I realised a life-long ambition last week – to learn to prune a vine. It is a very important step in the life cycle of the vine and determines how many bunches of grapes will be produced.
The sun beat down on the old knarled Cabernet Sauvignon vines. The idea is to leave a ‘cot’ which will become next year’s fruitbearing arm the closest to the ground as possible and cut it short leaving one bud. Then to find an ‘aste’, which will be the arm that will produce this year’s fruit. It needs to be able to be easily bent in the direction of the row and is the lowest to the ground after the ‘cot’. You leave six buds and cut the seventh off and cut the branch after that. The ‘women’ then go through the rows pulling out the dead wood and bending (plier) the aste branch down onto the wires.
The dead wood is cut away leaving the vine stump with its very short ‘cot’ of one bud and the longer six bud ‘aste’. This system is Guyot Simple. If you have two ‘astes’ two arms than the system is Guyot Double and you leave two cots for next year’s fruit too. You still have the same number of buds ie three or four on each ‘aste’.
All pruning has been pretty much completed in Bordeaux as the weather is heating up (early 20s) and the sap which resides in the roots of the vine during the winter months is coming up into the plant itself causing the vine to weep (le pleur) when it is cut.
Cutting the branches back short limits the number of bunches of grapes that the vine will produce. More concentration in fewer grapes. This is the goal. It is less wasteful to do this by pruning rather than by green harvesting in the Summer where the excess and late maturing bunches are removed. The only problem with limiting the production at the early stage of the cycle is if there is a late frost. Last year there was a frost on April 6th which damaged buds and was a factor which lead to the low yields in 2008.