In December 2020, 2 new cement tanks for refining the wines were brought to Mas Martinet, specifically 2 cement egg-shaped tanks with a capacity of 2000 l each one. We didn’t know whether to laugh or cry! Harvest was expected to be low, and we didn’t have wine to fill them… but we were there, in the middle of the new room, ready to use them. 

Cement has been a material used in wineries, but with straight lines, and designed mostly for fermentations, taking advantage of the fact that it allows the heat from the process to be regulated more easily and to keep a more stable temperature, therefore enabling longer fermentations and a slower extraction of the tannins. Although we have used this kind of tank for the ageing process, it isn’t the most common situation. The cement eggs that we bought in 2020 were purchased thinking of a refinement process of the wine, using the microoxigenation produced by its porosity and, specially, looking for the moment, the circulation of the wine, which is caused by the shape of the container. 

Cement was already used in ancient times (the concrete lacus found in Roman villas built in the first centuries of our era). In the 19th century, its use was extended to wineries regarding both, fermentation and storing of wine. However, the tanks were used with some kind of coating to prevent direct contact of the material with the wine, therefore preventing the degradation of the tank too (which is vulnerable to certain components of the wine, and especially to its acidity). They were also coated to avoid the taste that they could give to the wine and, of course, to make their cleaning easier. Recently, this coating has consisted of epoxy resins. Nowadays, the cement used is suitable for food use. It has a degree of porosity which is similar to that of other materials, and it isn’t coated on the inside, only a layer of tartaric acid is applied to make it waterproof. 

The cement eggs have a thinner layer, of around 10 cm. thick, and it enables us to get a softer acidity. And, the most important thing, its egg shape. This shape produces a vortex effect which is very valued (a rotary flow, sometimes swirling, like a spiral), and it enables the movement of the finest lees, adding volume and smoothness to the wines. In other words, it creates a constant bâtonnage, but saving us oxidation and contamination problems that can be caused by opening a container.

An end to oxidative ageing that finishes and polishes the wine, leaving it ready for the next step, the bottling process.