Monolithos Wine Dimensions: May 2017
Wine and oak share a long connection in fact the mention of the word winery brings in mind the picture of a cellar with stags of oak barrels. The use of oak in wine is and has always been very popular. Many people associate quality wine with a wine that is aged in an oak barrel. In fact, oak leaves a lasting mark on almost all the bottles of classy wines.
While placing wine in barrels may have originated as a storage method, manufactures and winemakers have been using oak barrels for the two most vital processes of wine namely fermentation and aging for over a century. However, not all of us know how that oak is actually being utilized at the winery in order to add a palate appeal and flavour to the wine. Here’s an overview of the basics of how winemakers use oak barrels to affect wine, which you can use to broaden your understanding of the wine world altogether.
The first encounter of wine and oak starts in the process of barrel fermentation when the freshly de-stemmed grapes (a mechanical process to remove the stems from the crushed grapes) and their juices are pumped directly into oak barrels.
The barrels are then laid on a rack that allows them to be rolled back and forth daily to ensure the cap (mass of solid matter grape skins, seeds, stems, pulp which rise to the surface during fermentation) stays moist and the oak is evenly introduced to the fermenting must and juice. Typically, two full barrels of must and juice will amount to one barrel of wine.
The process of fermenting the juice in oak barrels helps to impart an added silkiness to the tannins and a rounder, more lush mouth feel. This extremely labour-intensive method of fermentation is typically reserved for only the most exclusive of wines. Barrel fermentation has become fashionable among winemakers because it is widely acknowledged that the same wine fermented in a wooden fermenter is certainly much more luscious than the one fermented in stainless steel. Even though barrel fermentation is more expensive (due to the added cost of the wine barrel in making the wine) and less controllable than fermentation in larger, stainless steel tanks. It is believed to imbue certain wines with complexity, rich creamy flavours, delicate oak characteristics, and better aging capabilities, and texture.
This fashion for oak fermenters follows the increasing habit of conducting wine's second, fermentation, so-called malolactic fermentation, in small oak barrels rather than in large fermentation stainless steel tanks. Generally fermentation on the skins in small barrels delivers consistently good results.
Maturing or even storing for a specific time wine in oak barrels exhibits one of the biggest influences on the flavour of wine. Oak is considered to be the most ideal wood for this wine aging process as it not only has excellent watertight qualities but it gives the right sort of flavours, aromas and textures to enhance the wine. Aging in oak typically imparts desirable vanilla, butter and spice flavours to wine.
The size of the barrel plays a large role in determining the effects of oak on the wine by dictating the ratio of surface area to volume of wine with smaller containers having a larger impact. In general, oak when used in the winemaking process tends to have four distinct effects on the end product.
Firstly, once fermentation is completed, most wine is left in barrels to age for six to eighteen months, depending on the type of wine. During this time, the wine undergoes various chemical changes that make it taste better. But most of these chemical changes can’t happen without exposure to air. Oak barrels are porous, allowing very small amounts of oxygen to move freely throughout the barrel and thus affect the taste and aroma of the wine itself. The biggest benefit in addition to all the flavours and tannins oak can impart is the micro-oxygenation that a barrel has to offer. Wines that are aged in barrels for long periods of time actually rely on this tiny amount of oxygen to mature, even though excessive amounts of oxygen would cause the wine to change in a negative manner — finding balance is the key to a well-aged wine. As wine ages in a barrel, it absorbs some of the wood’s chemical compounds, and winemakers have found that the flavour of oak “tastes” better in wine than other hardwoods.
Secondly, tannins can certainly come from the grapes themselves, especially in situations where the skins and stems are left in contact with the wine during maceration. For grapes that lack excessive tannins, however, oak-aging can lead to a similarly tannic wine once the process has been completed. This is because tannins exist in the wood itself, which are leached out in sufficient quantities so long as the barrels are less than five years in age. The flavours that oak barrels can impart depend upon the intensity of toasting treatment that the barrel went through. Both the intensity of and the duration over the flame contribute to the overall sensory experience and can range from green and vegetal to heavy vanilla and spice profiles. A barrel can be lightly toasted, heavily toasted and many levels in-between. Sometimes the barrels are also toasted on the top and bottom. All of these aspects give the wine particular aromatics which affects the scents a wine taster experiences. In a way, barrels are responsible for “seasoning” the wine they store.
Thirdly, the “phenol” compounds responsible for the flavour and aroma of all wines interact with oak barrels and new compounds are created, thus modifying the wine in ways that can be very difficult to predict until the final product is tasted.
