The cone, the sphere, the ellipsoid, the tulip, the truncated pyramid – wine vats come in a bewildering array of shapes these days, but none has made as much of an impact on the 21st-century wine world as the egg. The advantages of the egg-shaped vessel are several. As carbon dioxide rises through the must during fermentation, the ovoid shape creates a convection current – like a natural pump-over – which facilitates homogeneity of the must and uniform fermentations.
If the wine remains in the egg for maturation, that current continues. Werner Michlits of Meinklang in Austria explains that as heavier molecules in the wine polymerise, they sink to the bottom of the vessel and push lighter ones upwards. This creates a continuous battonage, increasing lees contact and enhancing the wine’s texture. Benefiting from the flavour neutrality and micro-oxygenating properties of the materials they are made of (concrete, clay, high-vitrification ceramics), eggs also promote fruit purity and aromatics.
Maybe it's time to try something new and fun!