New World Winemaker Blog » Bruce Zoecklein

Reductive strength

Bruce Zoecklein — Thu, 15 Dec 2011 23:00:54 +0000

“The mystery of why some wines live and some wines die young should haunt every serious New World winemaker” – Randall Grahm Bonny Doon Vineyards

As discussed in previous postings, longevity may be considered within the pantheon of wine quality. The reductive strength of a wine is a measure of oxygen uptake and the ability to handle that uptake, that is improve with age. In red wines this is influenced principally by phenols and impacted by several winemaking protocols.

In a recent study (Kassas and Kennedy 2011) wines commanding the highest market value had several attributes in common including the highest concentrations of total tannins, the highest concentration of skin tannins and tannin-anthocyanin bound pigment polymers.

In grapes and wines, anthocyanin pigments can be either free monomers, that is, unbound, or associated with other compounds including phenols such as tannins to form polymers.

Tannin polymerization in fruit and wine continues until an anthocyanin molecule binds the terminal ends of the tannin chain forming ‘bookends’, thus stopping the polymerization. As such, the ratio of anthocyanins to tannins is important. This ratio impacts the extent of polymerization and, therefore, astringency.

Large tannin-tannin and tannin-anthocyanin polymers provide a relatively large number of binding sites to interact with proteins, as well as salivary proteins. As such, wines with an abundance of large polymers tend to lack softness and often possess a dry mouth sensation.

Conversely, smaller polymers have fewer protein binding sites and produce less astringency while providing a softer mouthfeel and often more palate depth. These smaller polymers are associated with enhanced reductive strength and wine aging potential.

Some phenols (diphenols) have the ability to react with oxygen, bind with another phenol, and recreate the original structure-thus allowing it to react over and over again. This helps explain the rather counter intuitive feature of exposing a young wine to oxygen and making that wine more resistant to oxidation. Young red wines can consume oxygen, actually increasing reductive strength.

Randall Grahm of Bonny Doon Vineyards in California considers reductive strength to be analogous to a wine’s chi or, as the Chinese say, life force. When a wine is young, it can share its chi with the world; when old, it must guard it so the wine does not diminish too quickly. Young wines have a capacity to adsorb oxygen and that can actually increase its resistance to later oxidation. Irrespective of chi, we believe that reductive strength is related to the phenolic composition of a wine and, therefore, to longevity.

“Experience is the name everyone give to the their mistakes” - Oscar Wilde

Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.

His Enology Notes are available at www.vtwines.info.

This NewWorldWinemakerBlog.com post was written by Bruce Zoecklein

Science-based versus Empirical Knowledge

Bruce Zoecklein — Fri, 11 Nov 2011 10:40:01 +0000

“Experience enables you to recognize a mistake when you make it again.”
– Bob Steinhauer-former Director of Vineyard Operations, Beringer Vineyards, CA

The kaleidoscope of viticultural and enological choices winegrowers must make reminds us of the complexity of our industry and how rapidly our philosophy and practices have changed as new knowledge is acquired.

To move forward, not laterally, from one vintage to the next, we need to keep Ray Koch’s famous remark in mind, perhaps with a slight modification: “You cannot manage (understand) if you cannot measure.” Our challenges, therefore, in crafting fine wines, include the understanding of the following:

Environmental factors, vineyard management and fruit chemistry

Fruit chemistry and wine chemistry

Wine chemistry and sensory properties

To some, this mechanistic approach may appear to be contra natura, against their philosophical nature and against artistic winemaking. However, a resolution of the above relationships goes to a core belief – that luck is the residue of design. As John Fowles stated, “For what good science tries to eliminate, good art seeks to provoke – mystery, which is lethal to the one, and vital to the other.” However, art and science are supplementary. That understanding will allow us to follow an important mantra: keep things as simple as possible, but not simpler.

In order to optimally use both science and art, we must understand the difference between empirical or observational knowledge, and science-based knowledge. We must know the limits and merits of each. Empirical knowledge is sometimes faulty, because what may apply to one circumstance may not to another. The question is one of relativism. What information is universal, and what information is specific to time, place and circumstance?

