You might think that once a wine has gone through alcoholic and malolactic fermentations, and been matured for months in oak barriques, that the die was set. Not a bit of it: the continuing experiments at Chateau Margaux show that there is an effect from every stage of what I suppose you might call finishing procedures. “Once again it is impossible to deny the differences, which is somewhat frightening,” was Paul Pontallier’s comment at the end of the tasting.

Once simply part of the routine of producing red wine, fining has become somewhat of a controversial issue, and is now one of the most obvious differences between Old and New World. When I was discussing Cabernet Sauvignon with producers in the course of researching my book Claret and Cabs,  virtually every producer in Bordeaux told me they fine, and almost all producers in Napa Valley said they avoid fining just like filtration.

Fining was introduced as a procedure to lighten the wine, the traditional process being to add egg whites to the barrel. Albumin protein in the egg whites is positively charged, and so reacts with negatively charged tannins to precipitate them. The conventional argument is that this softens the wine by removing harsh tannins and also polishes it by taking out other components. Critics ask why the egg whites should act only on harsh tannins and take the view that desirable tannins and other components might equally well be affected. And, of course, over the past ten or twenty years, tannins have become much riper so you might well ask whether they still need to be removed. (Most producers who continue to find do use fewer egg whites now than they used to.)

Well, the answer at least in the context of Bordeaux, is absolutely clear: the 2004 Chateau Margaux fined with 6 eggs tasted like a completely different wine from the unfined example. Some people thought they could see a difference on the noses of the two wines, but personally I thought they were indistinguishable (and I am a bit hard put to see why volatile compounds might be removed by fining). But the unfined example had more evident tannic grip, less finesse, and came up just a little shorter on the finish. The fined sample simply gave a distinctly more polished impression, not just because of less tannin, but with a sense of being altogether better rounded. Chateau Margaux as you will find bottles in the shops, by the way, has been fined with 5 egg whites per barrel since 1996.

Filtration seemed to have less effect, as tested by comparing unfiltered Chateau Margaux 1995 with sterile-filtered wine. There was no detectable difference on the nose, and the balance on the palate seemed very similar. The main effect to my mind was that the sterile-filtered example seemed like a slightly older, more developed wine, with a touch of sous bois that was not evident on the unfiltered wine. Most participants preferred the second wine, but that depends somewhat on whether you prefer your wines younger or older. Paul Pontallier felt that the filtered wine had actually deteriorated a little due to a touch of oxidation. I can’t say that I would describe the filtered wine as eviscerated or having lost character as a result of filtration, but I suppose it might be the case that the filtration removed components that protect against oxidation.

The closure trial compared Pavillon Rouge 2002 sealed with natural corks with the same wine sealed under screwcaps. There had also been a trial with synthetic corks, but apparently the results were disastrous, and in relatively short order the wine was spoiled. “It’s a good decision to use screwcaps for white wines that will be drunk in the first six months,” says Paul Pontallier, “and with what I know now I would do the same, but our dilemma is that we want to make wine that will age.” The two wines were quite different: open, round, and fruity under cork, but reserved, backward, and showing more austerity under screwcap. Interestingly, the participants split more or less equally as to which style they preferred.

Chateau Margaux is just about to undertake the construction of a new experimental cellar that will allow them to undertake even more experiments. Among future projects are looking into the properties of individual clones of grape varieties and investigating the effects of different types of pressing. “To my astonishment, many people take the view that, if it is new, it must be better,” says Paul Pontallier, “I admire their optimism, but I feel the need to experiment first.”