By 11 am on Friday morning, August 30th, the temperature had already reached 33ºC at Malvedos. Although we had abundant rainfall in the Douro over the first few months of the viticultural year (i.e. from November 2012 to April 2013), precipitation levels began to fall sharply from May. At Malvedos, just 3.5mm of rain was recorded during the whole month of June, 4mm during July and not a single drop in August, well below average for all three months.
To further complicate matters, air temperatures since the summer solstice and over the last two months in particular, have been rising steadily, with Malvedos registering an average daytime temperature of 28ºC during the month of July and 27.7ºC during August, in both cases that is approximately 3ºC above the mean. Also significant were the maximum daytime temperatures recorded at Malvedos, a sweltering 42.3ºC (July) and 42.6ºC (August); for those readers who think in Fahrenheit — that’s 107 degrees…
The Portuguese Meteorological Office advised that the heat wave registered between the 3rd and 13th of July, which affected the whole of the country, but particularly its north-eastern corner (where the Cima Corgo and Douro Superior sub-regions are located), was the “most significant” (a euphemism for ‘severe’) observed since July of 1941 (July 2006 also came close).
Our vines have therefore been subjected to a double onslaught of hydric stress and thermal stress and they have had to ‘batten down the hatches’ to withstand these challenging conditions and thus far they have done this incredibly well. The accumulated water reserves (from the winter/spring rainfall) have made a real difference and our older vines (with more developed root systems that go deeper into the soil) have fared very well. Whereas the younger vines with their shorter roots, have struggled to tap into the moisture, which inevitably retreats lower down into the schist soil as the drought has depleted the water reserves.
As the Malvedos viticulturist, Alexandre Mariz pointed out, however, it is quite remarkable how well adapted these hardy vines are to their tough environment; the grape clusters and berries are looking well formed and healthy. The size of both the grape bunches and the berries is quite small, a telltale sign of quality (concentration as opposed to volume). Despite the difficulties, the vines at both Malvedos and Tua are looking very healthy, the only signs betraying the lack of rain and high temperatures being the parched brown vine leaves along the lower sections of the plants, with some of them already falling off the vines. This is one of the vines’ self-defence mechanisms when faced with such trying conditions; the vine sacrifices part of its leaves to lessen the pressure on the plant, which has less water to continue the maturation cycle. It is the lower leaves that are shed, partly because they are closest to the hot soil surface, which radiates heat back up towards the vine but also because the vine preserves the mid and top layers of leaves in order to provide the all important shade that the grape bunches require to shelter them from the fierce sunshine.
Stop press: on Thursday morning, September 5th, when this post was about to be published we awoke to a real surprise at Quinta dos Malvedos; during the middle of the night, a thunderstorm rolled in and delivered a bounty of rain: about 10mm, which came down steadily over around three hours, according to our caseiro (farm manager), Senhor Arlindo, who was woken up by the thunder and witnessed the downpour. Dominic Symington who was at Malvedos entertaining some Russian guests from our importer there, had a broad smile of contentment. He was later joined at the Quinta by Charles Symington, our head winemaker, and he too was all smiles. Charles is in no doubt that this welcome rain has made a real difference and that the final stretch of ripening has been given just the fillip we were praying for. We still do not have a firm starting date for the harvest but Charles says it will be later than usual (up to 10 days) and will probably start during the third week of September.