We all love wine, different taste of wine. Is it safe to assume most people understand that a little bit of character from Brettanomyces enhances the complexity of a wine? Sure everyone’s threshold is slightly different, but when 4-ethylphenol or 4-ethylguaiacol hover around the threshold an already wonderful wine can become sublime and an ordinary wine compelling. In other words, flavor compounds generally recognized as a fault can often enhance and augment a wine helping the whole be greater than the sum of the parts. Of course it is a risky line to walk, but I think most would agree with this premise.
It is with this in mind that I follow-up the recent post regarding picking by flavors. If it is true that flavor compounds generally recognized as a fault can often enhance and augment a wine than is it true for methoxypyrazine specifically? While working with Merlot and Cabernet Sauvignon this compound is something we often ponder since it contributes to the relatively unsavory bell pepper aroma.
Studies (Allen et. al. (1991); Lacey et. al.(1991)) with white wine have shown that when methoxypyrazine was added to wine that otherwise had none, concentrations as low as 1 part per trillion significantly influenced the aroma of a methoxypyrazine-free white wine (emphasis mine) but was not necessarily perceived as pyrazine (bell pepper, chili, ect.) per se. In fact the threshold in this study was determined to be around 8 ppt in white wine. Typically aromas such as these have even higher thresholds in red wine. Why bring this up? Well the problem with scientific studies is that they understandably avoid more subjective conclusions regarding perceived quality and limit themselves to analytical quantification. What interests me is that the compound contributed to the overall aroma as low as 1 ppt, but while scores for veggie increased with increasing concentrations of pyrazine, there was no significant difference between 1, 2, 4, and 6 ppt. It was not until 8 ppt that the tasters effectively said, Whoa, now that is different.
Therefore since the tasters do not indicate whether or not they liked the aroma, I am free to use this study amongst other corroborating evidence to make my own speculation about aroma contribution. This is a 3 paragraph intro to get to this point: at these low levels the contribution to the aroma certainly could have been positive contribution to complexity, to interest, to intrigue in the wine.
Don’t let their term used to train the tasters – veggie – throw you off track. Why shouldn’t the pyrazine compounds improve and complex the aromas and flavors of the wine that would otherwise have none? Indeed, Allen has said elsewhere in regards to Sauvignon blanc: [pyrazine] concentration in Sauvignon blanc wines is typically 5-30 ng/L. Below 5-10 ng/L, the aroma is subdued; at 15-20 ng/L it provides an aroma that is distinctive, characteristic of the grape variety, and frequently balanced with other flavor components in the wine; at only 30 ng/L it begins to be rank and overpowering. Too little of this compound leads to an undistinguished wine, but too much gives one that is unbalanced (emphasis mine).