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New World Wine Maker Blog - winemaking

Acid Trip Mea Culpa

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The 2013 harvest is coming up in in a few weeks. Every year I start planning the next vintage as soon as the previous one is done, but as the harvest draws near the thought process gets particularly fraught. About now I make a dispassionate, unstinting assessment of what worked and what didn’t, and what I’m going to do differently this year.

Back in April I released out 2010 Estate Pinot Noir. Let me say at the outset — I LOVE this wine. It is complex, fruity, mineral, has great concentration,and is generally representative of our vineyard site and my winemaking goals. I believe that this wine has the potential for at least 20 years of positive development.

And I also believe it could have been better.

I’m absolutely certain that it is my fault that it is not.

This Pinot exhibits two characteristics that are the direct result of things I did or didn’t do in the winery, things that I made a conscious choice about. 1) The wine exhibits ethyl acetate — a very fruity, estery, slightly chemical solvent smell. We used to say “it smells like airplane dope” because model dope is mostly ethyl acetate. But almost nobody builds those kind of planes any more. Anyway, the wine has a pronounced whiff of ethyl acetate. And 2) the wine is VERY acidic.

Both of these things are there because of choices I made in the winery. The ethyl acetate is there because I chose to not inoculate the Pinot Noir with a commercial strain of Saccharomyces yeast. For years I have been allowing the Pinot fermentations to take off on indigenous yeast — the yeast present on the grapes and winery equipment. One of these indigenous yeast is Kloeckera — a fairly robust fermenter that produces ethyl acetate as a by-product of fermentation.

In past vintages, I have allowed the Kloeckera to conduct part of the ferment, and then inoculated with Saccharomyces both to ensure that all the sugar is used up in the ferment (Saccharomyces is more alcohol-tolerant than Kloeckera, and so will complete the fermentation of high-sugar musts that would challenge most Kloeckera strains) but more importantly: for the Saccharomyces to take up and metabolize the ethyl acetate produced by the indigenous Kloeckera.

The 2010 Pinot fruit came in at lower than average sugar — 23.9° Brix. The ferments blasted through, such that Kloeckera pretty much completed the fermentation before the Saccharomyces could take over—much less dominate—the yeast population in the tanks. The ethyl acetate was there, and there it stayed. I actually like it a little, but it doesn’t need to be there. And a part of me still associates ethyl acetate with some nasty-ass “natural” wines I tried back in the 70s and 80s. Lesson for 2013: Don’t allow the strain of Kloeckera I have floating around the winery to dominate the ferments.

But I have a bigger issue with the high acid level in this wine. I have posted before about the 2010 vintage. The vintage presented a number of winemaking challenges arising from the relative coolness of the season. The juices had normal to slightly above normal levels of acidity, more malic relative to tartaric than usual, unusually LOW levels of potassium, and relatively high pH. Trial tartaric adds did not drop the pH significantly, and so I made little or no acid addition to the various lots.

What surprised me with the 2010 Pinot was that very little of the total acidity fell out of solution as tartrates. The resulting wine was tart post-malolactic. And this is where I did something I have sometimes chastised consulting clients for: I let a philosophy trump practicality.

The philosophy was “hey let’s be more natural and true to the site and the vintage, and keep the number of additions to a minimum.” The practicality is that this wine probably would have tasted better if I had added a little carbonate (to precipitate some of the acidity). I never even did the trial. But here’s the reality — with all due respect to Alice Feiring, Raj Parr, Jon Bonné, Dan Berger and all the other writers and sommeliers (and winemakers) touting a lower alcohol, higher acid style of wine:

High acid wines are just not as enjoyable to drink as wines with moderate, balanced acidity.

I’m no fan of what I call “cocktail” wines: the high alcohol, high pH, high extract, high oak, high point score grape-based beverages that have dominated the attention of the wine world for the last decade. I am all for moderate alcohols, by which I mean under 15%—preferably closer to 14%. I have tasted some varieties of North Coast wines that are balanced at even lower alcohol. But I’ve been doing this long enough to remember when this pendulum swung before. I recall that the North Coast produced some really insipid wines in the late 70s and early 80s when last the industry felt it necessary to produce a more “European” style. I don’t want to go back there.

