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The Viticultural Origins of Great Wine. The
downloadable document
Differences of Maturity within the Bunch
is drawn from a work that explores
the problem of immature flavours in ostensibly ripe
fruit. That, in my opinion, is the single greatest issue
faced in districts with a pretension to quality wine
making today. In my view this is a new problem. It has
its origin in our tendency to apply clever technology
when it yields an extra dollar. In the process we lose
sight of the quality objective. We will not solve this
problem of immature fruit by insisting on ‘Hang Time’.
What we get are some very confused and unhappy grape
growers and potential consumers who are unimpressed by
the category. Winemakers need a rationale that helps
them to identify the origins of quality in the vineyard
so that they can give better signals in the marketplace.
Here it is. If wine makers want quality, they will have
to pay for it. If grape growers serve the quality
objective there will need to be a substantial premium
paid. This document explains why. The work is entitled Grape Growing for Winemakers. If you would like an electronic copy of this work it can be purchased at a price of $50, or $60 as a CD Rom post paid. Download order form here. Email for an order form at: sales@happs.com.au or phone 61 (0) 8 97553300 or fax 61 (0) 897553846. This is a paperless work so I shouldn’t call it a ‘book’. If I do it is a slip of the tongue. The work is embodied in two Adobe Acrobat files and one MS XL file. If you are keen on making good wine this text may be the best investment that you ever make. If you have the extra cash you might like to take a bottle of our trophy winning Three Hills Merlot or our Three Hills Charles Andreas adjudged by ‘Winestate’ magazine as one of the top five Cabernets across Australia in 2005 or our Three Hills Shiraz, adjudged top in Western Australia on several occasions to assess the practice as well as the theory. If your interest is Italian you might like or our lovely Three Hills Sangiovese or the Nebbiolo instead. Then you can look at the theory and the practice at the same time. The order form is at the head of our home page at www.happs.com.au This text is ‘a work in progress’. I reserve an option to change my mind and acknowledge error. In my experience the next turn often poses a problem that was unforseen. Frequently one may have part of the answer and not the whole. Like Microsoft I intend to update the software. The published work aside……...if you have hourly temperature data for a season and want an analysis of the prospects of your favoured grape variety in your particular site by comparison with some of the classic sites around the world where that variety does well, I can help you. If you want to know the range of varieties you could plant to maximise the flavour intensity in your wine or you want to know why your chosen variety will not ripen or has little flavour intensity, I am sure that I can help with that too. Contact me at erl@happs.com.au I am open to query, suggestion and contradiction. I see this task of adapting the culture of the vine as a shared one and enjoy the interaction with like minded people. Here for your interest is the Frontispiece, the Introduction and Table of Contents of the work as it stands today.
‘Grape Growing for Winemakers’
Erland Happ
Frontispiece
In the end, science is about data and being able to read the real meaning of what you find. Keep an open mind, be prepared to think laterally, and be instructed by nature and observation. Great literature and visionary science share a characteristic: the reader recognizes that there is a sense of truth.
Science is about telling good, readable memorable stories.
Science at it’s best is for people who love to ask questions and are delighted by discoveries that overturn established ideas and prejudices. If they have to choose between authority and evidence they always go with the evidence.
Peter Doherty
Winner of a Nobel prize for medicine.
