What Is Carbonic Maceration in Winemaking and How Does It Work?

If you’ve ever sipped a wine that tasted like a sun-warmed banana or a fresh piece of pink bubblegum, you’ve experienced carbonic maceration. 

Carbonic maceration is a technique used during the fermentation process when grape juice becomes wine. Generally, this happens because yeast eat the sugars in the grape juice and convert them to alcohol. But, with carbonic maceration, this evolution is kicked off when winemakers fill a sealed vat with carbon dioxide to remove the oxygen. Then, whole bunches of grapes are added. 

This causes the conversion from juice to wine to happen inside the grapes themselves. 

Carbonic maceration is used to produce fresh, fruit-forward, soft wines that are instantly approachable. While traditionally used with red wines, especially Gamay, it can also be used with whites. Once you know what to look for, its flavor is instantly recognizable. 

“In general, I find the process dials up the candied fruit character on a wine,” says Bertus van Zyl, head winemaker at Calistoga-based Tank Garage Winery. “Watermelon Jolly Rancher, strawberry Starburst, and Mango Hi-Chew are all things I have tasted in our wines that undergo the carbonic maceration process. Texturally, I find the wines tend to have more width and roundness on the palate, and softer tannins.”

Conversations about carbonic maceration with experts almost always include arcane tangents about enzymes and the intracellular structure of grapes. It is, in many ways, a complex technique used to produce easy-breezy wines. 

Born in France, now a global citizen

Carbonic maceration was discovered in 1872 when French chemist Louis Pasteur found that grapes kept in carbon dioxide tasted different than those kept under normal conditions. Michel Flanzy made wine using carbonic maceration in 1934. 

During the 1970s, a trailblazing cohort of winemakers in Beaujolais known as the “Gang of Four” (Marcel Lapierre, Jean Foillard, Jean-Paul Thévenet and Guy Breton) began to use carbonic maceration to produce lighter wines.

The technique wasn’t widely popularized until Georges Duboeuf used it to produce Beaujolais Nouveau. The popularity of his wines (at their height, they sold more than one million cases per year) inspired others. 

“Many other regions use both full and semi-carbonic maceration to enhance aroma and complexity, and to soften the tannic structure of red blends and enhance aroma and earlier drinking potential,” says Eric Hemer, senior vice president and director of wine education at Southern Glazer’s Wine and Spirits of America. “Carbonic maceration lowers acidity and adds fruit aromas often described as cherry, strawberry, banana, and tutti-frutti bubblegum. There is also a noticeably lighter, softer texture on the palate.”

Though it’s widely used, carbonic maceration is not widely understood, even among experts. 

“Reading articles, drinking the wines and even knowing the science can’t quite prepare you for the magic of unsealing a tank of grapes that have gone through carbonic maceration,” says Andrew Latta, owner and winemaker at Seattle’s Latta Wines. “Removing the tank lid reveals perfectly intact whole clusters, seemingly in stasis after days or weeks in the dark, and you wonder if you’ve accomplished anything at all. The visual belies the incredible work that carbonic maceration has done down at the intracellular level, but your nose is the first confirmation when bombarded with intense aromatics of cinnamon, sandalwood, a kaleidoscope of slush-puppy syrups, and blood oranges.”

While carbonic maceration is synonymous to many with the region of Beaujolais and the Gamay Noir grape, Latta says that he’s used the technique on Pinot Gris, Pinot Noir, Mourvèdre and Syrah for the past eight years. 

Increasingly, winemakers see carbonic maceration as an ally for many reasons.

As van Zyl worked with a small block of Petit Manseng grapes in El Dorado County in 2019, he wanted to produce a wine that downplayed the grapes’ inherent sweetness, yet accentuated their natural acidity.

“I spent a lot of time trying to figure out how to make a non-sweet white wine that would not be overtaken [by] the grape’s high acidity,” says van Zyl. “With carbonic maceration, the enzymes will use the acid as one of their food sources along with the sugar in the grapes, so the result of letting the process happen gives you a wine with less acidity and a whole new range of flavors. I remember the wine tasting like a Mai Tai cocktail because it had so much pineapple jumping out of the glass.”