So here’s the lesson learned: Spend some time and money doing acid add forecasting. Don’t hesitate to go to the bag, for tartaric or for carbonate, as needed to get a “balanced” wine — by my definition of balance. Don’t let some dubious “philosophy” dictate what I do in the winery.

 

John Kelly is the owner and winemaker of Westwood Wines, Sonoma California. This blog was originally published on his blog: “notes from the winemaker” on the 19 August 2013

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A List of Details

 

I’ve often said “There are only two processes to winemaking. Flavours are created in the vineyard and extracted in the winery. The rest is only details”.

Every time someone speaks of a great new winemaking process such as cold maceration or délestage, it’s time to ask yourself “Is this consistent with the style of wine I want to make?” Will this improve my process or handicap it? Will this create a greater risk of something going wrong? Break the process down into its individual elements and consider the effect of each element on flavour development. For example, a prefermentation cold soak selectively extracts water soluble compounds whereas extended post fermentation contact selectively extracts alcohol soluble components. The influence of aeration is affected by the stage at which it occurs. An early aeration can oxidize tannins and diminish their solubility whereas later stage aeration will diminish tannin astringency but may contribute to bitterness.

In some ways there is less flexibility during white grape extraction, so winemaking is more affected by grape flavours. If you wish to suppress flavour extraction, for example when working with over ripe grapes whose cellular structure has begun to break down, then you may resort to a whole cluster press. This occurs when making the typical big alcoholic Chardonnays that are left to hang until the berry begins to become flaccid. If the typical destemming were used, then tannin extraction would be a problem. This style of winemaking typically occurs at an elevated pH and runs the risk of developing bitterness in the presence of higher tannin extraction. Whole cluster pressing is also used when making a sparkling cuvée. The first, gentle press will have very little tannin extraction and is considered to be the premium part of the cuvée. Each subsequent pressing will have higher tannin content and should be kept separate, and perhaps treated with isinglass or gelatin to precipitate the tannins.

 When working with aromatic grape varieties the strategy is completely different. In this case the objective is usually to maximize flavour extraction. There is a hierarchy of aggressiveness that can be used. The most common technique is to simply run the berries through a destemmer and then press. The aggressiveness of pressing and the thoroughness of crushed berries affect the level of extraction. Flavour extraction is also affected by berry pH and sulfite. A more aggressive extraction can be carried out by using cold maceration prior to pressing. A convenient timing for cold maceration is to destem and crush in the afternoon and press the next morning. Again, the amount of air contact and presence of sulfite affect flavour. If tannin extraction is expected to be a problem, then a small amount of gelatin or isinglass can be dispensed into the crushed berries after destemming. An even more aggressive extraction of white berries can be made by adding pectinase during maceration. In this case it is highly recommended that gelatine or isinglass be added during the maceration. Tannins will tie up pectinase and inactivate it.

With aromatic varieties much of the aroma is often present as non volatile terpenes. These compounds can only be detected by the nose after they are converted to the volatile form. Many yeast contain a beta glucosidase that can carry out this reaction, but if you’re wanting more aroma, you can buy the pure enzyme preparation from suppliers.

The way in which you extract berries can also affect the stability of the resultant wine and its eventual sulfite requirement. Pre fermentation oxygen contact causes browning, especially noticeable in white wines. This results in wine that has a lower bound sulfite and is more heat stable without treatment. The down side is that you may also diminish varietal character if your oxidation is too aggressive.

I haven’t touched on the ways in which a vineyard can be manipulated to develop flavours nor have I suggested ways of blending different varieties. I’ve heard it said that if an identical batch of grapes were split among a dozen winemakers, they would still produce a dozen different wines. Even winemakers with the same training eventually develop a preferred pattern that results in recognizable differences. The potential process variations are essentially infinite. Every time the winemaker touches the process he leaves his fingerprint.

 Gary Strachan is an expert consultant and planner for the grape and wine industry. He can be reached at gestrachan@alum.mit.edu

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The Winemaker as Artist

I have often written that there are only two processes in winemaking:    Flavours are created in the vineyard and extracted during winemaking.    I should probably add a third.   Flavours are modified by fining.    Apart from the removal of gas bubbles from molten glass, no one but a wine or beer maker seems to use the term fining.    If I were a visual artist, I would compare fining to the touches given to a painting to emphasize or suppress an image; the strength of highlights or depth of shadows.   

