December 01, 2023 - 4 comments
If the recent release of Beaujolais Nouveau left you pondering the term as it was thrown around the wine bar, don’t worry — we've got you covered.
Carbonic maceration is a winemaking technique where whole, intact, grapes are placed in an anaerobic sealed tank, saturated with carbon dioxide to trigger intracellular fermentation (also known as enzymatic fermentation).
Intracellular fermentation, is a process that occurs within the individual grape berries themselves. Typically, during winemaking, grapes are crushed to release their juices, and fermentation begins thanks to the combined action of yeast, natural grape sugar and oxygen. However, with carbonic maceration, the CO2 present in the sealed vessel pushes out the oxygen and permeates the grape skin; the enzymes and natural sugars within the grapes interact to kickstart fermentation, turning the sugars into alcohol. This happens without the need for the traditional crushing of the fruit.
Often wide and low vats are used so the weight of the grapes at the top doesn't crush the whole grapes at the bottom. This also means careful harvesting to ensure none of the grapes have already been squashed.
So how does the CO2 get into the fermentation vessel? Well, to kickstart the fermentation, CO2 is manually added, or grape juice that is already fermenting, called ‘pied de cuve,’ is added. As CO2 is released naturally during fermentation, this is enough to fill the vessel with CO2 and start intracellular fermentation. As more of the grapes begin to ferment, more CO2 is produced, and the cycle continues.
Many winemakers practice semi-carbonic maceration. This usually happens in a more classic vat (high and narrow). This way the weight of those on top crushes the grapes at the bottom of the tank. They then begin to ferment in the juice, while those on top (intact) will begin intracellular fermentation.
Carbonic Maceration is synonymous with the production of Beaujolais Nouveau, carbonic maceration elevates vibrant, berry-like flavors while minimizing tannin extraction, resulting in a soft and approachable wine. The technique now extends beyond Beaujolais, with global winemakers increasingly embracing it to craft easy drinking wines with pronounced fruitiness and a lively character.
The discovery and development of carbonic maceration isn't attributed to a single individual but evolved over time through experimentation and contributions from mid-20th-century winemakers. One key figure associated with popularizing and refining this technique is Jules Chauvet, a Beaujolais winemaker and chemist.
So next time someone mentions Carbonic Maceration over a glass of chilled red, throw in some facts about Intracellular fermentation and let your inner wine geek run free!
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