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Technical Information

by Vincent Bouchard

Immersion; aspersion; air-drying; shaping with steam, boiling water or flames from burning wood chips!

All these techniques have existed for a long time in the various wood-related professions. Some of them have been taken up by certain cooperages, used and described by them as "traditional method"!

Actually, only two of these techniques are used by all of the reputed cooperages: open air-drying and shaping with flames from burning dry wood chips or solid wood. These two techniques, both acknowledged and recommended by the C.T.B., are certainly the most expensive since, on one hand they require major investments in stocks of wood, which remain idle for 2 to 3 years or more for the drying time which varies depending on the place of storage, and on the other hand for the shaping which instead of taking from 7 to 15 minutes with steam or boiling water requires 20 to 30 minutes or more if it is done with flames from burning wood.

We call the immersion and aspersion techniques and the steam or boiling water shaping techniques "accelerated production techniques". In the oenological sector, these techniques can be compared to the quick methods of clarification and ageing of wines, such as centrifuging, filtering and micro-oxygenation, techniques which are quite the contrary to the slow methods of sedimentation, racking and maturing.

Obviously, every cooper or oenologist considers that his own method is the best one and that it will not have any negative consequences on the final product insofar as the aromatic ingredients are concerned! Therefore, before dwelling any longer on the subject in question, which will be the object of a future information note, the following points should be remembered;

  • A new barrel is a very expensive container mainly used for wine or alcohol to add different aromas and tastes.

  • We can compare a barrel to a teabag, which brings a high concentration of aromas and taste to the first cup, (as for the first passage of wine in a barrel), then the aromas and tastes becoming weaker at the second cup (second passage in the barrel), until all the tastes and aromas completely disappear with the last cup (from the third passage in the barrel). In these two examples (teabag and barrel) the essential factor for the user is that the aromas and tastes, although they have become weaker, remain constant right up until the end. For the tea bag, as for the barrel, the higher the temperature of the water, the stronger and quicker, the extraction will be, but also a real tea connoisseur never uses boiling water to make tea so as to avoid causing the evaporation of the more volatile and delicate aromas. So why do certain tea drinkers and coopers commit this error?

  • As for the wood, it can be compared to a sponge during drying. Wood is a porous material which, when the tree is felled during winter, contains a percentage of humidity that ranges from 50 to 60 %. Once the tree has been cut into pieces to be transformed into staves 25 to 30 mm thick, which undergo the impact of ambient temperatures or a dry wind, the wood soon looses part of its humidity. The humidity (water) will tend to migrate from the interior to the exterior of the staves carrying with it the soluble compounds of the wood. These acid and other compounds will be deposited on surface of the wood. After these compounds have been washed by the atmospheric conditions (rain, fog, snow) or absorbed by the mycelium, bacteria, etc. which form an abundant microflora on the surface of the wood. N.B.: this microflora will be destroyed by the heating of the wood or eliminated by the planing of the pieces composing the barrel (heads and staves). At the same time, during bad weather, the humidity (water) will penetrate the wood again and dilute the ligneous compounds which rise to the surface of the wood during dry windy periods. This continuous absorption phenomenon of pure water and the successive elimination of water mixed with the compounds present in the wood, depending on the climate, microclimate, the microflora and the thickness of the pieces of wood, in Burgundy lasts for 2 to 3 years to eliminate the unwanted compounds in the wood for certain wines, when being tasted. N.B.: certain residual ligneous compounds, for certain wines and certain heating processes, may be recommended. This long natural process can be compared to a sponge impregnated with soap and pressed repeatedly with the hands under the tap until complete elimination of the soap.

Miscellaneous:

  • Microcracks: during the drying period of the wood in the open air, cold and heat cause microcracks to the surface of the wood. These microcracks allow a large surface for the evaporation of the water, a better humidity penetration inside the wood and a better support of the active microflora. The neutralizing phenomenon of the wood is therefore accelerated.

  • The microflora: a study carried out in Cognac shows that the microflora differs from one region to another depending on the local climate (Burgundy, Bordeaux, Cognac, etc.) and its own microclimate (proximity of a town, neighboring forests, plains or windy hills). This microflora is partly composed of more than 200 types of myceliums that succeed each other throughout the wood ageing process. These myceliums transform certain compounds to be found in the wood into other products, which in turn can be transformed by other myceliums or micro-organisms. N.B.: we could compare them to the actions accomplished by the various families of yeasts and the microflora during the maturing of the wine.

