A tasting this week at Roberson in London of the current releases from Champagne Ruinart together with a short vertical of the vintage Dom Ruinart Blanc de Blancs included a fascinating comparison of the 2004 from bottle and magnum.

The style of the Ruinart Blanc de Blancs is quite deep. Indeed, when the tasting started with the “R” de Ruinart Brut and the nonvintage Blanc de Blancs, it seemed to me that the “R” had more of that crisp brightness I expect from Blanc de Blancs, whereas the actual Blanc de Blancs was deeper and nuttier. The vintage Blanc de Blancs follows the same profile as the nonvintage, but with greater intensity.

The 2004 from bottle shows lovely aromatics leading into deep white flower and citrus fruits on the palate. Nutty overtones give a mature impression that extends into slight suggestions of brioche. Overall it is deep but lively. The magnum offers less obvious aromatics and the most immediate difference in impression is a distinct touch of bitterness on the finish. The difference narrows with time in the glass, but the magnum continues to offer more obvious sense of texture and structure. (This did not produce any evident preference among tasters, some of whom preferred the bottle, others the magnum.)

Conventional wisdom holds that magnum is the ideal format to age wine; because the neck of the bottle and magnum are essentially similar, the greater volume of wine in a magnum has less exposure to oxygen (both initially in terms of the airspace in the bottle, and with time as oxygen enters through the cork). So if anything you would expect a magnum to age more slowly, and in the case of Champagne to appear fresher than a bottle, but this was not the case.

The house style at Ruinart is extremely concerned with oxidation. “Freshness is the golden thread of the house,” says Amelie Chatin of Ruinart, who came from Reims for the tasting. “To achieve our signature freshness we have a reductive winemaking process. For crushing we use a pneumatic press, not the traditional basket press. And there is no wood, everything is fermented and matured in stainless steel. Fermentation is at low temperature to maintain aromatics. Every stage is important, including our special shaped bottle, which has a narrow neck to admit less oxygen.”

I could attribute the effect of the magnum versus bottle more easily in terms of oxidation if we were dealing with red wine. In that case, I would assume that exposure to oxygen had softened the tannins in the bottle, but not yet in the magnum. That’s a more difficult explanation for Champagne, where every effort is made to limit skin contact (where the tannins originate) in winemaking. My companion, the Anima Figure, thought the magnum showed tea-like aromas, which would certainly be consistent with some effect relating to tannins.

At this point in time, I preferred the liveliness of the bottle to the bitter structure of the magnum, but I’m certainly curious as to whether the effect is actually due to a difference in rate of aging, in which case in due course the bottle may appear tired when the magnum is fresh. (The difference was not due to time of disgorgement. Magnums are often disgorged later because they age more slowly, but in this case both bottle and magnum were disgorged more or less together, about 16 months ago.) I hope to be invited back in, say, five years to reassess the situation.

Given the impression that the bottle is just on the point of developing toast and brioche, I would normally assess potential longevity at around another five years, but the next wine was the 1998, from bottle disgorged after 9 years in 2007, which is only a little tertiary. Blanc de Blancs here shows not with crisp freshness but in the creaminess of the palate, which is moving in the direction of toffee and caramel. The point about difference between bottle and magnum was perhaps made sideways on by the next wine, a 1993 magnum, disgorged after 10 years in 2003: this was more developed, certainly, with faint mushrooms and other tertiary notes, but it seemed more to have greater intensity of  butter and caramel on the palate than to be as much as five years older than the 1998. Another light on changes in Champagne, incidentally, comes from dosage, which has effectively halved over a decade: 10 g for 1993, 7 g for 1998, 5.5 g for 2004. (Amelie says it may go back up a bit in future). There is a really clear lineage of development from 2004 to 1998 to 1993 which identifies Ruinart’s style for Blanc de Blancs as complex creaminess. Anyway, the 2004 may go longer than I thought at first, but more tastings are needed to assess whether to go with bottle or magnum. I am always available.