increases quickly and decreases quickly, so extraction happens real fast,” says Morell. “You also tend to get slightly more punchy aromatics because it’s not a real breathable surface.”
The speed with which stainless steel heats and cools remains in stark contrast to other materials, like concrete. “We tend to find that an average stainless steel fermentation is, for us, about 15–17 days,” Morell says. “When we go into concrete tanks, we tend to see that those fermentations last more like 24–27 days.” This impacts the aromas, texture and flavor of the resulting wine.
Oak barrels do three things to wine. They allow for oxygen exposure, which assists with maturation. They also provide tannins that give the wine structure. Finally, depending on the level of toast and age of the barrel, they also impart certain flavors. How these factors are managed depends on the winemaker.
“The most important things that barrels do for a wine are provide oxygen and stabilization,” says Mantone, who works heavily with Rhône varieties, among other grapes. “I think that the least important thing that barrels do for wine is flavor.”
For his wines, Mantone is looking to limit flavor impact as much as possible. “Why work really hard in the vineyards to produce something distinctive and then add a bunch of purchased flavors?”
Some varieties, like Cabernet Sauvignon, often see a larger percentage of new oak, which has a stronger impact on the wine than used oak.
“Cabernet can integrate that new oak tannin and flavor, certainly better than Rhône varietals, but I think you still have to be conservative with it if you want to project the sense of the vineyard,” says Morgan Lee, co-owner/winemaker at Two Vintners.
While many winemakers age wines in oak barrels, an increasing number are also fermenting grapes in them, believing it increases oak integration and ultimately makes better wine.
“The integration of the wood is night and day [when fermenting in barrels],” says Lee. “If you ferment in a tank and then press it and put it into a brand-new oak barrel, [the wine] really shows the wood for a long time. When you ferment in oak, it’s almost counterintuitive, the oak is way more integrated.”
Different sizes of oak barrels
Oak barrels come in all sorts of sizes. The standard barrel size, often referred to as a barrique, is 225 liters, though smaller sizes exist. Barrels can go up to 300 liters, 500 liters and even 860 liters or more. Barrels 500 liters and larger are typically referred to as puncheons.
Why use larger barrels in the first place?
“My goal is that you are tasting the vineyard and the dirt that the wine came from,” says Lee, who uses puncheons for varieties like Syrah and Grenache. “You have less surface area to liquid ratio, so [the barrel] is having much less of an aromatic impact. You still get a bit of a spice note that you’re paying for in the wood, but it’s a supporting role rather than being at the forefront of the wine.”
Morell breaks down the possible effect of increasing barrel size. “A 300-liter barrel’s effective percentage of new oak impact is probably 80–85% versus a standard barrel,” he says. “When we go to a 500 liter, we’re really talking around 60% influence. They are all new barrels, but their effectiveness…is quite different, and what they do to your phenolic makeup is also quite different.”
Barrel shapes and stave thicknesses
Barrels also come in a variety of shapes. Cigar-shaped barrels look like normal barrels that have been stretched out horizontally. Mantone uses them to ferment his estate Viognier before moving the wine to a standard 225-liter barrel.
“There’s slower oxygen movement and more lees area, so more lees contact,” he says. “It helps round out the wine.”
Meanwhile Gilles Nicault, director of winemaking and viticulture at Long Shadows, uses 5,500-liter upright oak tanks to ferment Merlot. “For the color to be fixed, you need oxygen and you need tannin,” says Nicault. “The wood brings oxygen and tannin, so you have much better intensity of color and because of the tannin, you have a better mouthfeel. It also helps bring backbone to the wine.”
The effect of oak barrels gets further complicated by the thickness of barrel staves, which can have a profound impact. Thinner staves increase the amount of oxygen the wine is exposed to, while thicker staves lessen oxidization.
Why use thicker staves?
“When you find [wine] that you need to [develop] a hair slower and you’d like to increase its fruit texture more, that’s where the thick staves start to be remarkably beneficial, especially with lighter bodied reds like Grenache and Pinot Noir,” says Morell.
