Most of us are familiar with archaeologically restored clay vessels and amphorae from Greek and Roman sites: these clay vessels preceded wooden vessels for storing wine and other liquids. But according to some sources, the existence of open wooden vessels in Egypt has been mentioned for 2690 years. B.C. Fully enclosed wooden barrels for wine were first mentioned during the Iron Age (900-800 BC) and were already widely used in the first century BC for the storage of wine, beer, milk, olive oil, and water.
The Origin of the Wooden Barrels for Wine
As trade and transportation evolved, transporters discovered that wooden barrels for wine were much more practical than brittle clay vessels, and barrels began to develop in proportion to the growth of trade. Already in the second century AD, wooden barrels and tubs almost completely replaced the former clay vessels.
The most important advantages of a wooden barrel were, first, their strength: they were made of wood encircled with hoops (which were initially also wooden and later metal) that joined the ends of the barrel in the form of a double arch. Second, the barrels had a round shape, which greatly facilitated manipulation (they could roll). And third, certain products – such as wine – have been found to benefit from storage in wood. This third advantage has become the basis of today’s modern barrel. In fact, this is the only reason for the survival of the wooden barrel in the world of stainless steel and neutral synthetic materials. That advantage goes beyond all other advantages that the wooden barrel has ever had.
We all know that the vast majority of premium wines mature in oak barrels. But why? What are the benefits? Are there any disadvantages? Are there different types of oak? Why are they different? What do these differences represent? What’s this all about?
Why Do We Still Use Wooden Barrels for Wine?
If the practice of using wooden barrels for wine storage had not been common over many years when it was most practical for this purpose, it is highly unlikely that today’s winemakers would come up with the idea of adding an oak flavor dimension to their wines. We can, therefore, say that it is a happy historical coincidence that oak and wine have come together to create richer and more complex flavors and textures than would ever be possible in neutral containers.
How, in fact, is a barrel of the oak (and oak is, without exception, the only type of wood used to store premium wines) affecting wine, i.e., how does it enhance and become better?
Wine Aging Before Bottling
After the fermentation is complete, the wine is racked several times to free it from excess sludge. The young wine is coarse, raw, and green and needs a certain amount of time to calm down. This aging of the wine (“calming”) can be done in neutral containers such as stainless steel, concrete tanks, etc., or it can be done in small, relatively new wooden barrels for wine that are not neutral but have a positive effect on the evolution of young wine.
If you wish to know more about the wine aging technologies, then this is a must-read book for you.
Impact of the Oak Barrel – Basic
As the wine ages in the oak barrel, subtle aromas are incorporated into it. Different types of oak (the most widely used are French and American oak) from different regions (Limousin, Nevers, Troncais, etc.) give different flavors to the wine (the most common vanilla flavor).
When the wine is resting in a barrel, it undergoes various chemical changes, which at the end of fermentation result in greater complexity and the softening of coarse tannins and aromas. The impact of different types of wood on different wines is a ubiquitous topic of discussion and experimentation by winemakers around the world. The barrel, in principle, does the following: enables slow oxygenation of the wine and incorporates the character of the individual wood into the wine. (This effect is reduced by frequent use of the same barrel. Usually, 50% of the extract of the barrel into wine is excreted in the first use, 25% in the second, and subsequently less and less.)
We Look at the Benefits of Contacting Wine With Oak in Two Ways
For red wines, controlled oxidation takes place during maturation in a wooden barrel. This peculiar oxidation results in a decrease in pungency and an improvement in the color and stability of the wine. It also causes the fruit to evolve into more complex aromas. Through the process of filling the barrel to the top and transferring the wine from barrel to barrel for the purpose of refining the wine, just enough oxygen is supplied to the wine to allow these beneficial effects of wood on the barrel to take place over many months.
Oak contains several types of chemical compounds, each of which contributes to the wine with its taste and textural note for both white and red wines. The best known are vanilla flavors, sweet and toasty aromas, notes of tea and tobacco, and above all, the structural complexity of tannins mixed with grape tannins (in red wines). The compounds that create these delectable experiences in a mature wine are: Volatile phenols containing vanillin. Carbohydrate breakdown products are containing furfural, the “culprit” for the sweet toast aroma. Oak lactones that give the aroma of the wood. Terpenes that provide notes of tea and tobacco, and hydrolytic tannins that provide relative opacity, or “taste of wine in the mouth.”
The chemistry of oak can have different effects in terms of quantity and quality of taste and texture depending on the production techniques of the barrel and the wood used. American oak (Quercus alba) or French oak (Quercus robur), sawn or tiled wood, natural or artificially dried, use of hot water, steam, natural gas or firewood when bending staves are some of the most important features of the oak barrel production process. As you can imagine, barrel makers and winemakers from around the world differ significantly in their opinion about producing the best barrel! But what we can all agree on is that barrel production is an extremely complicated skill.