Clinically clean wines and the fear of funk

©Copyright Ben Rotter 2006-2008


In modern times there has been a huge and positive push towards making technically fault-free (i.e., “clean”) wines. This has largely been academically induced through the world’s leading oenological institutes, where winemaking faults have been studied and categorised in a relatively objective sense, and winemaking approaches which tend to safely restrict wine faults are advocated.

This clean, low-risk winemaking is perhaps best exemplified by the institutional fears of producing wine at high pH, fermenting with indigenous MLB or indigenous yeast, or bottling wine susceptible to further yeast or microbial action (for e.g., unfiltered, with high malic/sugar content, or low SO2). The winemaking used to combat such risks (acidifying to ensure lower pH’s, 0.45 micron filtration, full MLF, etc) are deemed fairly acceptable for basic high-volume wine, but numerous wine lovers complain that wines made for the premium market should not be restricted by such low-risk winemaking approaches. They claim such approaches often result in “boring” wines which taste similar and “lack soul”.

Defining faults

There is a general consensus in the wine world of what constitutes a fault. Faults include, but are not limited to:

  • Excessive oxidation
  • Excessive volatile acidity (i.e., generally, acetic acid or ethyl acetate concentrations well above threshold)
  • Microbial spoilage (fermentation by undesirable lactic acid bacteria (LAB), fermentation by unwanted/undesirable yeast, excessive production of Brettanomyces yeast byproducts, and in-bottle fermentation of any kind due to microbial instability)
  • Severe lack of clarity
  • Reductive problems (for e.g., hydrogen sulphide or mercaptans)

  • As a consequence of the oenological education of faults, the world of wine has largely been transformed for the better over the last thirty years, such that it is now difficult for the average consumer to find mainstream commercial wines that exhibit faults.

    Faults are Style and Threshold Specific

    It should be kept in mind, however, that the (un)acceptance of these faults is largely dependent on wine style. Deliberately oxidised styles such as vin jaune, Sherry, Madeira, and Tokaji prove that, whilst perhaps not widely popular at the present time, oxidised wine styles are still accepted and enjoyed by some. Such wines are not considered spoiled or at fault by oxidation, since this is a part of the intended style. To an extent, the same might be said of limited reductive notes (e.g., the "earthy/smoky/flinty/sea-air" notes associated with volatile sulphur compounds). Similarly, whilst VA is never acceptable at levels well above threshold, it remains an acceptable and even welcome component at unusually high levels in some wine styles (for e.g., "big" Australian Shiraz). With regard to microbial faults specifically, it might be completely unacceptable for re-fermentation to occur in bottle, but the acceptability of Brett-related aromas is something that remains debated for particular styles. (It might even be argued that Brett character only becomes a fault after the ratio of concentrations of specific Brett-related compounds to other aromatic compounds in the wine rise above a specific level. For example, wines with 4-ethylguaiacol (4-EG) concentrations much more perceptible (higher) than 4-ethylphenol (4-EP) concentrations result in more appealing spicy/smoky aromas than the despised medicinal/Band-Aid aromatic profile, and therefore do not tend to be considered faulty. There is still much debate in the wine and research community over whether any Brett character can be a positive thing at all, since 4-EP/4-EG may result from non-Brett sources.) Whilst there is widespread agreement on what constitutes a fault, it clearly remains style and threshold specific.

    Risk and Interest

    Some wine lovers argue that winemakers who take risks tend to make more interesting wines. Wines that are made in a low-risk manner in order to avoid faults and obtain a cleaner product are sometimes criticised for their lack of interest or complexity. In fact, disdain for low-risk winemaking is more widespread than might initially seem apparent.

    No-one wants to drink wine half-way to vinegar, and there are few wine lovers who like their wine so Brett ridden that it is devoid of fruit and smells solely of shit or dirty socks. However, some tasters like to see a bit of funk - it provides interest and complexity. The fact is that, for example, a little VA below threshold may lift a wine's nose, that some people adore what they perceive as barnyardy Brett character, and that the complexity of aromas provided by indigenous ferments (both by yeast and MLB) may significantly enhance a wine's appeal. The cult success of such wines as Chateau Musar is testament to the fact that even considerable VA, oxidation, and/or Brett character can be enjoyed. This is the grey area between funky and faulty. The difficulty is in getting the appropriate level of "funk" before getting into the definitively "faulty" zone. Aiming for a bit of funk inevitably involves an element of risk: indigenous ferments can result in excessively high VA or stuck ferments with subsequent LAB-associated problems, there exists little control over resident Brett, and allowing VA to push towards sensory thresholds can be difficult to get right.

