Let me try the impossible and be brief.
Problem number one: we don’t use a pressure bomb to determine water stress. Of course this means that small differences will be difficult to detect.
Solution one: the rate of shoot growth (determined visually with almost weekly vineyard visits and by the number of times hedging was required) can be used as a good proxy for water stress when temperatures are in a normal range for growth.
Problem number two: I didn’t do any measurements over the last three years, just observations. Again this means small differences will be difficult to detect but since the rainfall amount was so drastically different I think it is safe to assume that differences were such that visual detection was obvious.
Solution number two: my objectivity. You’ll just have to trust me here. I can be objective to a fault. Just ask my wife; sometimes in a discussion I point out how she can better attack my arguments though I eventually end up in a disturbing argument with myself. OK, so I don’t go that far.
The previous paragraph alone should hint at my objectivity. I am such a nerd that I want you to be aware that I am aware of the subjective measures by which I am drawing these conclusions and yet I feel they are still solid. Actually they are common sense if you are up with current viticulture literature or understand – as Principles and Practices puts it – famous, high-quality wines often come from vineyards with relatively low fertility (read vigor).
After working with this vineyard for 4 vintages I have concluded that it is one such vineyard. Quite simply, the greatest quality gains this year were in the blocks that had the potential for the greatest devigoration from early water stress. And as per the previous paragraph this was evidenced by slow shoot growth that required NO hedging in blocks that typically require 1, 2, or 3 hedging passes.