Day 30.1: Yeast
latecomer Ed Thralls over Wine Tonite! is figuring out the whole natural wine thing and wanted in on the proceedings, so i had do some research on yeast. Enjoy!
Part of the natural wine movement is one of the ongoing philosophical battles regarding the question to inoculate the must/juice with a starter culture of wine yeast or to allow the native, or “wild,” yeast to do its thing all by itself, with minimal to no human intervention.
Wild yeast is believed by some to enhance quality and certain characteristics of the wine. To be more specific, it is said to reflect the particular vineyard’s character in the wine more closely. This has to assume that the vineyard has some fairly distinctive qualities to begin with. For example, bacteria, which often accompany native flora, have a higher chance to take over during the longer fermentation, so the fruit will need good acid and good tannic structure to help battle this situation because native yeasts will be less tolerable to SO2. A wild yeast fermentation takes longer to start since the quantity of yeast in the vineyard and on the berries will be much less than when inoculated, will take longer to finish and will do so at a generally lower temperature. On a positive note, longer and slower fermentations can allow the yeast to have more of an impact on the fermentation adding enhanced texture and finesse to the wine. This is due to the fact that, in addition to converting sugar to alcohol, yeast also produces esters and compounds that contribute to flavor and aroma.
But, what is wild yeast, really? Most feel they aren’t really wild at all, but rather the well-known Saccharomyces that has set up residence in the winery or in the vineyard, often as a result of winery hygiene habits or pomace being recycled back amongst the vines. Regardless, native yeast is less predictable, less consistent and can often result in off-odors and flavors. Yeah, we all know, what might be off for me or you may taste like gold to someone else. Check out my post about petrol aromas caused by TDN in Riesling for another example.
On the other hand, fermentations inoculated directly with Saccharomyces increase the winemaker’s confidence that fermentations actually start and complete, are expedited in a timely manner, and are more predictable. This is mostly due to its tolerance to high alcohol and SO2 and its minimal negative by-products. These fermentations also will fun faster and often much hotter than those of native yeast. When you think about the investment and economics of growing and making wine this seems like a better insurance policy.
In an effort to see if I could distinguish the impact of wild yeast in natural wines, I tasted two fairly well-known offerings and compared them with wines of the same varietal, vintage and region but made with inoculated wine yeast. Note: this by no means was a scientific study, so draw your own conclusions. I just needed an excuse to drink some more wine. [Like that’s necessary]
2007 Edmeades Zinfandel Mendocino – This wine was very, very much fruit-forward on the nose that was almost “sweet,” but not in the residual sugar meaning, of course. There was absolutely no heat on the nose even though the ABV was a whopping 15.2%. The taste brought forth some very big blackberries, vanilla and medium spice at the finish. Overall, this was very smooth, velvety and full of fruit. The comparable wine displayed a lot of heat (15% ABV) and chocolate on the nose and was very smoky, jammy and finished with much bigger spice on the palate.
2006 Yangarra Shiraz McLaren Vale Single Vineyard – Right off the bat it was like I dove head first into a rosemary bush and got a few sprigs shoved up my snoz. I love rosemary and it’s a very distinctive aroma of the Syrah grape. Add that with some black olives and this was getting very interesting, indeed. The taste was also herbaceous with black fruit, slight minerality and medium spice on the finish. That was awesome! [Think The Chris Farley Show on SNL] The comparable wine from the same region displayed lavender, spice, blackberry and chocolate on the nose. The taste brought on more black fruit, jam with a shit ton of more spice, but a fabulous mouth feel, like you grew hair on the tongue.
So, were the fruitiness and distinct varietal characteristics of the natural wines due to the native yeast? Think about the Zinfandel where both contained 15% alcohol, yet I could only detect the heat on the faster/hotter fermenting wine yeast. Or think about the highly distinctive varietal characteristics of the Shiraz. Did the slower/cooler native yeast fermentation allow the yeast to pull more of these attributes from the fruit? I think I’ll need to do some more studying on this topic.
Ultimately, this sounds like the classic risk/reward scenario, where the significant economic risks of a stuck fermentation, off-odors and off-flavors are believed to be outweighed by the reward of more significant vineyard characteristics, elegant texture, pride in following a principle of less human intervention and marketability of the product to others sharing the same principles.
Yeast is as yeast does.
Follow day by day here: https://saignee.wordpress.com/31-days-of-natural-wine/
Up next: Dard et Ribo with Linecook415; or: VLM was WRONG (Day 30.2)