What Are Concrete Eggs and Tanks? A Beginner’s Guide

Quick answer

Concrete eggs and tanks are winemaking vessels made from concrete. They can be used for fermentation, skin contact, storage or maturation.

A concrete egg is usually egg-shaped or ovoid. A concrete tank, vat or fermenter is a broader term for a concrete wine vessel and may be cylindrical, rectangular, conical, oval or another shape. The names describe equipment, not a particular grape variety, wine style or quality level.

Concrete is sometimes chosen because it can buffer changes in temperature and avoid the oak flavour that comes from a new barrel. But it is not automatically neutral, porous, self-mixing or better than stainless steel. The result depends on the vessel’s design, its internal surface, cooling equipment, cleaning regime and how the wine is made.

So, when you see “made in concrete” or “matured in concrete”, treat it as one useful production detail—not a complete tasting description.

Why use concrete in winemaking?

Concrete vessels can be used during several stages of production.

During fermentation, yeast converts grape sugar into alcohol. Concrete may hold red grapes and their skins, white or rosé juice, or other fermenting wines. A concrete vessel does not decide whether a winemaker uses skins, whole bunches, cultured yeast or naturally occurring yeast. Those are separate choices.

Concrete tanks can also be used for maceration, when grape juice remains in contact with skins and other grape solids. The vessel’s shape may affect access, movement and cap management, but it does not guarantee gentler extraction or better texture.

After fermentation, wine may be held or matured in concrete. This can offer an alternative to oak for a winemaker who wants to avoid oak-derived flavour and tannin while using a vessel with different thermal and oxygen characteristics from stainless steel.

What makes an egg different from a tank?

The main difference is shape.

Egg-shaped vessels have curved walls and no corners. Winemakers and manufacturers sometimes suggest that this encourages movement in the wine as it ferments. That idea is plausible as a question of flow, but it should not be treated as a universal advantage.

A peer-reviewed study of a concrete egg found that, in the conditions tested, a jacketed cylindrical stainless-steel tank provided superior modelled mixing and temperature control. The concrete shell behaved more like an insulator than a heat sink. This does not mean every concrete egg behaves identically. It does mean that “egg-shaped” should not be translated automatically as “better mixed” or “better temperature controlled”.

A tank with a jacket or other cooling system may offer more direct temperature management. A concrete vessel without active cooling may mainly slow temperature changes rather than control them precisely.

Is concrete porous or neutral?

It depends on the vessel.

Some concrete vessels are lined, coated or sealed to reduce direct wine contact with the concrete. Others may be designed to allow more interaction with the concrete surface. The formulation, curing, wall thickness, finish and maintenance history can all matter.

This is why broad statements such as “concrete is porous” or “concrete is completely neutral” are unsafe. They may describe one vessel but not another.

Australian Wine Research Institute material records historical calcium instability associated with unlined or inadequately coated concrete tanks. Improved lining has reduced that problem, but this is not evidence that all modern concrete vessels cause chemical instability.

For drinkers, the practical point is simple: the word “concrete” does not tell you whether the vessel was lined, how much oxygen it allowed through or how chemically interactive it was.

Concrete compared with other wine vessels

Stainless steel

Stainless steel is smooth, non-porous and generally straightforward to clean. Tanks are often fitted with cooling jackets, making active temperature control practical. Stainless steel usually contributes little material-derived flavour.

Concrete may offer more thermal buffering, but temperature control varies by design. It can also be heavier and more difficult to install or move.

Oak

Oak barrels can contribute flavour compounds, tannin and oxygen exposure, particularly when they are new. Barrel size, age, toast and previous use all affect the result.

Concrete can provide a way to ferment or mature wine without the obvious oak contribution of a new barrel. That does not make concrete flavourless or guarantee a particular texture.

Clay and amphora

Clay and amphora vessels are related but not identical terms. Amphora usually refers to a vessel shape, while clay describes a material category. Porosity and lining vary between vessels.

Concrete and clay can both be discussed as alternatives to oak, but they should not be assumed to behave in the same way. For more on the distinction, see our guide to amphora and clay vessels.

Possible advantages and limitations

Concrete may offer:

• insulation or slower temperature change;
• a long-lived, rigid vessel;
• an alternative to oak flavour;
• shapes and capacities suited to particular winery layouts or processes.

It also brings practical limitations:

• considerable weight;
• difficult installation and relocation;
• possible cracking or repair requirements;
• vessel-specific cleaning and hygiene challenges;
• potentially less precise temperature control than an actively cooled stainless-steel tank;
• different behaviour depending on lining, coating and surface condition.

These are trade-offs, not a scorecard. A winemaker chooses equipment according to the wine, the facility and the desired process.

What can you infer from a wine description?

If a wine says it was fermented in concrete, you can infer that concrete was used during fermentation. If it says the wine was matured in concrete, the vessel was used after fermentation for holding or maturation.

You cannot reliably infer that the wine:

• tastes mineral;
• is fresher, softer or higher quality;
• received no oxygen;
• was made without oak or stainless steel elsewhere in production;
• is natural, organic, biodynamic or unfiltered.

“Made in concrete” is therefore best understood as a production detail. To judge its likely effect, you would need to know which stage involved concrete, how the particular vessel was constructed and how the wine was managed.

Australian context

Concrete eggs and other concrete vessels are used by some Australian wineries, including wineries in Western Australia and other wine regions. They are one option among many, not a uniquely Australian method.

Australian wine learners will often encounter concrete alongside stainless steel, oak and clay vessels in conversations about fermentation and maturation. The most useful question is not “Is concrete better?” but “What role did this particular vessel play in making this particular wine?”

Frequently asked questions

Do concrete eggs make wine taste like concrete?

There is no universal “concrete taste”. The wine’s result depends on the vessel’s surface, construction and use. Concrete should not automatically be associated with mineral flavour.

Are concrete eggs better than stainless-steel tanks?

No vessel is automatically better. Stainless steel can offer precise active cooling and easy cleaning. Concrete may provide different insulation and maturation conditions. The best choice depends on the wine and the winemaking process.

Are concrete tanks used only for red wine?

No. Concrete can be used for red, white and rosé wines, although the exact use varies between wineries and vessels.

Does concrete mean a wine is natural?

No. Vessel material does not establish whether a wine is natural, organic, biodynamic, vegan or unfiltered.

Concrete is best understood as one of several tools in a winery. It can change the practical conditions around fermentation or maturation, but the result depends on the vessel and the winemaker’s choices—not on the word “concrete” alone.