    The issue of filtration provides a further useful example of this low-risk approach to winemaking and its potential disadvantages. Serious clarity problems are generally regarded as unacceptable, not only for reasons of aesthetics but also for the potential impacts the suspended solids might have on wine quality. However, some argue that premium clarity and tartrate stability often come at the price of stripped wine aromatics and body due to comparatively rougher handling, filtration and fining. Indeed, sterile filtration is often cited as a process which practically assures against microbial spoilage, yet "denudes" wine of character. Indeed, there is evidence that sterile filtration may reduce a wine's macromolecule content, modifying mouthfeel characteristics. Wines which are left unfined and unfiltered might have less fruit character and less precision, but more complexity and improved mouthfeel (most likely due to yeast autolysis products, which are removed by filtration or fining processes). It might be further argued that the fear of instability often leads to sterile filtration - even if purely driven by financial security.

    The case for risk

    The author is of the opinion that the fear associated with higher risk winemaking is often unjustifiably greater than the reality. The risks of microbial instability may not actually be as great as some would have us believe. There are winemakers who routinely produce unfiltered, indigenous fermented wines which remain microbially stable (and this is not limited to big reds with high alcohol and phenolic levels). The accepted popular limits for microbial stability such as a maximum pH 3.6 threshold or a minimum 0.6 mg/l molecular SO2 (dry wines) are only safe rules of thumb, and therefore do not apply to many situations.

    The central problem over the issue of low-risk winemaking is control, and ultimately a question of whether the winemaker is willing to potentially increase quality at the expense of an equally possible (and sometimes more likely) degradation in quality of the end-product. Cases of mild failure may result in a loss of freshness, overtly off-putting funky characters, and microbial instability. In the worst cases, vinegar, death of character through severe oxidation, and exploding bottles of wine are disasters. Taking such risks is treading in the grey area of what one can "get away with". This requires a sound understanding of wine style and the potential risks associated with higher risk winemaking activities. The key is in understanding your product and managing risk, while pushing the limit within that risk-zone. For such an approach to work successfully, fruit must be healthy (no rot) and low pH's and high tannins help. In the case of no fining/filtering, winemakers should have an idea of target minimum sugar and malic acid levels for each batch/vintage, above which levels they are unwilling to push the risk envelope. Likewise, a knowledge of how microbial and yeast inhibitors (such as alcohol, pH, SO2, storage temperature) work in synergy can be particularly helpful.

    Perhaps it’s time for a cultural change in winemaking wherein winemakers risk things a bit more? There've been a worldwide drive towards complexity through blending, oak and lees influence, and improved fruit selection, but what about complexity in tertiary flavours through more risky handling of élevage approaches? Cool, cultured ferments can successfully yield clean and aromatically precise wines, but do they really result in wines as interesting as those which have had warm or funky ferments with higher levels of suspended solids in the must? Is the acidification habitually practised in warmer climates (used to lower pH for conditions of microbial stability) really better if it results in a wine of inferior balance compared with the higher pH, less stable wine it might otherwise have become? Perhaps a less ageworthy wine with a higher risk of microbial infection is a better option than the alternative?

    Of course, this approach can be difficult in a commercial environment which demands safe returns, particularly for those who produce large volumes. However, even in such cases a small sub-budget could be set aside for trial "funky" batches (for e.g., 10% of production on small select batches/parcels). Non-commercial winemakers have potentially much less to lose. If one were to single out the cries coming from disgruntled wine lovers at this point in time, one of the loudest might well be the growing disdain for clean, technically correct, fruit-driven wines that disappoint in terms of interest. Why not experiment a bit more?

    Funking it up in practice

    A list of ways to experiment:

  • Minimise acidification on warm climate fruit (risk pushing the pH 3.6 safety margin to somewhere pH <3.8)
  • Wild/indigenous yeast and/or wild/indigenous MLF (expect long time scales, and be willing to pay the attention to detail necessary, but potentially gain the rewards of superior complexity and mouthfeel). This could involve culturing your own indigenous strain through strain selection and/or the practise of blending wild+ and wild- wines together
  • Minimise filtration (maintain character and mouthfeel at the risk of potential bottle instability). Aim for residual sugar < 0.3 g/l and ideally cell counts maintained < 100 cells/ml throughout the life of the wine.
  • Conduct warmer ferments with aromatic whites
  • Ferment with increased levels of suspended solids in the must (for whites)
  • Increase the handling of must and wine toward a more (though not entirely) oxidative approach
  • Allow Brett development (for e.g., retention of Brett+ barrels) to a certain point before hitting with SO2 and filtering (This is more controversial, since what many tasters consider to be a Brett-related character may not actually be of Brett-origin. This leaves uncertainty as to whether the significant influence of Brett on wine aromatics can ever be considered positive.)

  • However, the following situations are undesirable and winemakers should be wary of them with regards to funky winemaking:

  • Very low SO2 levels
  • Strongly oxidative élevage techniques
  • Rough (oxidative) wine handling
  • Use of high-risk techniques using fruit in poor condition
  • Use of wild/indigenous bacteria/yeast when a lack of synergy exists between conditions of high alcohol, low pH, high SO2 and low microbial/yeast populations
  • Low nutrient supply issues