Concrete Egg / Vessel

A concrete egg is an ovoid fermentation and aging vessel constructed from food-grade, unlined porous concrete. The format was created in 2001 when Michel Chapoutier, a pioneering biodynamic producer in the Northern Rhône, collaborated with Marc Nomblot of the Burgundy-based Nomblot company to produce the first egg-shaped concrete vat. Nomblot, which had been manufacturing concrete wine vessels since 1922, scaled up production commercially after completing Chapoutier's original 600-liter prototype. In the United States, Sonoma Cast Stone of Petaluma, California, entered the market after founder Steve Rosenblatt was introduced to the concept around 2008 by winemaker neighbor Don Van Staaveren, selling its first egg to Thomas George Estates in 2010 and launching full production in 2011.

• Nomblot has manufactured concrete wine tanks in Burgundy since 1922; the company is now owned by the Béton Concept group and operates from Torcy, France
• Nomblot's egg is composed solely of Loire sand, gravel, non-chlorinated spring water, and cement, with no chemical additives or iron, making the resulting concrete genuinely neutral
• The egg's ovoid shape traces its inspiration to ancient Roman dolia and amphorae; Nomblot's ovoid tank form is calculated according to the proportions of the Golden Ratio

The concrete egg's two key functional properties are its porosity and its geometry. Because concrete is a semi-porous material, oxygen permeates through the vessel walls in small quantities, providing the gentle micro-oxidation that softens tannins and develops complexity, similar in principle to what occurs in an oak barrel but without any extractable flavor compounds. The egg's curved shape, with a wider lower chamber tapering toward the top, creates a thermodynamic convection current during fermentation: active yeast rises, cooler wine sinks, and the continuous vortex keeps lees in suspension throughout. This natural movement performs the equivalent of frequent bâtonnage, building body and texture without pumps or stirring paddles. Concrete's high thermal mass also insulates the fermenting wine, producing more stable temperatures without artificial refrigeration.

• Concrete is porous but flavor-neutral: it allows micro-oxidation comparable to oak but imparts no vanillin, oak lactones, or toasted grain compounds to the wine
• The convection vortex generated by the egg's shape suspends lees continuously, providing ongoing lees contact that builds mouthfeel and mid-palate weight
• New unlined concrete eggs must be prepared before first use with a tartaric acid wash to neutralize any residual alkalinity from Portland cement in the mix

Wines fermented or aged in concrete eggs display a recognizable set of sensory characteristics that set them apart from oak-aged or stainless-steel equivalents. Compared with stainless steel, concrete-aged wines show greater body, textural richness, and aromatic development, derived from both micro-oxidation and continuous lees contact. Compared with oak-aged wines, they show purer fruit expression and higher aromatic precision, with none of the vanilla, spice, toast, or caramel notes that barrel staves contribute. Winemakers conducting comparative tastings consistently report that concrete produces wines with more weight and complexity than stainless steel, while preserving varietal purity more faithfully than oak.

• Richer mid-palate weight and creamier texture than stainless steel, attributable to lees-derived polysaccharides and proteins in constant circulation
• Zero oak-derived flavor markers: no vanilla, coconut, toasted grain, or caramel notes that would indicate barrel aging
• Enhanced minerality and terroir expression, unmasked by wood compounds; some producers incorporate local soils or aggregates into their concrete mix to add a literal dimension of place

Adoption of concrete eggs spans both Old and New World producers across varied wine styles. In Bordeaux, Château Pontet-Canet, the only certified biodynamic classified growth in the Médoc, introduced Nomblot eggs for its 2010 vintage alongside its existing wooden and concrete conical vats. In California, Donkey and Goat, founded in Berkeley by Jared and Tracey Brandt in 2004, has established itself as a standard-bearer for minimal-intervention winemaking and uses concrete eggs as a central aging vessel. Napa Valley's Galerie Winery uses concrete eggs specifically for fermenting and aging Sauvignon Blanc and Riesling, citing superior influence on texture and complexity. In Argentina, Zuccardi Valle de Uco has committed extensively to concrete, using custom eggs made from rocks and clay sourced from nearby rivers, adding a literal local dimension to the vessel.

• Château Pontet-Canet (Pauillac): a Fifth Growth and certified biodynamic estate that incorporated Nomblot eggs starting with the 2010 vintage for Cabernet Sauvignon-dominant blends
• Donkey and Goat (Berkeley, California): founded 2004 by Jared and Tracey Brandt, using concrete eggs alongside neutral oak as a core vessel for minimal-intervention Rhône and Burgundy varieties
• Zuccardi Valle de Uco (Mendoza, Argentina): uses custom concrete eggs made from local river rocks and clay, with thousands of liters of capacity dedicated to Malbec fermentation and aging

Concrete eggs occupy a distinct position in the spectrum of winemaking vessels, combining attributes from stainless steel and oak while replicating neither. Stainless steel is fully inert and non-porous, preserving primary fruit aromas and natural acidity but providing no micro-oxidation or lees integration. Oak barrels offer micro-oxidation alongside significant flavor extraction (vanillin, oak lactones, toasted tannins), which can overwhelm delicate varietal character. Concrete eggs sit between these poles: porous enough for gradual oxygen exchange without flavor contribution, and shaped to naturally integrate lees. Amphora and terracotta vessels offer a related alternative, with higher and more variable micro-oxidation rates depending on clay composition and wall thickness. Egg-shaped vessels are also produced in permeable polyethylene (Flextank, launched in 2012) and microporous ceramic, offering lighter and less expensive alternatives to concrete.

• Stainless steel: fully inert, zero micro-oxidation; ideal for preserving primary fruit and acidity but insufficient for sur lie complexity or tannin development
• Oak barrels (225 liters): micro-oxidation plus significant flavor extraction; effective for structured red varieties but can overwhelm aromatic whites and delicate reds
• Amphora and terracotta (qvevri, tinaja): variable micro-oxidation and mineral character depending on clay type and porosity; higher rustic variability than concrete

Concrete eggs are most strongly associated with white wines that benefit from lees complexity without oak influence: Chenin Blanc, Chardonnay, Sauvignon Blanc, and skin-contact whites are particularly well served by the vessel's neutral, oxygen-permeable environment. For red wines, the format is gaining traction for varieties where fruit purity is prioritized over oak structure, including Pinot Noir, Cabernet Franc, Gamay, and Malbec. Surveys of North American concrete egg producers indicate that Cabernet Sauvignon and Pinot Noir are among the most common red varieties being fermented in concrete eggs in the United States. The vessel is used globally, with documented adoption in France, the United States, Argentina, Australia, Chile, and South Africa.

• Aromatic whites and skin-contact wines: concrete's flavor neutrality preserves varietal and terroir character unmasked by wood, while micro-oxidation supports tannin development in orange wines
• Pinot Noir and Malbec: leading red varieties in concrete egg programs in California and Argentina respectively, prized for fruit purity and textural richness without oak influence
• Muscadet and Chenin Blanc: Loire Valley white wines benefit from prolonged sur lie aging in concrete, gaining depth and volume while preserving mineral freshness