Wooden Casks or Vats for Wines and Whisky
Wines are spoken of as being ‘in wood’ when they are in either a wooden cask or vat, prior to being bottled. The length of time they are kept in contact with wood in some form can influence them considerably, as is obvious when you think that wood is porous and the wine or spirit can both receive air and give itself out by evaporation when in a wooden vessel. The contribution of the cask can be great, as witness the use of sherry and other casks for the keeping of whisky and whiskey. A skilled blender can often detect what type of cask a sample has been drawn from simply by nosing.
Certain wood is unsuitable because it is too porous; other woods can impart too assertive a smell and flavour to the wine or spirit – chestnut, for example, can often affect the liquid disagreeably, although with care it can be used. Oak, of a particular type, is probably the ideal. Until recent times, the best casks were often of Baltic oak, but now supplies often have to come from the U.S. experiments have been made in Cognac to try to see whether Limousin oak or Troncais oak is most satisfactory. Some of the great Bordeaux estates put their new red wine into ‘new wood’. This means new casks, previously seasoned, which will give immediately of their various attributes to the liquid kept in them. In the Rioja region, an enormous difference is made by the length of time a wine is kept in wood. Some stay in their casks for 4 years or even more, and this imparts a particular style that may or may not be liked by the individual drinker.
In the past, it was a hazard that a wine might be ‘woody’, smelling and tasting flat, soggy and altogether dreary; although this could sometimes be a transient stage through which a wine would pass during its normal maturation. A defect in a stave in a cask could convey this unpleasant woodiness, as compared with the pleasant style often associated with a matured wine which has been ‘in wood’ for the appropriate time.
The cost of casks, however, makes present-day supplies both expensive and difficult to get. The same applies to wooden vats, which are naturally difficult to keep in prime condition and to repair. Coopering is a declining trade; although some large firms do keep their own coopers to maintain and repair casks and vats.
For some time, the use of stainless steel, enamel and glass linings, or special concrete has been appreciated for the keeping of wines, especially white wines. The latter please by their fresh, crisp style if they are of the dry type and therefore exact control over their development is essential if they are to compete in international markets. The light ‘star bright’ dry wines of today frequently never go into a wooden container at all. This can also apply to many of the inexpensive or small-scale red and pink wines. These would gain nothing by maturation in wood and risk deteriorating or going out of condition unless kept in vessels that can be cleaned so that no possible danger of infection can lurk in them. The great red wines of the world, some of the sweeter whites and the fortified wines have an additional resistance to infection and the use of wood in making them can be an advantage. However the maintenance of the traditional vessels is costly and time-consuming.
Sometimes, a wine that has been kept in a vat made from stainless steel or concrete, may be given a few months’ in a wooden vat prior to being bottled, just so that it can assimilate the contribution of the wood. There are even stories, that may be well-founded, of some very advanced wineries using special wooden chips in their vats, or even a type of’essence of wood’, so as to simulate the effect of a wooden cask or vat on the wine. There seems nothing amiss about such a procedure; although it is perhaps more interesting for the student to be able to compare a wine that has been in wood with a similar one that has not, and see which appears preferable.
There is a misunderstanding in the minds of many people about the supposed superiority of, say, a red wine that has been kept in wood for a long time. It is naturally up to the individual winemaker to select a vessel for the wine that will be satisfactory, not too expensive to use, and that can be maintained without too much trouble: different wines obviously need different treatment. But wine kept in wood will not necessarily go on improving, any more than a wine in bottle. Exposure to the air, which is inevitable as the contents of a cask evaporate and the level goes down, can have a bad effect on even the finest wine. This is why casks in a sherry bodega, a port lodge and in the great red wine cellars of Bordeaux and Burgundy are kept topped up, so as to leave only a very small space for the air to affect the wine before it is bottled. Of course, in the past, the great red table wines were often kept in wood for much longer than they are nowadays, but they had usually been made differently in the first place, probably had far more tannin (the hat being left in the must for weeks rather than days, as happens now) and they matured more slowly. Today’s economic pressures do not permit this and it is important to bottle a wine before it gets tired and oxidised, while it is still full of vigour and is ‘making itself.
If you are in a wine region and visit a small farm where the owner makes wine, you may be offered a sample from a cask in which the wine has remained until it is required for domestic use, when some will be drawn off into a bottle, just as used to happen hundreds of years ago. It is unlikely that you will enjoy this type of wine as much as something that has been bottled according to today’s expertise – although naturally such a wine is always interesting to try.