As quoted in ‘The Weekend Australian’ August 27-28th 2005
Introduction
What This Work Contains This text has been written for people interested in growing grapes to make fine wine. It is not a regurgitation of the conventional wisdom although the contents are informed by wide reading, obsessive interest and fanatical determination. It is a synthesis based on in practical experience, travel, tasting and observation driven by practical problem solving intent. Although the author’s direct grape-growing and winemaking experience relates to a particular set of climatic circumstances the ideas developed herein will have value in all environments where the grape vine is planted. The mechanics of the economy of vine production are common to all environments. The analysis relates in particular to the problems of fine wine production in climates where the ripening regime is suitable to the conservation of grape flavour. It takes little imagination to re-interpret the model to suit environments where quantity at the least possible cost is the prime objective. This is not a general text that sets out to cover all topics of interest. Others like Winkler and Galet have done that very well. A New Way of Examining the Thermal Regime of a Vine Site. The most important factor driving carbohydrate accumulation in the vine is undoubtedly temperature. The thermal regime determines the range of varieties that can be matured and the conditions under which the fruit will ripen. This text describes a reliable method for determining, before a vine is planted, the all important ripening window. This is very important. Predicting ripening date is the central achievement of the work. Using the technique developed here it is possible to determine how variations in temperature will shift this ripening window and how that will impact the viability of the enterprise. The text includes a description of thermal regime of many sites of interest to grape-growers. The reader can compare his own site to others of known performance. The analysis of the thermal regime has many original elements, it is based upon hourly rather than daily temperatures and it is has the virtue of a degree of rigour and precision impossible when one relies upon maximum and minimum temperatures. Reviewing the data from various locations, it will become obvious that the condition under which the fruit matures has a large bearing on the range and intensity of flavours developed in the grape. This has implications for varietal choice that one ignores at ones peril. All this comes about because it has been possible to measure the thermal environment more accurately. We have a new body of evidence to work with and it really helps. The Dispersion of Degree of Ripeness at Harvest Date A major influence on the quality of the vintage is the degree of dispersion in the ripeness of grapes at harvest date. One can look in vain for studies that address this phenomenon and yet it is a vital issue that must be addressed in the quest for wine of quality. The presence of immature grapes at harvest date has given rise to winemaker demand for ‘hang time’, and a consequent rise in the alcohol level of wines. Hang time does not address the viticultural issues responsible for green flavour. The phenomena of green flavour depend upon climate and cultural practices. The first third of this book is a study of the variation in ripeness that exists in Margaret River where the author’s vineyards are located. This study yields important clues as to how green flavours can persist in fruit that, paradoxically, may be showing marked evidence of over-ripeness. The incidence of green flavour depends in part on climate. In Margaret River we have a low latitude (33 degree South) west coast location in a hemisphere dominated by ocean. The landmass has little elevation and no further extension to the south. The ocean effectively buffers seasonal temperature variations and there is only a slight variation between winter and summer. There is little winter chill. Budburst tends to be straggly and consequently shoot and bunch development is staggered. The fruit ripens unevenly. This phenomenon is accentuated when the vine is overcropped and over-watered. Because ripening temperatures are moderate, all flavours including the green ones are well conserved. The plain mans guide to the production of fine wine: The identifier for the green fruit is green seeds. The tendency to have green seeds at harvest is associated with the presence of green leaves in the canopy. The possibility of bringing the crop to the same stage of desirable ripeness at harvest date depends upon plant moisture status before and after verasion and the signals that are generated in the roots that initiate leaf senescence. Ripening is best achieved as part of a process where the energies of the vine are totally focussed on the maturation of the current crop. Best results are obtained if crops are limited because there is little chance of assimilating much carbohydrate after verasion. Left to its own devices the grape vine, like most fruiting plants will overcrop. Modern viticultural practices, especially irrigation, extends the season in which the vine can assimilate carbon to ripen ever larger crops of fruit of grossly uneven maturity. Green Flavour - What It Is and What It Isn’t The astringency in green grapes that finds it's way into wine is not the same thing as acidity, tannin or methoxypyrazine. The latter is essentially tasteless although markedly aromatic and often found in conjunction with green flavour. The green taste is strongest in the relatively firm pulp found firmly attached to green seeds. As maturity is gained seed dry weight increases up to the point where the seeds develop a brown layer of relatively impermeable protective cells at which point they can be readily detached from the berry flesh. At that point the interaction between seed and pulp is finished and the green taste has disappeared. However, in unfavourable circumstances many seeds fail to mature to that point. The green taste is not due to malic acid because it is not degraded by malo lactic bacteria. It is not due to tartaric acid because it can not be eliminated by chemical de-acidification. It is not 'green tannin' because researchers have been unable to detect tannins in berry flesh, although some astringent precursors are there. There is of course plenty of tannin in