As an industry, the distinction between science-based and empirical knowledge is sometimes blurred. What works at one vineyard site certainly may not work at another. We know this intellectually, but sometimes fail to keep this in mind. Another problem with relying solely on empirical observations is that, if two outcomes are similar, we have a tendency to assume they must have a similar cause. This may or may not be correct.

One of the steps that can aid in understanding the relative merits empirical and science-based information is to develop a HACCP plan. HACCP or hazard analysis critical control points, is a system for assuring product quality control from beginning to end, through the identification and monitoring of the critical control points (CCPs) during processing.

Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.

His Enology Notes are available at www.vtwines.info.

This NewWorldWinemakerBlog.com post was written by Bruce Zoecklein

Organic Is Better, Right?

Bruce Zoecklein — Fri, 21 Oct 2011 14:09:08 +0000

There is no word for winemaker in French, Spanish, Italian or German, pointing to the ingrained belief that wine is made by nature, not by man. The conviction has been held for centuries in the Old World-that wine is, at its core, the reflection of a place. While there is no single-word translation of terroir into English, the French will often use this one word to explain why a wine tastes the way it does, as a result of its place. This is a basis for a present-day concern: Is industrialization muting the effect of place?

The consumer is left to answer the questions: Did this fine wine I am enjoying come from a great vineyard in a top appellation, from a talented winemaker using some dazzling new technique, and/or from a slew of agricultural and/or processing chemicals?

The sense of place is a concern as the world and its products become industrialized, sparking renewed interest in chemicals used in our foods, including wines.

A capstone event occurred in 1990 in theUSwith the Alar episode. Alar, a growth-regulating chemical widely used in orchards at the time, was later listed as a carcinogen. The consumer’s negative reaction was a potent catalyst for the organic food movement. The question of whether agricultural chemicals are good or bad was catapulted to the forefront inAmerica, and remains.

Currently, there are at least two theories as to why the lack of chemicals may be a good thing (beyond the purely psychological), both relating to the production of so-called secondary plant metabolites, that is aroma, flavor and phenols.

Plants produce these for several reasons, including defending off pests and disease. Some believe that plants defended by man-made chemicals do not need to work as hard to make their own natural pesticides, such as phenolic compounds. They do not need to expel their limited energy producing as many secondary metabolites.

Another theory suggests that soils that have been significantly altered with chemicals are simpler. While they may contain the required NPK etc., these soils may not contain all of the raw ingredient precursors that plants need to produce the vast array of secondary metabolites in optimum quantities or proportions.

There is some scientific evidence for both of these theories. For the wine industry, however, the question comes down to wine quality. To date, there have been few studies that suggest that the lack of approved chemicals consistently produce better wines.

Not using chemicals, particularly agricultural chemicals, sounds great and is certainly consistent with our general notion of sustainability. Unfortunately, there remains a void of scientific data suggesting that not using chemicals improves wine quality. Unfortunately, at this time the choices may be like the old joke:

I have theory that it’s impossible to prove anything – but I cannot prove it.

Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.

His Enology Notes are available at www.vtwines.info.

This NewWorldWinemakerBlog.com post was written by Bruce Zoecklein

What constitutes a high quality wine? Part 2

Bruce Zoecklein — Fri, 23 Sep 2011 08:44:55 +0000

What are the characteristics of a great wine? The following are a few features of a great wine adapted, in part, from Robert Parker (2008). Which of these do you agree with? What would you add or delete?

The ability to please both the palate and the intellect. Great wines should offer satisfaction on a hedonistic level, and challenge and satiate the intellect. There are many delicious wines that appeal to the senses, but lack profundity. The ability to satisfy the intellect is subjective, but experts often prefer wines with multiple dimensions, both aromatic and flavor.

The ability to hold the taster’s interest. Profound wines could never be called monochromatic or simple. They hold interest, not only providing an initial tantalizing tease, but possessing a magnetic attraction due to their aromatic intensity and nuance-filled layers of flavors.

Ability of a wine to offer intense aromas and flavors without heaviness. In some parts of the New World it has been easy to produce wines that are oversized, bold, big, rich, but heavy. It has been said that Europe’s finest wines have intense flavors without heaviness.

