Science of Sustainable Viticulture

John Williams

Frog's Leap Winery

People become interested in the sustainable agricultural movement for a variety of reasons. Many share a concern for the environment and envision greater stewardship of the land. Others may be attracted to issues of farm worker safety or perhaps community concerns over pesticide use. Some may be attracted to the lower costs and higher productivity of sustainable farming. Then there is the attraction of positive public relations that come with ecologically sound practices. Frog’s Leap Winery has been farming sustainably for over fifteen years now and we dry-farm over 200 acres of certified organic vineyards. Through our grower program, we have influenced the organic certification of a dozen different vineyards covering over eight hundred acres. I can say that we have benefited in a very positive way from all the reasons for farming sustainably mentioned above and more. It remains, however, that the best reason to farm sustainably is the improvement of wine quality.

Simply put: the principles of organic farming and sustainable practices are the single most important tools you can employ to improve wine quality. Most, if not all, challenges you face in winemaking can be positively influenced in a significant manner by a closer relationship with the natural eco-systems responsible for growing your grapes.

Now, I am fully aware that I just used the word none of us ever thought we would ever hear at an ASEV convention and I know that many are more comfortable with the word sustainable than the word organic. In truth, however, the principles of organic farming are the fundamental and inseparable basis for sustainable agricultural systems. It is the deep respect and care for the miraculously complex soil organism that cannot be separated or ignored in this discussion. A healthy soil enriched by the organic matter of compost and cover crops and left alive by avoiding toxic herbicides, fumigants, nemadocides, and the like, is the building block of great wine.

Here is the major point: A healthy soil produces a healthy vine; a healthy vine produces healthy fruit; healthy fruit produces healthy wines: deep in color, deep in flavor and deep in their natural character.

Pick nearly any problem in winemaking today and you will find with a minimum of research a deep connection to farming practice.

Having a problem with stuck fermentations? You are not the only one. Linda Bisson and Christian Butske’s paper on “Stuck and Sluggish Fermentations,” (AJEV Vol. 51) lists sixty-four reference papers on this subject. Their conclusions, among other reasons: “Poor yeast nutrition;” “The harvesting of grapes later and at a higher sugar content” to produce more flavor; Toxic substances in the must and low amounts of assimilable nitrogen. It may not be immediately apparent to everyone, but to the vintner using organically grown grapes, you would give a knowing nod. We used to have those problems until we built natural blanced soil fertility, stopped using sterol inbibitors, stopped spraying with dimethoate and started getting flavors at 23 and a half Brix instead of 28 and a half Brix.

Got sulfides? Park, Bolton and Nobles’ most recent paper on the subject (AJEV 51#2) points at the causes. Three of the five most frequently associated causes of hydrogen sulfide production during fermentations are related to nutritional stress and other adverse must conditions. These conditions can be directly related to nutrition status of the grapevines themselves. As humans, we know that if you only eat beans you’re going to stink up the place. The winemaker’s solution? Add nutrients to the must. The organic growing solution? Develop the incredibly complex microbial world in your soil that degrades the organic matter in a balanced and measured way promoting low vigor and high nutritive value. Think you can get enough nitrogen in your must by adding more N fertilizer to your vineyard? Spade, Nagel and Edwards (AJEV Vol. 46) conclude that yes, you can, and suggest a minimum rate of 56 kg N/ha/year. They do point out though that this rate might have some adverse effects since it would surely lead to excessive vine growth, delayed fruit maturation, increased juice and wine pH, herbaceousness, poor color development and a lack of flavor. Maybe if you add the fertilizer to the irrigation water . . . there’s a good idea . . . fertigating grapevines instead of promoting balanced soil nutrition is like giving a coke and a candy bar to your child for dinner. The immediate result might be impressive, but the eventual output is not.

