Monthly Archives: October 2018

Will micro-oxygenation render barrels obsolete?

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This wine makes me as happy as this essay.  It also neatly proves that micro-oxygenation will not make barrels obsolete.

I kinda like this essay.  It was a beautiful moment where all my facts and figures were easily recalled and the essay question itself provoked further questions from me (which I am now pursuing with different wineries to find out their experience).  I think the structure is pretty clear too.

This is the kind of moment (and feeling) I always wish for…

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It has been said that “micro-oxygenation might render expensive barrels obsolete”. What do you think is the future of micro-oxygenation, and what impact (if any) will this have on the wine industry?

With the advent of successful micro-oxygenation over the past few decades, this practice has increased in use and importance in the wine industry, and some have even suggested that micro-oxygenation might render expensive barrels obsolete. Micro-oxygenation is a process that mimics the minute oxygen exchange that usually happens over months in barrel. A micro-oxygenation meter can be used in tank to diffuse out tiny amounts (0.1mg/liter/month) of oxygen that can help polymerize tannins and stabilize color, and if oak flavor was also necessary, this could be added in the form of oak alternatives. There are advantages and disadvantages of using micro-oxygenation and depending on the size of the winery and skill of the winemaker, this technique could be used to replace barrels in some wineries.

One of the first advantages of micro-oxygenation is the relative cost to barrels. The initial capital outlay for a micro-oxygenation diffuser is high, with ongoing costs related to O2 tanks, but these expenses can be amortized over larger amounts of wine (depending on your tank size). There is also a significant savings of labor: moving and monitoring dozens of barrels relative to programing the micro-oxygenation diffuser in a single tank. Relative to that tank of wine divided into dozens of French oak barrels (costing around €1,200 for each new one), micro-oxygenation can be an economic option for some wineries, particularly larger wineries.

There is also an advantage of speed. Whereas the traditional oak barrels will naturally have individual rates of oxygen exchange (also depending on how many times that barrel has been used), a micro-oxygenation diffuser can be dialed in precisely to the level of O2 needed for a particular wine. With all of the wine in one tank, it is relatively easy to measure a wine, determine the rate of micro-oxygenation and set the diffuser to dispense that amount. Follow up monitoring and measurement in tank is relatively easy as well, compared to measuring dozens of barrels for the same metrics.

Despite these advantages, there still needs to be considerable practice and skill applied to use a micro-oxygenation meter. The science of tannin management is not fully understood and deliberate exposing a wine to oxygen always carries a risk of oxidation. This risk is further magnified by the volume of oxidizing an entire tank of wine relative to a single barrel. Calculating the rate of oxygen metering is not a straight formula, so a winemaker would need to understand the risks and gain considerable practice before completely forgoing barrels.

Some in the industry also question whether micro-oxygenation will result in a homogenization of styles of wine. For that same disadvantage that every traditional oak barrel will result in a slightly different wine (both from micro-oxygenation and from choice of origin/toast of the barrel), those differences can be blended to create a more complex wine than if everything was dosed from one tank. Even if a tank undergoing micro-oxygenation used a variety of flavor profiles of oak alternatives, the winemaker there will not have as much control to blend the final product to something more complex. A consistent wine style might be the aim of a larger volume of branded wines, but smaller operations might want to keep the variation (and subsequent potential complexity) of using smaller barrels.

Micro-oxygenation has several advantages including economics and speed, which might render this practice ideal for larger, branded wines. Just the same, using this technique requires considerable risk, which might be easier for the larger winey to absorb, and skill, which the larger winey might be able to attract. For these reasons, there seems to be no issue to use micro-oxygenation for larger, branded wines where consistency is key to the style. On the other hand, smaller wineries might still incur the higher expenses and longer maturation of using barrels for the same effect, if only because their consumers will accept more complexity and variation in wines.

The future impact of micro-oxygenation will be the continued quality improvement for branded wines at a relatively low cost, creating consistent wines with smooth tannins and appropriate color, and raising the bar at the value end of wine industry.

