People who enjoy vintage port have been warned that yields in the Douro Valley are expected to be down this year, due to a combination of hailstorms and extreme heat.

In the Graham's port blog, Symington Family Estates viticulturist Miles Edlmann said June was a "strange month" characterised by both soaring temperatures and unseasonable coolness.

However, it was the "calamitous" last weekend of the month that caused the most disappointment for the region's winemakers, as a "thermal onslaught" of heat in excess of 40 degrees C burned and desiccated fruit on the vines.

In spite of this, the quality of the 2011 crop is expected to be as excellent as ever, but Mr Edlmann warned that yields will be significantly lower than in a normal year.

Earlier this month, Patrick Schmitt of The Drinks Business described his experience tasting a rare bottle of Taylor's Quinta de Vargellas 1965, saying the wine proved single quintas can hold their own with classic vintage port.