Irrigation usually enters wine discussions via viticultural practices, water policy, regional regulation, or sustainability. But irrigation also shapes what wine tastes like and what we mean when we say a wine expresses the place in which it was grown. Concentration, acidity, tannin development, freshness, alcohol, and texture are influenced by irrigation practices.
So irrigation has a lot to do with our aesthetic judgments about a wine.
Too much water can encourage the vines to produce foliage rather than sending nutrition to the grapes. It enlarges the berries and dilutes flavor concentration while increasing yields. But when the vines get too little water photosynthesis shuts down, ripening is delayed and the fruit lacks intensity. The romantic story told in tasting rooms of heroic vines suffering nobly beneath a blistering sun is misleading. Vines do not become expressive simply because they are miserable. Much depends on the site.
What matters for fruit quality is the kind and degree of stress a grower allows. Moderate water stress can slow the growth of foliage and concentrate flavor. But soil type, root depth, temperature, grape variety, and the vine’s age influence the outcome. A vine in deep clay soil will respond differently from one rooted in shallow gravel during a heat wave.
The fact that irrigation changes the sensory character of a wine, complicates familiar ideas about terroir. I recently had a dry farmer claim that irrigation as an intrusion, a human technology imposed on nature. He argued that dry farming reveals place while irrigation conceals it. But vineyards are already cultivated places. Growers decide what to plant, when to prune, how much fruit to drop, when to spray, and when to harvest. Water is another one of those decisions. The relevant question is how irrigation alters the expression of place, not whether it introduces human agency into an otherwise natural process.
But dry farmers do have a point. No doubt, heavy irrigation can produce high yields and blur distinctions between sites. It can snuff out seasonal variation making wine more predictable. and protect a commercial style from seasonal variation. But on the other hand, irrigation helps preserve acidity during extreme heat and allows fruit to ripen without dehydration. In a warming climate, irrigation often protects regional character and many regions have become so hot they really have no choice but to irrigate.
The question is whether water use responds intelligently to the site or forces the site to conform to a preset wine style. Does irrigation help the vine articulate the season, soil, and local climate? Or does it flatten those differences in pursuit of uniformity?
The problem with treating irrigation as an aesthetic question is that you really can’t tell from tasting whether the grapes were irrigated or not. Only deep, site specific knowledge over time would enable that kind of discrimination. But we needn’t identify the cause of a sensory property for that cause to be aesthetically consequential.
So in a tasting note or an article about a wine, it’s worth noting if the grapes were dry farmed if you have that knowledge. It can be just as consequential as the oak program or the type of yeast used in fermentation.
Dwight- Enjoyed reading your thoughts on dry farmed wines. Like moist vineyard and wine matters it is complicated. My original vineyard planting in 1983 on Bradford Mountain (western Dry Creek Valley, Sonoma County) was set up for what at the time was “better living through chemistry” regular drip irrigations with liquid fertilizer applied (fertigation). Problem was that after 100 years of farming this low fertility, low pH, high Al/Fe soil. The vines grew slowly and took 7 years to reach full production (3-4 tons/acre). When I had to replant following 2006 harvest (due to using AXR rootstock and devastating Eutypa infections), I was determined to amend the soil to give the vine roots a hospitable growing environment, select the most appropriate rootstocks and spacing with the goal to “dry farm”. After replanting (5’X8’ spacing) in the late fall 2007 I installed a drip system in spring of 2008 and irrigated the young vines in 2008, 2009 and 2010. Beginning with 2011 harvest the vines have not received supplemental irrigation. I used to get into big discussions with my French winegrower colleagues claiming since we irrigate “our wines are shit”. I would try and explain to them in northern France it is (was?) a rate year where the didn’t receive late spring/early summer rains, whereas in California we rarely receive rains after early April (or before late October) and the vines don’t know if their water came from the sky or a black tube. Over the years my thinking has evolved. There is another inherently bad about irrigation but irrigated vines want to keep growing (they are vines!) and defer putting the energy into maturing the seeds and creating the aromatics/esthers that attract creatures in the wild to eat the berries (and then go poop out to make new vines). Continued irrigation, especially combined with fertigation create “fat, dumb and happy” vines that don’t go through the same maturation curve that most non-irrigated vineyards experience. For me the key to be able to successfully dry farm. We’ve averaged over 5 tons/acred on our 12 acre, 15 variety planing on Bradford Mountain Vineyard (western hills of Dry Creek Valley, Sonoma). Except for this year where cold and rainy April (after incredibly warm and dry March) caused horrible set and major shatter we got 50% of an average crop. I’ve found the key to successfully dry farming is soil organic matter and soil structure. In order to dry farm I have to do a light spring cultivation to incorporate the cover crop residue (beans, vetch, peas, oats and barley), break up the soil capillary action and the fall application of compost (6 tons/acre broadcast). As long as we receive around 25” or rain in the winter (50 year average is 48+’) the soil is deep enough and has the ability to hold/release the water the vines need to keep leaves on and not stress. I’ve noticed even during heat spells our vines don’t show stress like other “conventionally farmed” vineyards in our area. If you are ever out in Dry Creek Valley I would love to show you our vineyard and continue the discussion over some examples of “dry farmed wines”. My mentor for both dry farming and the magic of compost is Paul Bernier. Paul is a bit of legend in Dry Creek/Northern California for his resurrecting older declining vineyards by rejuvenating with compost, proper pruning and judicious cultivation. Cheers,
Fred Peterson 707-849-6745 (C) Sent from my iPhone
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Hi Fred, Thanks so much for your comment. It is very informative and confirms what other grape farmers have told me about dry farming and soil structure. I will pay you a visit the next time I am in Sonoma,