When Laurent Lozano was interviewed for a position with the Hennessy Tasting Committee a couple of years ago, he was blindfolded and asked to taste a selection of the famous cognac house's eau de vie (water of life). He took a whiff of the samples, rolled them round his mouth then spat them out - with one exception. When Lozano, a highly qualified oenologist and agronomic engineer, took a mouthful of what turned out to be Richard Hennessy, the house's finest and most expensive blend, he felt compelled to swallow. This, it would appear, sent the right message to the members of the panel. He got the job. Now Lozano spends most of his time in Cognac, monitoring the development of Hennessy's vast collection of eaux de vie and assisting master blender Yann Fillioux in combining them. Every now and again he is sent out to conduct brand-education programmes for Hennessy's distributors and, increasingly, for customers. While in Hong Kong recently he conducted a blending session at the Mandarin Oriental hotel, where selected customers were given the opportunity to create their own blend from three vintage eaux de vie: 1970, 1978 and 1983. It was a fascinating exercise, demonstrating primarily how fiendishly difficult the blending process is. Having gone through a similar tutorial with Lozano during a visit to Cognac a year ago I was not surprised, but experience, it seems, taught me nothing. I fear I fared no better than the first-timers. Blending should be simple: each eau de vie has its own personality. The 1970 had a hint of cedar and vanilla, the 1978 was notable for its floral aromas and the 1980 was a big, forceful spirit with a pronounced citrus character; but in what proportion should they be combined? I settled for 35 per cent of the 1970, 43 per cent of the 1978, and 22 per cent of the 1983, and although Lozano was again unfailingly polite, he did not swallow. Making sense of a blend of three cognacs is exceedingly difficult, so imagine what Lozano and his colleagues go through in making Hennessy's deluxe blends. More than 100 eaux de vie go into Richard Hennessy, some of which are more than 200 years old, and several hundred, aged 25 to 130 years, are required for Paradis Extra. Even the simplest of cognacs in blending terms, Private Reserve, a re-creation of a blend first assembled in 1873, contains 14 eaux de vie from specific vineyards owned by the Hennessy and Fillioux families. The art of blending seems to be in the blood. Seven generations of the Fillioux family have blended Hennessy's cognacs since 1770. I know how I rate on nose and palate, but something may still be salvaged. At the end of the tutorial each novice blender was invited to create a 50 centilitre bottle of their own 'private reserve', labelled with their name and the date. If requested, Lozano would sign the bottle. I have drunk almost all my own blend, but I happen to have a full bottle of Yann Fillioux's. Surely there could be no harm in decanting a little into the empty vessel bearing my name? It would be such a shame to waste the bottle.