A winemaker is a sensory artist.    His pigment is a drawn from the vineyard and his brush a stainless steel tank or oak barrel.   There are no two identical wines.    Each wine is unique if you search out the details.    The winemaker’s mental image shapes the sensory properties, and lab analyses give reassurance of the pathway to create the wine conceived in the mind.  

The fundamental structure of a wine is determined by the chosen variety, the climate and soil in which it is grown, vineyard management, and stage of maturity at which it is harvested.   The winemaker must then decide on the strategy to be used to extract flavours.    There are so many ways to extract a grape that this stage alone is sufficient to account for the variation between wines of the same variety from different wineries.     This is not to minimize the influence of other factors, but winemakers often develop an extraction style using favoured techniques.    Those who become familiar with a particular winemaker’s style can often recognize wines from that winery, even though they may be from a different grape variety.    No other memory is as persistent as that of smell.

In a perfect world, there would be little else required of the winemaker except to extract, ferment, stabilize the wine, and clarify it for bottling.    But nothing is that perfect.    Sometimes a wine doesn’t settle easily or there may be an off note on the palate.    Now is the time for a fining agent.

The most fundamental fining agents are those which are insoluble, but have a property which enables them to remove an undesired component from a wine.   The best known of these is bentonite clay which is used to remove undesired protein from white wines.    Soluble protein can return to undermine the winemaker’s vision of a near perfect white wine by creating a haze months or years after it has been bottled.    A grape-derived alternative to bentonite is tannin.    Most red wines have enough tannin that they require no bentonite.   Tannin and bentonite each have an opposite molecular charge to protein, thus soluble protein will be neutralized by tannin or bentonite and will precipitate.   Higher levels of tannin remain in the wine and contribute to mouth feel and astringency, but excess bentonite can be a serious problem because it can create a non filterable haze.

During the past few years we have learned a great deal about many traditional practices of winemaking  and have put a new spin on them.    Winemakers have used a process called bâttonage for centuries but in recent years an objective examination of the process revealed unrecognized benefits associated with the practice.   In addition to imparting savoury sensory notes, the practice increases body and imparts antioxidant properties to the wine.    It consists of allowing the wine to remain in contact with the lees for an extended time.   The lees are regularly stirred in order to resuspend them in the wine and assist the dead yeast cells to break down and release their contents.   In recent years, wine ingredient suppliers have recognized the risk of developing off flavours that accompanies bâttonage and have made autolyzed yeast available as a wine treatment.   It’s become a simpler, more consistent part of the winemaker’s palette (not to be confused with palate, pallet, or pellet). 

The use of a fining agent that also imparts sensory properties moves the concept of fining agent into the realm of wine ingredient.   There are a number of commonly used winemaking practices that are gradually moving through this transition.   A common example is the use of oak barrel alternatives such as toasted oak chips or oak extracts.    This controversial alternative treatment can develop the nose, flavour, and palate of wine at much lower cost than the extraction of oak components from an expensive barrel.   When the oak alternatives are coupled with the exact oxidation of a micro-oxidation system, the process becomes not only less expensive but more exactly controlled for flavour development than the barrel alternative.    Barrel to barrel variation is eliminated, but the process can go terribly wrong in inexperienced hands if the wine is inadvertently over oxidized.   The highlights and shadows can be masked by the bitter and nutty notes of oxidation.

Modern winemaking is a highly competitive business with quality moving steadily upward.   The most important role of the winemaker is to provide the vision of the best he can extract from the vineyard and to know that if the best is not good enough for the market, then how he must upgrade it.

Gary Strachan is an expert consultant and planner for the grape and wine industry since 1977

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Wine Phenols – White Varietal Processing Considerations

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White varietal processing is largely aimed at minimizing phenolic extraction (except with the use of oak addtivies). This starts with harvesting. Machine harvesting grapes leads to greater berry breakage and increased skin/seed/stem contact compared to hand picking. Hand-picked grapes will usually undergo whole cluster pressing because maintaining the berry structure for as long as possible will help keep soluble solids to a minimum. With machine harvested fruit, pressing grapes as soon as possible will help limit phenolic extraction by decreasing skin contact.

Short-term skin contact (up to 12 hours) is particularly common with aromatic varietals such as Gewurztraminer, Albarino, and Sauvignon Blanc; this is typically desired for increased extraction of aromatic compounds and aromatic precursors rather than phenols. During these processes, phenolic extraction is kept to a minimum through the use of carbon dioxide and sulfur dioxide (limit oxidation) and during solids separation procedures.

