Here is proof, if it were needed, that dry Loire Chenin Blanc ages wonderfully well. Although it is unlikely to last as long as the sweet wines, well made wines can last decades. On Sunday I opened this 1964 Saumur from the late Henri Aupy's Clos de l'Abbaye on the northern edge of Le Puy Notre Dame. Henri Aupy established the domaine in 1962. His 1964 is now mid-gold with a touch of aged maderisation along with dry honey on the nose. This touch of maderisation adds extra complexity to this still quite austere wine preserved by its backbone of vibrant acidity. No reason to doubt that this 1964 will last at least another decade or two. The weak point is likely to prove to be the cork.

I was born in 1964 ....

The domaine is now run by Henri's son, Jean-François. I visited the domaine on at least a couple of occasions during the 1990s but haven't been back for years. Not a criticism of the wines but a question of time. I must try and go back.

Henri Aupy was one of the architects of the recently recognised (October 2009) AC Saumur Le Puy Notre Dame, which is for red wines only. Aupy started the campaign in 1975. Whether he envisaged that the new appellation would cover not just Le Puy Notre Dame but 16 other communes as well is another matter.

Part of the view from the Decanter tasting room: chimney of Tate Modern and St Paul's

The biodynamic calendar is divided into four types of day – leaf, fruit, flower and root. Wine is believed to taste at its best on fruit days when it will be more expressive and less well on the other days.

Over the last two days I have been involved in a Decanter magazine tasting of Saumur red, Saumur Le Puy Notre Dame and Saumur-Champigny. Like the rest of the panel I was looking forward to tasting some lovely wines. Sadly many of the wines we tasted yesterday were very disappointing, closed up, tannic and lacking charm. Having tasted a number of delicious 2009s recently I was very surprised.

After the end of yesterday's tasting – we assessed between 30 and 35 wines, I went on to the Charles and Philippa Sydney's Loire tasting at the Royal Society of Arts. Here the whites, especially 2010 Muscadets and various 2010 Sauvignons were showing well. The reds, however, which included some wine that I had tasted very recently and liked were as dumb as the reds from Saumur in the Decanter tasting. This was confirmed by Charles Sydney who wondered where all their fruit had gone.

A plausible explanation arrived this morning as it was immediately obvious that many of the remaing wines were showing much more attractively today than yesterday. Tasting over we discovered that today was a fruit day. Whether this was the factor or there were other atmospheric changes or changes of pressure, etc, I'm not sure. However, the wines generally tasted better today. Did the wines change? Did we? Or did both change?