At Gran Moraine, winemaker Shane Moore has found that carbonic maceration helps tamp down the unbridled acidity of Gamay Noir grown in cooler climates like the Willamette Valley. 

“For us, carbonic maceration allows the Gamay’s fruit aromatics to pop more,” says Moore. “It extracts the flavors and aroma you want in Gamay while reducing the acidity that accompanies growing Gamay in a cool climate.”

From full-on carbonic to shades of spice and complexity

The technique is flexible. It can deliver innumerable shades of bubblegum flavors in the glass.

Matias Kúsulas, co-owner and winemaker at boutique Washington wineries Valo Wines and Massalto Wine, makes full- and semi-carbonic, whole-cluster wines with Cinsault, Mourvèdre, Syrah, Tempranillo, Viognier, Muscadelle and Pinot Gris. His approach changes from grape to grape.

“Cinsault, having big berries and fairly low tannin content, works great with full carbonic,” says Kúsulas. “The wines show better texture and aromatic complexity.”

He says that he tones down the “bubblegum and banana, while enhancing red fruit, citrus and savory,” by aging the wines in French oak barrels for at least 14 months. 

Kathleen Inman started to experiment with carbonic maceration in 2009. Four years later, she dialed up her commitment with a large-scale, 100% whole-cluster fermentation of Pinot Noir at Inman Family Wines in the Russian River Valley. 

“I think carbonic maceration provides high-tone fruit and a ruby grapefruit character,” says Inman. “Overall, it’s the spice and complexity it adds that I really like.”

She doesn’t always go 100%, as she’ll dial back as needed with Pinot Noir and Grenache. When Inman decides to use full carbonic maceration, as she did in 2013, 2015 and 2019, it’s a (huge) labor of love.

“Loading the tank is easy, but after 30-35 days in the tank, the whole clusters have to be removed through the tank’s small main door with a pitchfork,” says Inman. “About five tons of grapes have to be shoveled out. And with whole-cluster carbonic [maceration], the juice has fermented inside the individual berries, so only a small amount of juice is released from the weight of the grapes.”

At Domaine Mont Bessay in Beaujolais and Domaine du Cellier aux Moines, head of vineyards winemaking Guillaume Marko says he never goes 100%. He utilizes carbonic maceration only at the beginning of the fermentation process. While those who employ full carbonic maceration will press the grapes after a week or so and finish fermentation off the skins, Marko will continue macerating on the skins to extract additional tannins. He says the choice is a matter of style, flavor and structure.

“Using it at the beginning of fermentation gives the wine very interesting aromas: spicy and fruity,” says Marko. “We use it on our Pinot Noir and Gamay when we’ve had a vintage with good maturity. I don’t use it every year. And I only use it up to a point because I want to infuse the grapes with fresh aromas, but I also want the structure and tannins that come at the end of a long maceration on skins.”

Marko finds that 100% carbonic maceration creates a delicious, easy wine that he enjoys drinking during summer. “For us, we want to make wines that fully reflect our terroir,” he says. “And we feel we can’t do that unless we have the structure that time on the skins gives us.”

Adrien Duboeuf-Lacombe, deputy managing director of Georges Duboeuf Wines, also favors semi-carbonic maceration, especially for the more valuable and ageable Cru wines. 

“We generally start the maceration process as semi-carbonic and then transition to a more traditional maceration to allow for a longer-lasting process that imparts more structure,” says Duboeuf-Lacombe. He says it seems to create a balanced wine that appeals to serious and newer enthusiasts alike. “The taste profile is trending, especially for the younger generation, with fresh fruit aromas, lower tannins, lower alcohol.”

The building blocks of winemaking have generally remained the same for centuries, but carbonic maceration has added a different way to dial certain flavors up or down. Depending on how it’s utilized, carbonic maceration can deliver everything from Mai Tai vibes to high-toned fruit and complexity. Bring on the sunshine in the glass.