But fortunately for wine speculators there are some things you can tell even when the grapes are still weighing heavy on the vines. By midAugust you know about the health and the size of the crop. Through a combination of chemical analysis and old-fashioned tasting, you can also tell what ripeness levels are like, and whether that crop will be picked sooner rather than later. In recent years, early (and rich) pickings have not been unknown. Hotter summers mean earlier picking, since the grapes ripen earlier than they used to. That sometimes . . . but not necessarily . . . leads to better quality as the heat produces really ripe grapes.

And this seems to be the case in parts of Italy, such as heat- and drought-afflicted Tuscany.

In general, berry size tends to be smaller in very hot years. That means there is less wine per hectare . . . but the grapes should, in theory, be more concentrated with flavour-forming compounds. That appears to be the case in Chianti.

Will this produce the vintage of the century? Nobody knows, but there are similarities between this summer's heat and that of 2000 and 2005 in Bordeaux . . . and both of those were outstanding vintages.

If the predictions turn out to be true, the estates that always make outstanding wine will make awesome wine and the estates making reasonable wine will make much better wine. But remember:

nobody knows anything . . . yet.

CHIANTI
Selvapiana

This lovely estate in the Chianti Rufina district was once a summer home for the bishops of Florence.

Today it's a large producer whose wines are almost overshadowed by its wonderful extra-virgin olive oil . . .but wide availability makes it a good name to look out for.

Badia a Coltibuono

The Coltibuono estate was home to an abbey where the monks made some of the earliest wines known in Chianti. Though they make one ultra-premium wine called Sangioveto, they are more commonly known for their good Chianti Classico.

Fontodi

A family business, on an estate in Panzano, revived in the early 1980s by Giovanni and Marco Manetti. The vineyards lie on a curved slope called the Conca d'Oro, or golden shell. The wines are worth their weight in gold, both the basic Chianti Classico and the top-of-the-range Vigna del Sorbo.

Fattoria di Felsina

Felsina inhabits an estate called Grancia that's at least 800 years old but it's greatness dates to the early 1980s, when the owner's son-in-law took over management. Fontalloro and Rancia are the two top wines.

Isola e Elsena

One of the great stars of Chianti, an immaculate pair of estates combined and transformed 30 years ago by Paolo di Marchi. Their top wine, Cepparello, is consistently ranked among the top 'Super Tuscans' operating outside the official Chianti classifications.

BORDEAUX

Chateau Leoville-Barton

One of the most famous names in St-Julien and one of the most typical exemplars of the area's character. A second-growth wine in the official classifications, it often behaves like a first growth.

Chateau LeovilleLas-Cases

Another secondgrowth star of StJulien, and outperforming extravagantly in recent vintages. Their 2005 vintage was generally regarded as one of the stars of that great year . . . which means prices are now astronomical.

Chateau Palmer

A third-growth Margaux property in the 1855 classification of Bordeaux, Palmer produces wines that most people would rate higher than that. Situated next door to the famous Chateau Margaux, it makes wines that are now fiercely expensive . . . but unforgettable.

Chateau Rauzan-Segla

Another exceptional Margaux estate accorded second-growth status and now living up to the reputation after some years of underperformance through the mid-1990s. Its wines are less expensive than those of Palmer, even though it's officially ranked higher.

Chateau SociandoMallet

This fantastic wine is classified as nothing more than Cru Bourgeois Exceptionnel, rather than a classed growth, but its quality shows the classifications don't always mean much.