Finally, during wine storage in barrels evaporation of the water and alcohol takes place. It is water that mostly evaporates out of the barrel. This means that the longer the wine stays in the barrel the more concentrated the flavour and alcohol will become. So even if a barrel no longer has much oak flavouring to impart on the wine the flavours of the wine it will become more concentrated over time. A wine barrel will lose approximately 20ltrs of wine per year to evaporation. Regardless of the oak utilized, it will impart many characteristics influencing the mouth-feel, texture and body of a wine.
Furthermore oak has a way of stabilizing the colour of red wine. This enables the wine to retain its colour even with age once it is in the bottle. The influence of colour oak has is more noticeable in white wines. A white wine which has been "oaked" takes on a more golden hue. This is not only from the oak itself but from the controlled oxidation of the wine as well. The resulting wine will usually taste richer, with creamy vanilla undertones and sometimes a little woody. With the exception of Chardonnay, oak is rarely used when making white wines. Oak has a way of stabilizing the colour of red wine. Maturing wines in barrels also helps to stabilise the tannins that are so important during a wine's aging process, and clarifies the wine much more naturally and effectively than simply chilling, or adding chemicals to, a tank full of wine.
Briefly, the following changes are the result of chemical transformations taking place during barrel ageing:
· Increase in the colouring intensity.
· Evolution of the hue: the colour of red wine takes on ruby nuances.
· Stabilization of colour during aging; the tannin/anthocyanin complexes formed during these reactions are more stable than the anthocyanin molecules which alone are responsible for the colour in young wine.
· Precipitation of the large tannin molecules (with various other elements), which in the long term guarantees the clarity of the wine.
· A decrease in astringency and hardness and the acquisition of ‘softness’, and smoothness, characteristic of red wine.
Oak barrels tend to shield maturing wine from variations in temperature and the result is usually a rounder, smoother, fuller wine that is more flattering to taste. However a thin and poor wine is not helped by being stored in barrels. Oak isn’t for every wine. Oak barrels require wines that have quality grapes and structure. Sometimes people believe that oak can destroy the flavour of the wine, but that is only possible if the grapes or structure are weak or a winemaker uses the wrong kind of oak. A perfect use of oak doesn’t overpower the grape’s character. It should provide balance. How much oak or new oak to use is not an exact science. It depends on the intended style and concentration of the wine. Oak flavours in wine must never be overwhelming and organoleptically noticeable.
Barrel aging has a lot of influence on wine particularly if it is new and freshly toasted. Its influence is diminishing with time and becomes minimal because it is old. Barrel aging requires judicious control and strict supervision to obtain best results. It should carry only a supporting role and never dominate. Winemaking is a labour-intensive art. Vintners spend years learning how to combine specific grapes and oak to produce their classic vintages. In fact, when successful each successive bottling has its own unique taste and texture and the older the wine, the better it taste. There is no one scientific philosophy that needs to be followed for the production of a balanced wine. And that is where the art comes into wine. Taste is the most important determining factor of how long a wine should spend inside of a barrel. Aging wine in an oak barrel is all about imparting the correct level of flavour and structure to any given wine.
Barrels will cost the most and require upkeep between wines to make sure they don’t become a haven for spoilage microorganisms. A stainless steel tank may be cheaper and easier to clean and maintain but red wine well stored in oak has a much deeper, more stable colour than one kept in tank. Apart from their attractive price, stainless steel vats have two indisputable advantages for the vinification of red wine. On the one hand they are easy to maintain, and on the other they permit, in principle, simple and strict fermentation temperature control. Stainless steel vats offer both comfort and safety in their use. Besides, there is no doubt that stainless steel vats are definitely preferable to badly maintained and badly cleaned wooden ones.
One of the things that emerged over the centuries about wine is its relation to tradition. Over the last 100 years, wine making has been revolutionised as an art and science. While technology such as refrigeration and stainless steel tanks have made inroads into modern wineries, the basic winemaking approach is pretty much the same now as it used to be a century ago. One of the links with tradition that even the most modern of wineries maintain is the use of oak barrels. It offers an interaction with wine that skilled winemakers have used to their advantage. Barrels are re-used for several years, and the amount of new or old oak used in a wine is important. What this means is that even modern wineries will usually have some barrels – perhaps their only link with the past. For a winemaker, barrels are a critical tool, and choosing the right ones and using them in the right ways is one of the main ways that winemakers can alter the flavour of wine.
Learning about oak and how it changes wine can deepen the experience, and it’s more straightforward than many people think. Of course when tasting wine one should always have in mind that there are plenty of other variables, including varietal breakdown, vineyard sourcing, the ripeness of grapes at harvest and fermentation techniques that can influence the end result just as much. Oak or no oak ultimately reading and tasting, you will quickly develop a roster of go-to wines that suit your drinking style and this is the only fool proof way to develop your palate.