  • Human intervention: the pieces of wood to be aged are placed on pallets but these are not always arranged in the same way from one producer to another. Examples for positioning the pallets are: on one, two or three levels, or more or less close to one another, or in lines, in blocks separated from each other. The same goes for the staves placed on the pallets. This system of positioning the pallets or staves will have a significant influence on the circulation of the wind, rain and heat. Depending on the region, and space of storage at the cooperage, every cooper has his own system of storing in the open air which will give different results from one cooperage to another.

An experiment carried out at the Tonnellerie Billon showed a difference in the fragrances and taste of a same wine aged in barrels, made by the same cooper, the wood of which had undergone the same ageing time, the same mount of heating and came from the same forest. The sole difference between the barrels was the place where the wood had been stored (Cognac and Beaune) and the different spacing of the staves on the pallets. Other similar experiments, for the same cellar, were carried out by Tonnellerie Damy with Damy wood aged in two different parts of the village of Meursault and in South Africa. In this case too, the results obtained offered different tastes and fragrances.

Some coopers, considering they were doing the right thing and anxious to obtain quick results or a constant wood quality, have decided to use immersion or aspersion with a volume of water corresponding to several years of rain and mycelium content! Without going into the detail such as the quality of the water used, the population and the diversity of the myceliums, the quantity of circulating water, we think that, considering the results, the wood cannot be hurried.

For example: if we try to place a sponge with a compact structure and saturated with soap in a large bucket of water or under a shower of water without any pressure and after a while we remove it, squeeze it and allow it to dry, it would at first sight seem not to have any traces of soap. But if it is immersed in water again and squeezed we will see that the soap is still present inside. For wood and its compounds it is the same thing. Indeed, it is not sufficient for the wood to be immersed or sprinkled heavily with water for a short time, it is necessary for this process to be slow and gradual so that all the compounds of the wood present inside are pushed outwards and that the ageing is natural. That is why, despite the depth of the toasting, aggressive fragrances can be found in wine coming from certain barrels, which migrate from the deep part of the staves to the wine, especially after the second maturing passage and thereafter. This means that the wood has undergone the same process as the sponge: the compounds in the wood which, with a natural ageing would have been expulsed, have remained prisoners in the depth of the wood and emerge after some time.

Other coopers, they too considering they are doing the right thing, prefer to use steam or boiling water rather than flames from wood blocks for shaping their barrels. It is true that these two techniques are quicker and offer less risk of seeing the staves break during shaping and none afterwards. It was further noted by a number or oenologists that the alcoholic and malolactic fermentation is more difficult to achieve completely in barrels that are two years old or at the time of the second use or filling with wine, even if the barrels have, or have not, been sulfured or slightly sulfured previously, than in new barrels. The same can be said both for barrels on which steam or hot water is used after manufacture as between barrels shaped using the same systems. In both cases, the explanation given is the loss of nutritive substances given up by the barrels and necessary for the yeasts and bacteria. Therefore the comparison between the barrels shaped using flames coming from bringing wood blocks or chips and barrels shaped with the two other systems, the first solution always gives a better aromatic and gustative richness and, at equality of price, the barrels shaped with flames coming from burning wood blocks have a longer life. For example, a number of wine growers of Meursault, Puligny, Montrachet, Chablis or other white wine producing regions and users of Damy barrels who smile in saying: after three years' use Damy barrels continue to offer the same type of aromas and tastes. The same goes for the Billon barrels with certain delicate red wines.

Today, from an international and legal point of view, only barrels are authorized to bring aromas and taste to wines.

Barrels are products offering a whole variety of aromas but which are also very expensive. It is therefore a pity to loose prematurely, voluntarily or not, during manufacture, an aromatic and gustative potential. And some of our most important customers world wide have informed us that they no longer want the barrels to be tested with water before delivery, but just to have the tightness tested with compressed air, so as to be able to preserve all the fragrances and aromas of new wood. Therefore, so as to be sure not to loose any aroma or fragrance we only use compressed air for them.

Prices. Prices. Prices

The largest production of French barrels is found under the appellation viticole of Cognac in the Southwest of France.

A brandy produced in Cognac can only use the name of Cognac if it is produced using a wine with a Cognac denomination and also aged in a French Oak barrel.

