|
What the hell is "terroir manipulation" I hear you say? I first used this term back in 1998 at a seminar I gave on Sauvignon Blanc. Its based on the theory that for any terroir to express itself human intervention must occur. The great terroir's of the world do not express themselves without intervention from the human hand, and more so the heart. French appellation law in many cases prescribes how you can manipulate terroir by things such as yield management and pruning technique yet strangely enough does not allow irrigation. In some seasons, even on those very clay rich soils, even these great French terroirs would make better wine with irrigation used scientifically and with the wine in mind. In the Gimblett Gravels Winegrowing District , terroir manipulation is part of the vignerons art. Without irrigation vines would simply die without producing a grape on most of these sites. We have no clay for holding water to speak of. With the modern, scientific winegrowers approach to irrigation, we can measure very accurately how much water is available to the vine and give them just a little bit to get through the next day or so. They are literally drip fed. In this way we can produce smaller crops than on deeper soils with smaller berries having more flavour, colour and better riper tannins. We can even have a bit of a choice in this effect depending on the time of the season we give our vines this slight strangulation. All of this creates low vigour vines, which when combined with the significant crop thinning that now takes place, advances ripening by sometimes up to 10 days making up for some of that heat that may be lacking in some years. Remember this cannot be done on those deeper soils without the stones or those soils unable to control water availability. I believe the biggest effect of these low vigour vines is on exposing more fruit to the sun. Now for a bit of vine physiology, if you can understand this then you will understand a lot about our terroir manipulation in the Gimblett Gravels Winegrowing District. Remember we need to get warmer grapes, not vines, to get into the climatic zone with all these great regions. For us, warmer grapes mean less herbaceous characters, more colour, more extract, better tannins, less malic acid. For us its what we want. We can get grapes warmer by putting them in the sun. Basically a berry in the shade of a canopy on a 22°C day will be at 22°C, below our desirable 25°C. A berry in the sun on a 22°C day, particularly after veraison when its got a bit of colour, will be at or over 30°C, well above our desirable 25°C. By irrigation and probably some leaf plucking we have manipulated our vine to think its in a terroir that is hotter than it really is. We've manipulated the terroir! This explains when you go around all the good producers in the Gimblett Gravels Winegrowing District that you see a lot of grapes in the sun very early in the season. Many even want to bare all and lay their fruit naked and exposed to the sun for all to see. Who said only Pinot Noir could be sexy! It also explains when you go to regions with much higher maximum temperatures than the Gimblett Gravels Winegrowing District , such as the Napa Valley, you see less grapes in direct sun because if it gets too hot they will produce jammy one dimensional wines with unstable colour. These are two examples. A look at the viticultural techniques in the Gimblett Gravels Winegrowing District will see variations on the same theme of giving the vine a fright and getting those bunches in the sun. Row spacing, vine spacing, clones, rootstocks, yields and picking strategy all have an effect. When you put all the permutations together you get a complex melange of contributions to wine style that help the Gimblett Gravels Winegrowing District area in producing truly ripe fruit from these varieties. This modern terroir manipulation approach has really only been in play for less than five vintages on vines of which very few are greater than ten years old. One might imagine what will happen when the vines get older. Most vignerons practise these techniques in all their vineyards in Hawke's Bay. In the Gimblett Gravels Winegrowing District we are lucky we start with the natural state of our terroir being closer to the ideal . . . those higher temperatures of air and soil, and our soils with little water and their electric blanket effect at night, give us just a bit of a head start which we believe is critical. This is our special terroir and how we make the most of it. Our art as vignerons is matching the terroir manipulation to the vintage, second guessing but still respecting what mother nature will do and being committed to producing the very best that we can. It's using the best science and having a natural feel for the land that allows us to do it. REFERENCES |
|
