So if we must put up with the frost there must be some reason to grow grapes in the brass monkey country…
The vast majority of vineyards in the world are grown between the temperate latitudes of 30° and 50° with warm to hot climate grapes typically produced from the lower latitudes and Cool to Cold climate grapes produced in the higher latitudes. The latitude of Orange is 33° which would make it quite a hot region if it wasn’t for a little volcanic disturbance a few years ago that now sees its vineyards perched at quite high altitudes. High altitude vineyards are special and there is some good science behind it.
For every elevation increase of 100 meters there is a temperature decrease of 0.6°C and a corresponding increase of one percent Ultraviolet radiation. High altitude puts us closer to the sun with less of the earth’s atmosphere to filter out ultraviolet light.
As a result we need to liberally apply SPF30+ but grapevines handle this quite differently, they thicken up their skins and modify the berry skin chemistry to protect against sunburn. This gives grapes grown at high altitude in this sun burnt country a decided advantage because most of the flavour in wine is derived from the grape skins
Another advantage of high altitude vineyards is the high difference in day/night temperature. During the day the grape accrues carbohydrates via photosynthesis in the leaves, then at night during respiration the vine borrows back from the berry some of these stores. The lower the night time temperature the less the vine needs to borrow during respiration resulting in more intensity in the grapes.
Interestingly Mendoza Argentina that is also at 33° Latitude. One grower there, Bodega Catena Zapata, is leading the research in high altitude viticulture and they are producing some of the best Malbecs in the world from their high altitude vines. They’ve noted that sunlight intensity in the high altitude vineyards has a great effect on the aromatic profile of Malbec as well as the concentration of tannins.
While there are vineyards in Mendoza at more than 3000 meters the limit in Orange is about 1100 meters above this it becomes too cool to ripen the grapes. There’s something called the Massenerhebung Effect that relates the height of the adjacent mountain to the zonation that occurs at lower altitudes. So if you have the Andes (6980 meters high) next door you can grow grapes higher then you can on the slopes of Mount Canobolas (almost 1400 meters high).
During ripening stages the temperatures in Orange are quite cool slowing down the photosynthetic carbohydrate pump resulting in grapes maturing to full flavour ripeness without becoming over sweet which produces full spectrum, complex wines without high alcohol.
So despite higher risk, increased cost and typically lower yield high elevation grape growing is definitely worth the challenge because I am driven to produce the best wine I possibly can.
Gerald – the long winded wine maker.