For a number of years, the production and sale of Cognac had been trending downward. In addition, harvests of various grape varieties throughout France and the rest of Europe were experiencing a qualitative development that was, at best, irregular.

The viticulture market of a number of different countries had thus been in a downward spiral. This crisis in the reduced demand for wine and Cognac directly affected the barrel market for many French cooperages, who suffered a significant drop in the sale of barrels.

As a result, many French coopers reduced, or kept at a minimum, their stocks of wood.

Recently, however, there has been a steep rise in the demand for Cognac from Asia and the production and sale of Cognac has risen accordingly. Moreover, we have seen an increase in both in quality and quantity of wines in certain regions of the world.

Consequently, the demand for French Oak barrels has started increasing again and many French coopers have therefore tried to build up their stocks of both new and aged French Oak in order to meet the worldwide demand of for barrels.

As for the French government, it has decided to reduce the volume of sales of wood from the forests belonging to it, therefore causing a drop I n the sale of durmast oak of the quality used for the barrels.

All this explains the general increase in the price of quality wood and therefore the cost of barrels made of French oak.

The French government controls the sale of durmast oak by public auction during which the sale price is introduced at its peak (and gradually decreases if no bids are made). Over the one cooperage in particular has bid first and maintained very high selling price for the wood for no other reason than that of wanted wanting his name to appear, year after year, in the publications of the wood industry in France, for the purpose of showing his financial capacity.

Furthermore, other cooperages who also require wood to increase or rebuild their own stocks, take part in maintaining these high purchase prices. Unfortunately this results in the high price of wood used by all the other public and private sellers of durmast oak.

In the cooperages of Burgundy, with our own barrel manufacturers, Damy and Billon, which have been in business for more than three generations and which are members of the association C.T.B., we also require high quality French wood that we buy at market prices. Our purchase prices for raw materials are not the highest for the following reasons:

  • Today, our two Cooperages (Billon et Damy) have had for many years a constant annual production of barrels of 33.000 to 38.000 barrels made of French durmast oak. That is why we have a permanent need for wood and our forecasts for purchasing wood are established several years in advance on needs. Similarly, so as to have a greater autonomy with regard to quantity, quality and price, our two Cooperages are the whole or partial owners of two stave manufacturing units. The rest of the supply of staves comes from independent producers bound by strong family links to Damy and Billon.
  • The facilities of Billon and Damy are situated close to prestigious French forests: Allier, Nevers, Bertrange, Burgundy, Cîteaux, and Vosges. This allows us a better control of the quality, supply and, assuredly, at present, an advantage on the cost of transporting rough and finished wood, therefore an economic advantage on the transport from the facility to Italy.

Faced with this situation, the Cooperages of Burgundy and their direct agents, in this case Bouchard Cooperages, have used their best endeavors to guarantee a constant high level of quality and to maintain the price of barrels within limits that fully satisfy the customers.

Quality. Quality. Quality. Control

For several years now, Vincent Bouchard and Bouchard Cooperages, in cooperation with the American Bureau for Oenological Analysis and Research – (E.T.S. in St. Helena (CA), have been trying to find perfect a method for taking samples of barrels in order to submit them for quality control analyses. The purpose of such analysis is to assess the quality and consistency of the toasting of the barrels, as well as the quality of the heating of the staves by immersion.

Now that we have successfully developed a method for collecting samples during production in our facilities, we have created a new company, Oeno-Bois Recherche Conseil, since May 1st, 2008. This company is a partner of Tonnellerie Billon, Tonnellerie Damy, Bouchard Cooperages and the Research Manager, Charles Rossignol, Doctor of Oenology, Viticulture and Food Processing engineer.

Dr Charles Rossignol is not only charged with the frequent and systematic control of the production to analyze the quality of all the products we offer our customers, but at the same time to legally follow the supply of wood in accordance with the C.T.B. standards so as to prove the geographical origin of the French woods used by the Damy and Billon cooperages. Furthermore, for the sampling, Dr Rossignol analyzes directly in the forest and wood storerooms the durmast oak used and establishes the origin of the wood, the amount of ageing and also the possible risk of contamination of the wood itself.

Therefore, to sum up, not only do we offer our customers the fairest market prices for our barrels, but we also guarantee the quality and forest origin of our French oak, as well as its traceability.

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