Tradition and progress characterize the raw materials chosen for the containers suitable for the fermentation and aging of wine.
Since ancient times it has been necessary to have containers to use during the process of turning grapes into wine and for transporting the wine. The use of containers for winemaking began many centuries ago in Georgia with Kwevri, terracotta vessels that were buried. The Greeks and Romans used vessels mainly for transport, by sea or land, spreading the culture of wine in the Mediterranean. The Celts used wooden barrels, made from different types of wood, for the transport and storage of wine. Thus, the use of wooden barrels spread throughout Europe, for the transport of wine and for wine-making and ageing.
The most widely-used materials to build suitable containers for wine
Steel, concrete, wood and terracotta today are the materials used for wine-making and ageing all wines the world over. Each has different characteristics that produce various effects on how the wine evolves. Here are some interesting facts about these materials:
- Stainless steel containers: are used both for fermentation and for ageing and storage. They usually have a cavity where a fluid can circulate to regulate the temperature inside the container, electrically controlled by a control unit. Temperature control in the fermentation stage is very important, especially for white wines. Stainless steel is highly resistant and lasts over time and its use maintains the freshness of aromas in the wine, favouring its aromatic expression. The material creates a reductive environment (without the presence of oxygen) and can have different shapes and capacities.
- Cement containers: cement is making a comeback for its ability to isolate wine from external agents and because it does not yield aromas to the wine. Because of its thermal inertia, it accompanies varying temperatures as the seasons change. However, it requires more care and maintenance than steel containers.
- Containers made by firing clay: terracotta, ceramic, stoneware. The temperature at which clay is fired changes the porosity of the container, so terracotta has a micro-oxygenation similar to wood, while stoneware prevents any exchange of oxygen. No aromas are transferred to the wine and new amphoras may release nuances that are perceived as earthy.
- Wooden containers: the special feature of these containers is related to the porosity of the woods used to manufacture large-capacity barrels: 500-litre tonneau, 225-litre barriques (Bordeaux containers) or 228-litre Burgundy containers (also called a pièce). In small barrels, the ratio between the surface of the wood and the volume of the wine is greater, so evolutionary processes are faster. Besides promoting oxygen exchange, wood has an important impact on the bouquet (hints of vanilla, coconut, walnut, toasting) and on the taste of the wine, thanks to the ellagitannins that develop with those of the wine, giving it structure and reducing the sensation of astringency.
Type and toasting of various types of wood
Wood is one of the most interesting materials due to the numerous types of raw materials that can be used in the construction of barrels. The finest woods are obtained from oaks, for example:
- From the Quercus Sessilis of the forests of the Allier and Nevers department in France, finely porous woods are obtained, excellent for long aging.
- From the Quercus Robur which are abundant in the forests of Limousin (France) rich, more porous woods are obtained, used for the maturation of cognac.
- Eastern Europe also supplies high-quality woods for the manufacture of barriques.
- From the Quercus Alba americana, a wood is obtained which, having a relatively coarse grain, is widely used in Spain and Australia for the ageing of red wines with a good structure.
What does the toasting of barrels mean? Toasting is a process used for small barrels, which involves setting fire inside the container, for a certain period of time, from 5 to 20 minutes, if you want a “strong” toasting, to intensify and expand the aromatic nuances.