An Ode to Yogurt in Chablis
They don't make things like they used to...
With the tidal-wave of growth in low-intervention winemaking, many of my tasting groups frequently debate whether the barnyard aromas in a certain wine enhance its character or mask the fruit entirely; or whether a wine is "lifted" or edging closer to overpriced Kombucha. While I'm glad that discussions about whether the mere presence of certain “flaws” disqualify a wine from being considered well-made or beautiful are mostly behind us, I find that discussions of acceptable levels Brettanomyces and volatile acidity still dominate professional conversations in these arenas. So, I’d like to highlight a lesser-discussed wine fault that is deserving of some time in the spotlight: ethyl lactate.
First, Some Chemistry…
When bacteria convert malic acid to lactic acid, the softening of the wine is often attributed to this shift in the predominant acids. During malolactic conversion (ML), the wine’s pH increases because lactic acid is a weaker acid than malic acid. Acids lower pH by donating protons (H+), but strong acids, like hydrochloric acid, readily donate all their protons, while weaker acids, like lactic acid, only partially dissociate. At the typical pH of wine (∼3.4), most lactic acid remains undissociated. However, as the pH rises (∼3.9), more lactic acid dissociates into its anion, lactate. In the presence of ethyl alcohol (ethanol), this lactate undergoes esterification, resulting in the formation of ethyl lactate.
Ethyl Lactate and Yogurt
Most of the time, ethyl lactate is present in small amounts in wine and contributes to its fruity bouquet. Similar to its cousin, ethyl acetate, it will add complexity and enhance aromas present in the wine at low concentrations. As the concentration of ethyl lactate increases, tasters will describe the wine as creamy, buttery, or with a yogurt characteristic. When this yogurt character begins to overpower other aromas in the wine, the conversation shifts to whether the wine is flawed—in other words, should the winemaker have intervened??
Yogurt and Chablis
Years ago, I sat on the front porch of an accomplished sommelier friend's house on a hot summer day, sipping an old Chablis. (Apologies to all Sommeliers—I’m terrible at remembering labels, so you’ll have to trust me that it was a classic example). With age, most of the youthful fruit flavors associated with Chablis had faded. What remained was the hallmark flinty and oyster shell character, alongside delicate floral notes. However, there was also a pronounced "lactic" note. To me, it seemed a shame the wine had undergone ML, as the yogurt-like quality distracted from its remaining delicate traits. Yet, my Sommelier friend waxed poetic about it, lamenting that Chablis just doesn’t taste like that anymore. While I don't remember the exact dialogue of our conversation that followed, it went something like this:
"Of course it doesn't. This fruit was likely picked with elevated malic acid levels. High malic acid means higher lactic acid when it undergoes ML, which in turn leads to high ethyl lactate - we're taught to avoid that in winemaking."
I've thought a lot about the ensuing conversation over the years. Why doesn’t Chablis taste like yogurt anymore? Is it simply that global warming has reduced the high malic acid levels traditionally found in Chablis, or is it a deliberate choice by winemakers to embrace a more global style by picking riper fruit? This wine was made before inoculating with lactic acid bacteria was commonplace. Perhaps winemakers are now more vigilant about preventing spontaneous ML in Chablis, or even avoiding ML altogether, to preserve the crisp acidity we associate with the region.
Yogurt and Terroir
In all my conversations about wine flaws, one question consistently arises: are flaws reflective of terroir, or do they obscure it? Early in my winemaking career in the south of France, I strongly associated Syrah with Brett. Later, during a vintage in Australia, I was scolded by a winemaker for failing to identify Shiraz barrels while blind-tasting unless they had Brett in them. His argument: How could Brett be a part of terroir if you can make a Bretty wine anywhere in the world? The same argument can be made for wines with high volatile acidity.
With ethyl lactate, no such argument could be made. It’s hard to get the yogurt-y ethyl lactate character without high malic acid. There are few places in the world where grapes can be harvested with the level of malic acid needed to get the yogurt character. We just don't find wines like that anymore.
