Written in Stone – Concrete Fermenters

When you envision a winery cellar, you probably imagine long rows of oak wood barrels stacked high, or tall, shiny stainless-steel tanks as the primary vessels a winemaker stores their craftwork in. For the most part, what you’re imagining is probably pretty accurate. Our cellar is home to many oak barrels, from a variety of coopers from around the world. We also have many stainless-steel tanks: special rectangular steel fermenters hand-crafted in Quebec by a fabricator called La Garde. Both serve specific purposes and we’ve carefully selected the best pieces available for the style of wines we produce.

What you probably don’t think of is concrete. Concrete tanks are not new, but they’re not common either. They are growing in popularity very rapidly however and are being implemented in many top-tier cellars around the world.

Their shape is commonly similar to that of an egg, and today are constructed with modern fitments and accessories winemakers have come to expect and depend upon. And while the end result allows for their use in a similar way to a traditional stainless-steel tank, certain special steps must be followed. For example, a special tartaric acid solution must be used to wash the tank before it’s used, and the tank cannot be scrubbed or washed with hot water, lest it crack.

On top of the special precautions to be taken, their physical mass makes them difficult to move in the cellar; if you’re bringing in a concrete egg tank, you’d better plan on where it is going to live from the outset, because it’s unlikely you’ll want to move it a second time! But it is just that aspect of the concrete tank that makes them a great winemaking vessel; one of the most important elements in making great wine is temperature control, with only long, slow changes in temperature. The dense, thick-walled nature of these concrete tanks enables exactly that – precise maintenance of wine temperature.

Additionally, the egg shape of these concrete tanks for fermentation allows for a natural circulation as the outer areas of the wine cool, descend to the bottom of the tank, and rise as they’re warmed by the fermentation. This natural stirring further develops mouthfeel and texture, which is usually achieved through physical manipulation of the wine.

These tanks represent a relatively narrow use case, but, in that use case, they present other truly amazing results. Concrete egg tanks are best suited for wines that aren’t destined to be aged in oak (which might mask delicate fruit notes), but at the same time will benefit from micro-oxygenation – the beneficial microscopic aeration that can soften and round out a wine.

So, whereas red wines, or whites like Chardonnay, benefit from extended aging in oak, which unlocks complex notes through contact with the wood and micro-oxygenation, fermenting and ageing a wine like Roussanne or Viognier in concrete brings about the wonderful rich, creamy texture of barrel ageing while preserving the grapes naturally vibrant fruit notes.

So, while all this might sound a bit technical, it attempts to sheds some light on why winemakers are introducing concrete egg-shaped tanks into their cellars. Ultimately, they are another tool in the winemaker’s kit to direct a wine’s style in the perfect direction. For certain wines, concrete tanks blend the benefits of both oak barrels and stainless tanks, but they do come at a cost – a typical concrete tank can be over twice as expensive on a per litre basis as a traditional stainless-steel tank or French oak barrels! However, after much research and consideration, we feel the costs are far outweighed by the benefits afforded to the wines. The founding principle of Second Chapter was to make wines that went above and beyond our previous benchmarks, and one of the ways to achieve that is investment in the equipment that unlocks a wines full potential.