Separation of free-run and press-fraction juice is commonly practiced in wineries (this will be discussed in more depth in a separate post). In regards to phenolics, press-fraction juice will have higher concentrations of flavonoid phenols due to higher soluble solids and increased contact with stems and seeds, and higher concentrations of hydrolyzable tannins due to oxidation.

Additives during pressing and solids separation are commonly used to decrease phenolic extraction. Sulfur dioxide is commonly added to machine harvested grapes pre-pressing to limit oxidation. Various commercially-produced enzymes, primarily pectinase, aid with the removal of soluble solids during solids separation activities (enzymes and solids separation will be discussed in depth in a following post). Bentonite, PVPP, and gelatine are all applicable for fining pre-fermentation and post-fermentation. Bentonite does not directly react with phenols but does help precipitate protein-phenol complexes; it is often used in conjunction with enzymes during cold settling to decrease soluble solids and create more compact lees. PVPP (polyvinylpolypyrolidone) is used specifically for removal of flavonoid phenols, while gelatine is more effective for removal of nonflavonoids. All fining agents can have a negative effect on aromatic compounds, so they are often considered a double-edged sword and application must be done carefully.

Hyperoxidation can also be used to remove phenols in white grape juice. This technique is primarily used on press-fraction juice and requires minimal sulfite levels. The juice is saturated with oxygen, leading to oxidation and sedimentation of phenolic compounds. Just like using fining agents, this technique will often lead to significant losses of aromatic compounds.

Oak may also be used during fermentation and maturation with various white varietals, most notably Chardonnay (oak and oak additives will be discussed in a following post).

Phenolic extraction with white varietals is desired by an increasing number of winemakers in order to produce desired wine styles with more body and mouthfeel.

The increasing popularity of ‘Orange wine’ in the modern market is just one example (no, this is nothing new; on-skins fermented whites have been produced for thousands of years). Some winemakers are beginning to think differently, using on-skin ferments and high-solids ferments to produce blending components. These wines often lack desired aromatics and flavours but have structure; integrated into blends, they produce wines of character that have the best of both worlds.

See previous posts on Wine Phenols: Flavonoids & Nonflavonoids

 

Mike Horton, the surfer with a passion for winemaking. The original blog Wine Phenols : Nonflavonoids and Flavonoids was originally posted on his blog: the drifting winemaker.

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Bacteria in winemaking – it’s all about timing

Cheese

“The early bird gets the worm, but the second mouse gets the cheese.”
Willie Nelson

Being early is not always a guarantee of success, especially if you’re a mouse. Evidently, timing is critical. An example of this is gossiping about a colleague when he or she walks in (I never do this) or adding lysozyme to your must before co-inoculating with yeast and bacteria. As far as the latter example of bad timing is concerned, I know of a winemaker that did this. Suffice it to say, no MLF took place.

Timing is usually critically important in any winery, especially when it comes to the tiny microbes in your fermenting must and wine. The presence or absence of yeast and bacteria at certain stages of the winemaking process will ultimately determine the quality of your wine. For instance, a beer brewer phoned me a while ago and complained about bacterial spoilage of his artisan beers by lactic acid bacteria. I recommended Delvozyme® (a lysozyme preparation that Anchor sells locally) and have not heard from him since. No news is good news, right?

Another case comes to mind. A winemaker told me that he’s been involved in a long-standing feud with ubiquitous LAB that perennially invade his barrels of premium Chardonnay. The winemaker has since made a compromise, as a certain percentage of barrels are allowed to be annexed by the marauding LAB and the remainder of the barrels are treated with lysozyme. All the wine is eventually blended and the combination of wine with diacetyl notes versus more fruit driven wine has proven to be quite enchanting.

As a parting shot, I read about an Australian winemaker that was told by a consultant that he could use less sulphur in his wine if he used lysozyme during stabilisation. The end result; an oxidised, microbiologically stable wine and a well-timed kick to the consultant’s backside!

Bernard Mocke is a technical consultant for Oenobrands

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If Only the Grapes Were the Whole Story

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Wine has been described as the perfect beverage because the grapes contain all the ingredients necessary to create their transformation. Put grapes in a vat, and over time the yeasts coating the skins set alchemy in motion, converting the sugar in the juice into alcohol.