skins and seeds but not the flesh. The tannins in green seeds may be more extractable than in ripe seeds but the taste of tannin is essentially different to the green flavour. Tannin binds to protein and is absorbed by saliva. Its impact on the flavour of red wine is dependent upon salivary flow. The palate impression of green flavour appears to be unaffected by salivary flow and there is no wine fining method that appears to reduce its deleterious contribution to wine flavour. Green flavour combines with acid and tannin to make wine taste harsh. If one can produce wine without green flavour the drink is more appealing with a softer impact on the mouth and the drinker is less likely to reject it. Other less potent but more palatable compounds in grape and wine flavour can be appreciated when the green flavour is below threshold. The Groundwork The early chapters are devoted to exploring the degree of difference in maturity of the fruit that can exist within a berry, within a bunch, within a vine and within a row of vines. The approach is empirical and new data is presented. It is presented in a fashion that readers will find 'unorthodox'. Where the ratio between source (the leaves) and sink (the fruit) is low, sugar distribution in the fruit is inevitably uneven. The spatial distribution of the fruit of different maturity characteristics then becomes a subject of interest because it gives us important clues as to where the strongest and weakest sources and sinks are located. One must be aware of spatial distribution of the fruit and the leaves if one is to understand how the vine as an input output engine works under different source / sink relationships. The leaves are essentially located in a different place to the fruit and the vine stores substrate and, following verasion, it flows to the fruit. The flow from stored reserves can be more substantial than from the leaves or it can be relatively insubstantial depending upon source to sink ratios and the opportunity that the vine has had to build reserves in recent months and years. The rate of influx to fruit can provide important clues as to its origin. Some of the shoots are unfavourably located in terms of their need for sunlight at a time in the day when a moisture starved vine can open it’s stomata and begin to photosynthesise. The story that emerges is that the vine is driven in part by space, time and transfer relationships. When substrate is in short supply it tends to accumulate in greater concentration in the closest sink. Even within a bunch there is no democracy. The vine is not only a factory but a bank. Some of the bank’s customers are remote and badly serviced and sometimes the bank has no reserves. We tend to run our vines less prudently than our banks. It is almost as if there is to be no tomorrow. A word about the data collected and the focus of the early chapters. The data presented in the early chapters relates to small samples of a part of a large universe. No apology is tendered for this. If one is to study how an individual vine partitions substrate to various sinks under different cultural circumstances one must look into the universe of the single vine in the particular place where the problem is most manifest ......just as you need to look at a three legged dog if you want to make observations about how that subset of dogs gets about. We are not trying to derive laws of motion that apply in all environments. It is no good doing random samples of vines or endless replications if one ends up losing the ability to discriminate between the outputs of one sort of 'engine' (or input output relationship) and another. In truth, if one is to do that, the universe that must be sampled is very large indeed. The universal truths will be correspondingly small in number and we must face the probability that the phenomena that we are interested in has disappeared entirely. Variations in the environment and vine capacity are frequently ‘catered for’ by replication and statistical analysis. However, the degree of variation that one sees between vines in the vineyard is very great and this introduces a dispersion factor that can make it very difficult to get significant results. Essentially, the argument is that replication and sample number overcomes the problems that are related to environmental variation and in this way we somehow neutralise that variation. However if we are unaware of the extra variation in vine performance that is due to factors like shoot distribution, leaf area to crop ratios, the location of fruit in relation to leaf, the mass of old wood, the weight of root, the amount of carbohydrate in storage and history of recent cropping performance, and are unable to control or account for these variables, the phenomena we are interested in may be obscured. Every vine in a row has a different cropping potential and yet they are commonly pruned to the same formula. The vine is a perennial plant that faces the task of generating sufficient carbohydrate to produce shoot leaf and crop each year. This plant deals in carbohydrate with intensity unmatched by any other. The ratio between shoot and leaf on the one hand and crop on the other depends primarily on severity of pruning. The proportion of carbohydrate that is present in annual product (leaf plus shoot plus crop) at harvest time that is actually allocated to fruit can vary between zero and 97%. It follows that the carbohydrate bank in the permanent part of the vine will vary dramatically between vines in different circumstances. The vine stores substrate against future need and the bank of substrate that it has, and the cultural circumstances that influence the bank balance are as vital to vine performance as is the productive assets, stock in hand, the liquidity, cash reserves and borrowing capacity of a business. This factor is influential in determining the variation in fruit flavour within the bunch, the vine and the row of vines at harvest date. Without an appropriate experimental design to refocus our study on the dynamics of fruit development within the vine we are unlikely to make progress in understanding the variation in fruit maturity that is manifested within and between vines. This important world of variation in performance within and between vines is a dark place. In this circumstance I believe that an approach similar to anatomical dissection is the best approach. It has served