The extended maceration process used here keeps the skins and seeds in contact with the wine for far longer than the typical 7 to 10 days that a red wine would spend on skins. The skins and seeds of a grape are where the phenols are located; these are the molecules that give wines their colour and tannin structure. As you would expect, the longer the skins are in contact with the wine, the more tannin content in the resulting wine. Curiously, this doesn’t actually make the wines taste more tannic, as these molecules are polymerising (binding up to become larger) during this process, which actually makes the wine appear smoother, and more elegant.

The concrete egg promotes a very slow and steady rate of oxygenation into the wine, allowing just the right amount in for the wine to develop, but not so much that the freshness of the Grenache is lost.