‘We would prefer God to decide,’ says Almaviva winemaker
Such is the complexity of irrigation management in Chile’s Maipo Valley, Almaviva’s head winemaker, Michel Friou, would rather leave the decisions to God.
Speaking at a tasting of Almaviva vintages dating back to 1998 during Vinexpo Bordeaux in June this year, Friou said that the issue of when to water the vines, and how much to give them, was his greatest ongoing challenge at the estate, which covers 60 hectares in the Maipo’s sought-after sub-region of Puente Alto.
Having considered the topic of irrigation at the property, which is the result of a joint venture between Baron Philippe de Rothschild and Viña Concha y Toro, he said, “Sometimes we would prefer God to decide for us.”
Although the average annual rainfall at Puente Alto is 340mm, Friou recorded significant variation in the yearly totals over the past 20 years, with precipitation ranging from 730mm in 1998 – which is similar to the level in Bordeaux – to just 85mm the following year.
Over the five year period from 2011 to 2015, he said that average rainfall totals had amounted to 230-240mm, which would class Puente Alto as a desert – an area generally defined as receiving an average annual precipitation of less than 250 mm.
However, Friou stressed that Almaviva’s issue was not gaining access to water, but how much to use, and how often.
“We have a 250 metre deep well, which is probably the deepest in the Maipo, and we have rights to water from the Andes, so we have water,” he said.
Continuing, he recorded that in those rare years when the region received more than 500mm of annual rainfall (1998, 2001 and 2003 – see bar graph), then, in some ways, his job was easier, as he can leave the irrigation patterns to nature.
“If we have more than 500mm then we can leave nature to make the decision for you, but if you don’t have enough rainfall then you have to make the decisions yourself, and that is more of a challenge,” he said.
Continuing, he explained that he has tried different frequencies and quantities, before admitting, “I still feel that we have not found the key to make the best decisions… you have to be sure that you add enough water, but not too much.”
Interestingly, he also said that the water in the form of rainfall was much better for the vineyard.
“If it rains then the whole surface of the vineyard is watered, which is completely different from adding water locally,” he said, noting that irrigating the vines means that “a large part of the soil never receives any water”.
In short, he said that irrigation water is “never as good as what we get from the rain.”
Explaining further this statement, he told the drinks business that he believed the difference was connected to the positive impact of rainfall on the microbiological life of the vineyard soils, as opposed to irrigation, which only wets a localised area.
Exacerbating the limited, if focused impact of irrigation on the Almaviva vineyard, Friou said that all new plantations at the estate since 2002 have been made with an underground watering system.
Using “dripping lines” at 80-90cm below the vineyard surface, the water is added deep within the soil to encourage the vine to root downwards.
And, while Friou said that he would prefer to leave the watering decisions to nature, he also stated, “If we didn’t irrigate in Puente Alto, the vines would die.”
Meanwhile, during a masterclass on Almaviva at Vinexpo Hong Kong last year, it was pointed out the soil is Chile is slightly alkaline because irrigation water has a lot of calcium, so, while Almaviva’s soils are based on volcanic rock – and therefore don’t contain calcium – the wines have “a grippy kind of acidity”, which is credited to both the large diurnal temperature shift in Puente Alto, but also the calcium content in the irrigation water.
As part of the tasting, Friou compared the rainfall totals and patterns, as well as the temperatures, of famous Cabernet-producing parts of the world: Pauillac in Bordeaux, Oakville in Napa, and Puente Alto in the Maipo – and the comparisons can be seen over the following pages.
Almaviva was established in 1996 by Baron Philippe de Rothschild of Château Mouton-Rothschild and Concha y Toro. Their aim was to create the first Bordeaux Grand Cru Classé equivalent in in Chile using grapes from the best Puente Alto vineyards. Of course, in Pauillac, where Château Mouton-Rothschild is found, the amount of water each vine receives is always decided by nature, because irrigation is not allowed. Nevertheless, with an annual average rainfall of 874mm, which falls throughout the year, the vineyards of Pauillac rarely suffer from water deficiency.
Comparing the position and climate of famous Cabernet-producing parts of the wine world in France, California and Chile (above and below).
Oakville and Pauillac may have the same quantity of rainfall on average annually but, as the bar graph above shows, the distribution of that rainfall is totally different: in Pauillac, it rains almost every month, but in Napa, the rain mainly falls in the winter and spring, leaving the rest of the year dry. Meanwhile, in the Maipo, irrigation is necessary to keeps the vines alive.
A comparison of temperature highs and lows in the three regions shows their similarities, although Napa has the highest average summertime peak, and Puente Alto, which is situated beneath the Andes mountains, the lowest.
The characteristic features of Puente Alto include its stony soil, cold, rainy winters, and the hot days and cool nights of its summers.