The ability of a wine to taste better with each sip. Most of the finest wines are better with the last sip than the first, revealing more nuances and more complex aromas and flavors as the wine unfolded.

The ability of a wine to improve with age. Many consider longevity an indisputable characteristic of great wines. Some suggest their wines will age when they mean their wines will survive. They can endure in the bottle, but are much more enjoyable in their exuberant youthfulness. If you open a bottle and drink a glass and replace the closure, a wine with longevity should stay fresh for the better part of a week. Most New World wines are generally dead the next day, while many of the finer Old World wines are not. Why? To varying degrees, wines consume oxygen. Likely, longevity has to do with reductive strength or resistance to oxidation. Reductive strength is linked to the phenol content, lees involvement and possibly the nebulous concept of minerality (See Enology Notes #160). Minerality, or capacitance is thought to give the primary flavor a sense of soulful depth or relief, providing a shadow or added dimensionality. This could relate to a number of viticultural parameters and practices, including soil and the biological nature of the soil. This has been described as petrichor, the smell that a new rain liberates from rock. Others describe this as an almost electrical-type buzz provided by the wines finish. Some believe that this resistance to oxidative change is a sort of Rorschach test.

Whatever definitions of wine quality we adopt, we need to continue to evaluate our products and assure ourselves that our knowledge is increasing from one season to the next.

Art is not the cultivated taste; it is the cultivation of taste – Nikki Giovanni

Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.

His Enology Notes are available at www.vtwines.info.

This NewWorldWinemakerBlog.com post was written by Bruce Zoecklein

What constitutes a high quality wine? Part 1

Bruce Zoecklein — Thu, 15 Sep 2011 23:00:42 +0000

What is a great wine? Is it enough to simply provide naïve pleasure, or must a wine make an eloquent statement? Wine is art and as Jean Anouilh stated-the object of art is to give life a shape. To many in the wine world, real wines convey a sense of place, a genuine originality. The relativity of experience impacts one’s evaluation. Greatness in wine is much like a profound expression of art or music, depends upon personal experience and is subjective. Even though there is no singularity, definition greatness in art, music, or wine, though difficult to define precisely, enjoys a broad consensus.

Sensory evaluation is subjective. Like many of the finest things in life, however, there is considerable agreement as to what represents high quality. As Robert Parker states “No one should feel forced to feign fondness for a work of Picasso or Beethoven, much less a bottle of 1961 Latour.” Exceptional wines emerge from a philosophy which often includes the following:

Proper varieties planted in the correct climate; expression of the vineyard’s terroir; purity and characteristics of the grape variety or blend to be faithfully represented; and minimalistic winemaking.

Most consider that the world’s finest wines emanate from fruit grown in well-placed vineyards with microclimates favorable to the specific varieties. There is no such thing as the best grape or best clone, simply one well-suited to its growing environment. In the US, consumer’s palates are not tuned to terroir. We want jammy fruit, lasting intensity. Such wines may fool our senses in the same way that our primary physiology responds to the fat in a McDonald’s hamburger. Many of these are “feel good” products, the vinous equivalent of comfort food (Randell Grahm of Bonny Doon Vineyards). Is this bad? No, not as long as they are well made. They can obscure our link to the vineyard, if a host of addition products are employed. Such obscurity may limit the pace of industry development. Such wines appeal to a certain attitudinally-challenged denominator and may be a key link to our biological predisposition to favor fruit over complexity.

Some equate quality with quantity. This is true, regardless of whether we are talking about degree of ripeness, oakiness, or tannins. Are we making wines that are easy to like, but sometimes difficult to love? Perhaps we need to concentrate on means of adding some texture without deforming the ethereal essential character of a wine. We should not have the illusion that we can or should control everything. Minimalistic winemaking philosophy, when possible, allows for an intrinsic character, so that what is placed in the bottle represents as natural an expression of the vineyard, variety, and vintage as possible. This requires restraint in the use of adjuvants, cold treatments, and filtrations.

The greatest obstacle to discovering the truth is being convinced that you already know it.

Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.

His Enology Notes are available at www.vtwines.info.

This NewWorldWinemakerBlog.com post was written by Bruce Zoecklein