us well in our effort to understand the working of the human body. Why not the vine? The populations to be sampled will be derived from subsets of essentially similar character within the vine itself. Spatial location will be important in determining the different populations that we are dealing with. Ensuring that we are dealing with the same sort of vine in each case will demand standardisation of rooting volume, soil moisture supply and vine cultural circumstances including leaf access to sunlight, volume of permanent wood, disposition of the renewal zone, foliage support and recent cultural history. It will be essential that we match vines for their volume of stored non structural carbohydrate. All this will be easier if we culture vines in large pots that develop a plant mass that is comparable with what we see in the field. Climate and Grape Flavour One must be aware in viticultural studies that grape flavour is climate and culture dependent. There is no point in studying a vine for the incidence of a certain flavour in a location where that flavour is poorly expressed. This study is focussed on an Australian region that produced three of the five top Cabernet Sauvignon wines in a group of 400 according to the Australian wine magazine ‘Winestate’ in their review of all wines tasted in 2005. One of these is our own Three Hills Charles Andreas 2002. We produce excellent wines from a very wide range of varieties and to many an observer we might appear to lack a central tendency. The key to our versatility is the match between variety and climate. The last half of this work is devoted to the task of describing the key features of some of the locations responsible for wines of great character and other locations where the wines are more pedestrian. It will become apparent that the enabling factor is the thermal environment during the critical period when the grape matures. We are lucky in that we have a favourable ripening environment for early, mid season and late varieties. This is very unusual in the world of viticulture. The Achilles heel is that we can so easily produce lots of green flavour. Securing our future depends upon controlling that variable. The nature of the work The words ‘presumably’ and ‘possibly’ appear in the text indicating uncertainty. They should probably appear more than they do. I make no apologies for this. A good theory is better than no theory at all and speculation is the basis for intelligent inquiry. Ultimately, everything that we do is a work of the imagination. We use our mental construct of what this world is and what makes it work and that gives direction to our efforts. We look for elegant explanations of phenomena that puzzle us. It is the big picture that I seek to embrace. Space is required and sometimes questions are raised that remain unanswered. This is written by a grower/producer who, in common with others in his tribe accepts the responsibility of integrating information from a very wide spectrum of man’s endeavours. In the process, one relies on short cuts and approximations and in painting the big picture we could be short of the odd brushstroke around the edges. There is a lot of truth in the statement that “all models are wrong, but some are useful”. Model making is the process of reinterpretation based on old and new observations. The analysis attempts to integrate many factors that drive vine performance. The theorem that is developed relies upon sequential development of an argument as to how the vine behaves. It is most cogently presented in Chapter 9. The reader may need to return to this introduction and the table of contents to remind him of the purpose and general outline of the argument. The Promise The book will not provide a design for the plant spacing for your vineyard, the trellis or the end assembly structure to hold it up. What it will do is to help you to understand the factors that will enable you to determine these things for yourself. Close study of your particular environment and the prospects that you have for making wine to style and quality will be essential. When you understand the determinants of plant performance the cultural methods will follow and you will be able to select a site, the varieties to plant, the row spacing, trellis design, pruning method, tractor size, method of harvest, disease control and the determine the degree of mechanization that is practical. Without an understanding of the environmental and cultural influences on vine performance you are little better off than the person in the blindfold trying to pin the tail on the donkey.
Table of Contents
1 The context: Wine is made in the vineyard
Part 1 Studies in divergent grape maturity 2 The concepts of ‘ripe’ and ‘green’. 3 Differences of maturity within the berry 4 Differences in maturity within a single bunch 5 Differences in maturity within a single vine 6 Seed colour, a potent indicator of the state of fruit maturity 7 Differences in maturity within vine rows
Part 2 Bell Pepper Aroma and its relationship to fruit maturity 8 The role of Isobutylmethoxypyrazine
Part 3 Vine productivity and sustainability 9 The dynamics of carbon accumulation and its partitioning in grape vines 10 What is an appropriate leaf area to fruit weight ratio for a regime of early closure to target full fruit maturity? Part 4 The relationship between Temperature, Plant growth and Carbohydrate Accumulation 11 The task of predicting maturity. The concept of Carbon Gain
12 Putting the Carbon Gain index to work
Part 5 Assessing seasonal length 13 Seasonal dynamics
14 Triggers for Senescence
15 What is maturity and when is it achieved
Part 6 Developing the tools to assess key features of climate 16 Using indices derived from hourly temperatures to assess exposure to a thermal range of significance to vine and fruit behaviour.
17 A survey of the similarities and critical differences in the thermal environment that manifest between vine sites
Part 7 A Model for quality wine production 18 The economy of quality wine production. A model. Part 8 Vineyard assessment 19 Obtaining data that is critical to decision making. 20 Recording temperature by the hour Part 9 Studies in the assessment of viticultural climates 21 Case Studies
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© Copyright 2000 Happs Pty. Ltd. Western Australia. All rights reserved.
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