The Oak and the Barrel
It is considered that the Celts were the first around 1000 BC who used wooden barrels of carved wood (gallier & bojer) for transport. They had a high level of craftsmanship in metal- and woodworking and a sophisticated culture, except writing. The Greeks had great respect for this highly developed people and gave them their name. The word "Celts" means brave and noble.
Researchers assume that the Celts and Romans learned the viticulture of the settled Greeks by around 600 BC in the south of France. In turn, they learned later from the Celts the barrel construction. The Celts managed to build the barrels in shape of staves in order to transport and store liquid around 300 BC. Some of Celtic tribes imported wine from the Greeks in large quantities in the early 500 BC. Other Celtic tribes abstained from wine. Their druids were skeptical of that drink. Later, the Celts traded their slaves for an amphora of Italian wine. Greek geographer Strabo (63 BC - AD 20) wrote about celtic bojern and lingonen south of the Po river, which were able to win large quantities of wine and store it in wooden barrels. Historians still disagree as to whether the Celts really learned viticulture from the Greeks, or had mastered it before.
Roman scholar and officer Gaius Plinius Secundus Maior wrote in his 37-volume, encyclopedic work "Naturalis Historia" that the Gauls dominated the refinement of the vine by "grafting". He also wrote in detail about wine barrels of the Celts, which he described as a vessel composed of staves, closed at the top and bottom, and held together by hoops. From the Celtic wine culture testify numerous archeological artifacts, such as in our Ruwer Valley, in Austria and especially in France.
(source: wikipedia, Lexikon des Mittelalters, Wein Enzyklopädie)
The wood of acacia, oak, chestnut, cherry, redwood and poplar is used for barrel construction. Hard oak wood is denser than most wood species. Because it has no resin channels, no resin is emited to the wine. Oak is flexible and influences positively the aromas with various sweet and spicy tannins. Oak wood is very resistant, that´s why it has been worshiped in mythologies. It is a science in itself to find the right balance between the oak wood and the proper wine. Micro-oxidation and strong flavors survive only excellent wines. Therefore, a stored and matured red wine from wooden barrel is considered a high quality wine today.
The way in which the wood affects the wine depends on the type of oak and its growth, on the cut and processing (also storage) of the wood, on the age and volume of the barrel, duration and temperature of the toasting (for wine 10-15 Minutes at 200-250 degrees C), and how the barrel was previously cleaned (simple barrels are cleaned with sulfur and caustic soda). Toasting (roasting) and Charring (charring the wood surface of about 2-4mm) break down the tannins and various organic compounds. The barrel is cleaned, various flavors are limited or promoted. Charring works like an activated charcoal filter, which binds undesirable substances such as sulfur compounds.
Today, smaller barrels are chosen to make the wine faster drinkable (more wood surface-more oxygen). It could also be said this way: the bigger the vessel the smaller the influence of the wood and the smaller the vessel the more intense are the aromas in wine. Young wood, which is used today mostly only 3 years, emits fresh flavors such as sweet vanilla to the wine. Later, these barrels refine the aroma by storing Cognac, Armagnac, Sherry, Madeira and Whiskey. By "toasting" (roasting the wood) in a cooperage results also roasted aromas, such as roasted almonds / marzipan, honey, hazelnut, coffee, mocha, caramel, smoke, pepper and chocolate. The complexity in smell and taste has friends and opponents (histamine insensitivity or complain that the taste of wine is lost). Wine in bottles lose its barrique flavour over time, but also other complex taste nuances are created.
Among the different types of oak, three main groups are used as the basic wood for barrel construction:
1. Sessile oak (quercus sessilis) also known as holm oak, winter oak and heather oak. It is tree of the year 2014.
2. English oak (quercus robur) also known as summer oak or French oak. It is tree of the year 1989.
3. American white oak (quercus alba).
European origin are the sessile and English oaks, which, however, have very different requirements regarding their location.
English oak is more winter hardy and resistant than the sessile oak that allows it a much wider range. Rhineland-Palatinate has the largest oak area in Germany with over 26,000 ha. Compared to the US with 45,000,000 ha of oak forest, our area is obvious smaller.
Sessile oak is the noblest and most expensive among oak woods. It is characterized by its tightness and unique purenaceous aromas.
The staves of European oaks are split by hand in the fiber direction, because sawing would make the structure porous and the barrels later leaky. Despite its high price, it is used more often in France, Italy and Austria. Many stocks of the sessile oak can be found in the Palatinate Forest, Spessart, Middle Franconia and Rhine- Moselle area.
Here at the Moselle and partly at the Rhine the traditional Fuder (piece barrel) is known very well. Such barrel contains 1,200 litres. Right from the start: besides the origin of the wood, drying and processing are also crucial. The oak should grow at least 80 years, even better 100-150 years. Freshly cut oak contains 6% tannin in the wood. It smells sour and has 3.9 pH. Both European oaks are among the ring-porous wood species. To get small pores, they must be cut in winter. Such porous structure makes necessary, after the trunks have been cut, to split them into 4 parts. Splitting them lengthwise would mean that the barrel of European oak would later become leaky. American oaks are less porous that means that the staves can be sawed. This reduces significantly the manufacturing costs. Costly splitting is done by hand or by machine splitting wedges along the natural fibers of the wood.
Before wood processing it has to dry. Ideally in the open air (at 14-16% humidity), drying of the wood takes between 18-36 months. The rainwater shall wash out the tannins and boost the formation of enzymes and microorganisms. Using drying systems, this process can be shortened, but then it is considered as quality-reducing. The staves are shaped by heat in the steam bending process and held together with tires. To preserve the classic barrique aromas, the wooden barrel must be "toasted" over an open fire. The inner barrel walls are fired with an open flame.
Nunc est bibendum! (Let's drink a toast, it's time to have a drink!)
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