Concrete has long been used to ferment and age wine in the Old World, but has recently gained popularity in the U.S. As with barrels, concrete tanks come in various shapes and sizes, from egg-shaped vessels to cubes and cylinders.
Though concrete might seem impermeable, it does allow oxygen to seep through. “Concrete does a lot of the same things that you get out of barrel, but you don’t get the wood flavor,” says Mantone. “You get the oxygen, and you get some stabilization.”
He says that with any vessel, it can be a trade-off. “We lose a little bit of aromatics that you would get in stainless steel, but we gain a lot of texture using concrete.”
The shape of the concrete vessel also impacts the resulting wine, such as with egg-shaped vessels.
“One of the beauty of eggs as a fermentation vessel is they self-stir,” says Lee. As the juice ferments, bubbles of carbon dioxide rise along the sides of the egg. “You can see the liquid pushing up along the sides and then going down through the center like a funnel to the bottom. It keeps the lees in constant suspension.” This provides greater texture to the wine.
There’s debate within the wine community about whether concrete itself also imparts some unique mineral aspect to a wine. Lee is unequivocal in his perspective.
“People say that concrete doesn’t transfer minerality, but in my experience, that’s bullshit,” he says. “That shit tastes different.”
Lee detects a distinct mineral note on the wines. “There’s a wet stone thing that comes out of the concrete tank that you definitely don’t get when you’re tasting from wood. I don’t know the science behind it, but it changes the wine I think for the better.”
Long used in Old World wine production, earthenware vessels have come into vogue in New World regions as well. The reasons behind using clay amphora are much the same as for concrete.
Referred to as tinaja in his native Spain, Alfonso started using amphora in 2017. He says these vessels are more complicated than they appear.
“[Clay amphora are] a big pain in the ass… You have a giant clay pot. You have forklifts. My entire vintage of orange wine is in a clay pot that is less than an inch thick. It’s not for the faint of heart.” —Morgan Lee, co-owner/winemaker, Two Vintners.
“There are a lot of nuances,” Alfonso says. “Each producer has their own proprietary shape. How the wine ages depends on the shape. If you want to store wine in it, then you need to close the opening at the top. The size of the opening makes a big difference too.”
Lee is blunter in his assessment of working with amphora.
“It’s a big pain in the ass,” he says. “It is the most inefficient and scary thing to use. You have a giant clay pot. You have forklifts. My entire vintage of orange wine is in a clay pot that is less than an inch thick. It’s not for the faint of heart.”
Still, Lee is intrigued by their impact. “It’s hard for me to quantify in words. The wine is kind of softer. There’s sort of a rustic minerality that comes out, which is kind of cool.”
While the desire with amphora is to lessen the vessel’s impact on the wine, it takes time. “I think this first couple of years, we’ve got a bit of a clay flavor impact on the wines,” says Alfonso. He expects the effects to lessen over time.
Can any wine vessel really be called the best?
The differences created by vessels has a profound impact on the final wine, even when used only for fermentation.
“It is really amazing to taste wines from different fermentation containers,” says Mantone. “They don’t even taste like they come from the same vineyards.”
As with any winemaking decision, there’s always a tradeoff.
“If I have Sauvignon Blanc and throw it into stainless steel drums, I’ll have something that is a little brighter, crisper, cleaner and more polished than something in concrete,” says Morell. “But I think you’re still always kind of missing a level of texture you can get out of concrete that you can’t get from the stainless steel. Maybe the aromatics aren’t quite as piercing and as punchy, but I would give up a little bit of aromatics to gain in texture.”
It’s also important to note that winemakers are not necessarily wedded to any particular vessel, often changing them between vintages, or even within vintages.
“We probably move wine from vessel to vessel more often than people would think,” says Morell. “It’s like, ‘Well, I liked the way it was in this egg in January, but in February it’s starting to get a little tense or a little reductive. Let’s move it.’ Now we’ll move it into a large format barrel, open the wine back up or visa versa.” Hybrid barrels made of both stainless steel and oak, as well as wooden eggs may soon also make an appearance in winemakers’ arsenals.
“Having more of these things available to you allows you to be a little more creative,” says Morell. “You can be a little more of a problem solver.”
Last Updated: May 5, 2023