A concrete egg fermentation tank is ideal for aging white wine, and it's especially well-suited for Chardonnay. The concrete material is porous, which allows the wine to breathe just as stainless steel and barrels do. This allows for micro-oxygenation to occur, which imparts a neutral flavor. A concrete egg's temperature can be controlled, which is beneficial for winemaking.
While they're most commonly associated with white wine, these vessels are also well suited to red wines. The narrow, oval shape of a concrete egg helps create a "vortex" in the wine, ensuring thorough fermentation. They also retain heat evenly and don't experience wide temperature swings.
While the concrete egg is more expensive than stainless steel tanks, they are comparable in price. A standard-sized 1600-liter concrete tank weighs around 2000 kilograms, or 2.2 tons. Even smaller tanks need cranes to be placed in a winery. Additionally, the costs of freight are high, especially if you live far away from the maker.
Winemakers typically stir the wine once a week or twice a month in barrels and stainless steel fermenters, but stirring is only necessary once or twice a month in egg fermenters. This process helps wine breathe more easily, so winemakers may want to consider investing in a concrete egg fermentation tank.
The main advantage of a concrete egg is its unlined structure, which allows tiny amounts of oxygen to enter the wine. This oxygen allows the wine to soften tannins and develop more complex flavors. This effect is similar to that of barrel ageing, although without the oaky taste. In addition, the wine is not cloudy.
The egg shape also provides a continuous surface for the wine to ferment. The thick walls also provide good insulation and prevent temperature fluctuations. Ultimately, the concrete egg fermentation tank allows the wine to maintain its temperature at a stable level. The egg shape also means the wine will be more stable, preventing the need for artificial refrigeration.
While French oak has long reigned as the primary wine-aging vessel, producers are increasingly turning to concrete tanks for their fermenting and aging processes. These tanks are egg-shaped and often used for fermentation and maceration. They can also be used for aging, but these tanks are less prone to imparting flavor.