There have been a minimum of ten papers in the AJEV in the last ten years on the effect of nitrogen fertilization in grapevines. Most of the papers deal with the downsize – excessive vigor, poor color development, increased pH, problems with rot, high arginine correlated with ethyl carbonate production. But some papers dealt with the upside – increased yield – great, lots of bad fruit. Jackson and Lombard in their review “Environmental and Management Practices Affecting Grape Composition and Wine Quality (AJEV 44#4) modestly conclude that, “while the evidence does not allow us to pinpoint the exact nature of the response to nitrogen fertilizer, it is such that growers can be cautioned against its excessive use. They go on to sum up the effects of soil on quality in the same paper in four ways: (1) the effect on moisture availability to the plant due to its moisture-retaining capacity; (2) effect of nutrient availability; (3) effect on microclimate due to heat-retaining and light reflecting capacity and (4) the effect on root growth due to penetrability. Any organic grower would tell you that all four of these effects can be positively improved using sustainable farming techniques.

Truthfully, we could go on and that’s even before we get into racking by the moon and bottling using tidal charts. Pretty soon, I’ll be trying to convince you that organic farming will cure hair loss and improve your love life.

So far, we’ve only been talking about making better wine. Now, let’s get to the really good part – increasing wine quality.

Now, I have to admit that when assigned to do this talk, I had to look up the definitions of a couple of words. The first word was “Science” – since this session is the Science of Sustainable Viticulture and since it’s been a few years since I was behind the test tubes in Professor Ough’s laboratory, my Webster’s definition of science heartened me. Mr. Webster defines Science as “knowledge especially that gained through experience.”

The second definition I had to look up was Quality. Here’s what Websters has to say about that: Quality: (1) the essential character or nature of (2) an inherent or distinguishing attribute.

Now, we’re getting somewhere, for, as important as it is to promote making wine better, the exciting part of this talk is about bringing out the inherent qualities of a wine and the place it is grown. If you believe, as I do, that the essence of winemaking, the Holy Grail as it were, is to make wines that deeply reflect the soil and climate from which they emanate, it seems self-evident that you would want every molecule, every enzyme, every ester, every flavonoid, every protein, every essence, to be derived from the soil in which the grapevine is grown. And if you achieve that, the product of that vine will imbue the essential character of its place. Real quality wine.

Without soil-based flavors, we, as winemakers, are stuck with trying to manufacture those flavors on our own, Thus, ridiculously excessive overripe grapes, spinning cones, esterifying yeasts, reverse osmosis, super malo-lactic cultures, micro-oxygenization, mega-purple, flying winemakers and 200% new oak*

Just because some of our hapless wine critics think that this is what wine is all about, I, for one, am not sure people who truly love wine are buying this, and these days I mean that literally. I personally think that these wines taste all the same, that they deliver little pleasure and that they develop little, if any, nuance in the bottle.

If you want real pleasure in a wine, if you believe that a wine has a soul, if you believe in the natural quality of wine and its dependence on place, you will be left with the inescapable conclusion, as have I, that we need to grow our vines deeply in their soil. We need to retain adequate amounts of organic matter back to our vineyards. We need to, at all costs, promote the vastly complex biological life in our soil, and that means the complete banishment of toxic herbicides and, yes, I include glyphosates. We must promote soil structure and moisture retention capacity to significantly reduce, or, better yet, eliminate irrigation. We must cultivate our vines to promote deep root growth. We must banish chemical fertilizers and other growth stimulants. We must return natural soil fertility to complete balance for, in doing so, we will eliminate excessive vigor and all of its related problems. We must promote as much bio-diversity in our farming system as is possible as this will be our best defense from a host of problems from gopher damage to Pierce’s Disease. We must support our farm workers through liveable wages, healthy work environments, adequate healthcare and respect for their contribution. We must be conservative in our use of resources in every way. And, we must be respectful of our larger community, to our nature and to our God. Then, at the end of that day, we must raise our glass and toast ourselves – for those who have the privilege of growing grapes and making wine sustainably are the truly blessed.