It was just this sort of unbidden fermentation that inspired humans so long ago to spend the next few millenniums improving their methods of winemaking.

A few wines are still made in this way, or at least in approximation, with no other ingredients except the possible addition of sulfur dioxide, which has been used for eons as a stabilizer and preservative. Yet it’s no secret that many wines (most, in fact) include a lot more than grapes, yeast and sulfur. The list in some cases can be staggering.

Forget about the often poisonous chemicals used in the vineyards, which can leave residue on the grapes. In the winery alone, before fermentation even begins, enzymes may be added to speed up the removal of solid particles from the juice, to amplify desirable aromas while eliminating disagreeable ones, to intensify the color of red wines and to clarify the color of whites.

It doesn’t stop there. Other additives can be used to enhance a wine’s texture, to add or subtract tannins or simply to adjust quality. Winemakers can select specific yeasts and special nutrients to keep those yeasts working. They can add oak extracts for flavor and further tannin adjustment, and compounds derived from grape juice to fix color, texture and body. They can add sugar to lengthen the fermentation, increasing the alcohol content; add acid if it’s lacking; add water if the alcohol level is too high. Or they can send the wine through a reverse-osmosis machine or other heavy equipment to diminish the alcohol and eliminate other undesirable traits, like volatile acidity.

For all of its natural, pastoral connotations, wine can very much be a manufactured product, processed to achieve a preconceived notion of how it should feel, smell and taste, and then rolled off the assembly line, year after year, as consistent and denatured as a potato chip or fast-food burger.

Yet we pay little attention to wine’s added ingredients, even as we have become hyper-conscious about what we eat. Twenty years ago, many Americans may have enjoyed food indiscriminately, but now they weigh the nutritional, environmental, humanitarian, aesthetic and even political consequences of what they cook and consume. Isn’t it time to devote the same careful attention to the wine we drink?

It’s no simple task. Unlike processed foods, wine is not required to have its ingredients listed on the label. This contributes to the belief that any wine is elemental, like fruits, vegetables and meats, and can’t be broken down into constituent parts. That’s far from the truth.

“It is very surprising how many discerning foodies will drink mass-produced, highly processed wines without batting an eyelid,” Isabelle Legeron, an educator and consultant who holds the rare title master of wine, wrote in an e-mail. “They just haven’t engaged with wine in the same way, yet.”

For the last two years, Ms. Legeron has held RAW, a fair in London that brings together producers of artisanal and natural wines with others in the trade and the public. All producers who take part are required to list any additives and processing techniques they have used.

The first question might be: Why are wineries so reluctant to document what goes into their wines? Ingredient labeling is voluntary, and very few wineries have stepped up. Bonny Doon Vineyard, Shinn Estate Vineyards and Ridge Vineyards deserve applause as notable exceptions.

Many wineries try to explain away their reluctance by arguing that consumers will be confused by long lists of ingredients, or even a short list of traditional but unexpected substances that have been used in winemaking for centuries. For example, artisanal producers who disdain adding enzymes may still try to clarify their wines with egg whites or isinglass, which is derived from fish bladders. Certainly vegans might want to know that information.

The fact is, some consumers make conscious decisions not to buy products when they see what goes into making them. I don’t want added sweeteners pervading the groceries I buy, for example. I love peanut butter, but won’t buy it if it contains anything more than peanuts and salt. Don’t all consumers deserve the same opportunity to make informed, considered judgments about wine?

At the same time, other consumers — the vast majority — continue to buy processed foods regardless of mysterious ingredients. They are motivated by cost, convenience and sensory gratification, or maybe they just don’t care. No doubt the same will be true with wine.

It’s not apparent whether additives in wine pose public-health risks. Nonetheless, if we want foods that are minimally processed, authentic expressions of what they purport to be (like cheese rather than processed cheese), then we want to be able to distinguish between wines that are relatively unmanipulated and those that are industrial products.

Most wineries have no interest in full disclosure. Just as with food manufacturers, they will have to be dragged into some form of honest representation of their product. Sadly, the responsibility is left largely to consumers to monitor what they buy and drink.

As a first step, it helps to think of wine as food. Concerns about where food comes from and how it’s grown, processed or raised ought to be extended to wine. If we ourselves don’t set standards for quality and authenticity, who will?

The New York Times

 

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