Wild versus commercial yeasts

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Oh, regrets.

The following is a timed essay that I did as practice for my upcoming Certified Wine Educator exam. I was halfway through the total allotted time (60 minutes) when I realized that I should have structured it to be compare/contrast wild and commercial yeast by topic rather than the clumsy way I did it here (which was everything-about-each-yeast-separately).

Yum. Yeast.

I guess that is why I practice.

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What is your take on the cultured vs. wild yeast topic? Is the claim of “wild yeast fermentation” valid, or does cultured yeast dominate the wineries of the world to the extent that wild yeasts are subdued?

A 2013 study by the University of British Columbia found that spontaneous fermentations with so-called “wild” yeasts were quickly overtaken by commercial yeast strains from the air, and these stronger strains could complete the fermentations to dryness. There were some flaws in the study, but the subsequent reporting raised the question: do wild yeasts matter?

It is an important question as many wineries claim to use ‘wild’ or ‘native’ yeast and use this as a marketing point of differentiation, yet this study, and other anecdotal evidence around the world, found that even without inoculating, the stronger, commercial yeast strains dominate fermentations. Commercial yeasts (generally Saccharomyces cerevisiae) are available for sale from any oenology store. These yeasts have been separated out by a microbiologist for various traits, multiplied, packaged and sold ready to add to your must. Wild yeasts, on the other hand, are native to a particular cellar. They live on the equipment, in the vineyard and in the air. The wild yeast are from other strains and oddly enough, the discussion of wild versus cultured has been so significant that oenology companies are now culturing wild yeast strains for sale.

Cultured yeasts have been an input to winemaking since Pasteur discovered the cause of fermentation in the 19th century. Many winemakers today will use cultured yeast for their specific properties (low foaming, low VA production or maybe tolerance to high alcohol) and it is this predictability that make cultured yeast so relevant. Being predictable means that the winemaker can control the quality and expression of the vineyard a little better. The winemaker at Smith-Madrone has said that he used wild ferments on his Pinot Noir for over 35 years before switching to cultured yeasts and cited that the cultured yeast allowed for a more pure expression of fruit.

Of course very few technical sheets or winemakers will openly cite what strain of commercial yeast they are using (but they would be open about other things like, which forest they get their barrels from) as it interferes with the consumers’ romantic notion of winemaking. There is also a fear of standardization: could wines that use the same yeasts (which impacts fermentation kinetics) start to taste the same?

Wild yeast fermentations certainly add complexity to a wine partially due to the different metabolites of these yeasts. Fermentation kinetics will also be different (might be slower to start and warm up) which will impart their own characteristics. Wild yeasts, when taken from the native environment, certainly saves money for the winery, which must be considered, and the romantic notion that wine is merely grapes carefully guided to the bottle will stay intact.

But most truly wild yeasts (non-Saccharomyces cerevisiae) have many drawbacks, mainly, that many of them die around 4-6% alcohol, implying that, even if a cellar has never had a packaged yeast brought into the area, Saccharomyces cerevisiae must finish the job anyway. This reason alone leaves the question of using a commercial yeast, which has the least amount of risk, as a no-brainer, but also that most aroma differences in wines made by wild versus natural yeasts are lost within the first 12 months, so again, why bother?

Knowing that a microbiologist can very easily separate our any yeast strains and reproduce it to use for a fermentation, it should be acknowledged that all yeast could really considered to be wild. Some have just been ‘tamed’. Also consider that the human hand is as much a part of the definition of terroir as the soil, the climate or even the grape variety. The winemakers’ job is to not destroy the individual terroir of the wine. If a wild fermentation starts to generate high amounts of volatile acidity because the yeasts are sluggish to get fermentation started, is this volatile acidity interfering with terroir or part of it?

In the end, it seems that the debate of wild yeast versus commercial yeasts is a philosophical debate. Studies have proven that wild yeasts and commercial yeasts co-exist in many fermentations and contribute their own positive and negative aspects to a finished wine, so the choice depends on the style of wine you are making and for what commercial segment of the market.