If last year was Darth Vader - all about extraction, enzymes, neutral oak chips and depth of color - this year is more zen Yoda. I basically said to the yeast: “do or do not, there is no try”. In short, ‘08 is all about the old wine cliche “let the wine make itself”.
The wine is turing out wonderfully, and for that I blame Joel Peterson. Earlier this spring I had a chance to spend a few nights chatting with Joel and Morgan, tasting wines blind and talking shop while Morgan prepared for his Masters of Wine exam. I’m happy and proud to report that Morgan, a fellow blogger and winemaker, passed.
He is now one of less than 30 (correct me if I’m off here) American MWs. And Morgan is still a few years short of 30. Quite the accomplishment, to say the least! You won’t find a more down to earth, unpretentious MW anywhere. And that’s just the way it should be.
Anyway, during one of our conversations Joel asked me what I thought about native yeast ferments. I repeated what I was taught at Davis: that native ferments were unreliable, and that more likely than not the yeasts that eventually ended up doing the heavy lifting were cultured ones already present in the winery, not in the vineyards.
30 Yeast Enter, 4 Yeast Breed
Joel nodded and then proceeded to tell me about a series of intriguing yeast studies he oversaw at Ravenswood. A few years back he hired a yeast geneticist to study the native yeast populations at various vineyards under contract at Ravenswood. The geneticist catalogued each of the species of yeast he found and then tracked the development of each through fermentation. He did this over multiple seasons.
What the geneticist found was that around 30 species came in to the winery on roughly 5% of the grapes, and that only 4 ended up fermenting the juice. Each of the 4 yeast “winners” would then split up the ferment. For example, one species might feast from 20 to 13 Brix, and then would be outcompeted by a second yeast which was better suited to the now more alcoholic conditions of the must. These results held year over year, and could explain why many folks tend to favor native yeast ferments, lauding them as “more complex”.
Evidence For Terroir
But for me the real relevation was this: the 4 yeasts strains that ended up being “winners” and dominating the fermentation varied each and every year of the study. Indeed, the pool from which the victors came varied each year as well. The assumption is that conditions during the growing season select for different species each year. As Joel pointed out, yeast are fungi after all, and thus are heavily influenced by weather conditions.
This is a profound finding, and is perfect evidence of terroir at work. It was also enough to convince me to rethink my position on natural vs. cultivated yeasts in winemaking.
Joel has graciously given me permission to share his research, and hopefully those of you out there who have been reticent about experimenting with native yeasts will give it a go. As for me, I’m now one of the converted.
The labs for the grapes were similar to last year, with acids being noticeably higher. The big three looked like this:
- Brix: soaked up to 27.4
- TA: 7.5 g/L
- pH: 3.44
Free Wine!
The only adjustment I made prior to ferment was to rehydrate. This is also the only similarity between this year’s recipe and last. Total H2O add back was less than 12%, with the rule of thumb being that anything less than 20% will not dilute flavor.
Some winemakers prefer to bleed off an equal amount of juice prior to the rehydration (as I did last year), and some even bleed off more than is added to concentrate the must further. The fruit this year suffered from some pretty severe desiccation however, so I felt that not only would my addition of Jesus Units this year help tame the high sugar, but would also bring about needed balance. Thus I did not bleed. Hey, it’s free wine!
After de-stemming I dosed the wine with ~30 ppm SO2 to stun the various strains of yeast (many of which would be responsible for off-odors and creation of volatile acidity) and initiated a cold soak with the addition of dry ice. Temps were held around 55 degrees for 4 days and then I allowed the must to gradually come up to ambient temps. 5 days after de-stemming fermentation began and is just now winding down. Peak temp observed was 87 degrees (which is good for maintaining some of the more delicate volatile aromas generated during the ferment, but not optimal for color) I’ll be pressing off tomorrow and going to barrel.
Interestingly, I was able to recognize 4 different stages during the ferment, which I assume coincided with the points at which the different yeast strains dominated. There was a slightly stinky sulfur stage, and a spicy/earthy stage bookended by two floral and fruity stages. Good times.
A Successful Experiment
As an experiment with an eye towards quality and complexity, so far this one has been extremely successful. There were no issues with the ferment, the “off-odors” generated by the native yeast stand a very high chance of contributing a complexity to this year’s wine lacking in the ‘07, and inputs and interventions were minimal. This makes for less work on my part both now and down the road.
And finally, given Joel’s research into native yeasts, I believe that I can say with very high confidence that this vintage reflects the terroir of Rebecca’s vineyard and not just be blowing marketing sunshine up anyone’s tailpipe.
My thanks again to Joel and Morgan for the wine, food and the invaluable advice.
Pics and a video coming soon!
Alice Feiring would be so proud of you!!!! Congrats on the Harvest and seemingly seemless vinification. It’s Miller Time!
seamless.
LOL.
Thanks Patrick!
Hey Josh!
I think it’s cool that you gave the native yeasts a chance at doing their job. My winemaking classes at Napa Valley College basically said the same thing: that you’d have one yeast strain doing the first ferment, followed by another picking up when the first strain started flagging due to the increased alcohol in the must.
Us thirsty souls here at Wine Biz Radio are wondering where our samples are, however!
Glad to see that another vintage is about to be put to bed for you. Congrats!
Great post and well laid out. Should be fun to taste through your library one day!
Bootiful. Rebecca’s East fermented dry in nine days with a VA of .042. How about dem apples. Tastes excellent if perhaps a bit high on the alkeehaul.
Rebecca’s West is dry, pressed, and barreled down yesterday. Still waiting on final lab numbers.
Yay native yeast!!
This is a wonderfully written article. Kudos. Cannot wait to taste.
Does that mean we’ll get marketing sunshine in the future? I’m game, as long as it’s not up the tailpipe…
Congrats on the good work.
Mr. Pinot has done it again! Excellent experiment, I will be excited to taste the results when you incorporate the Pommard into the program.
Long live the sugar eaters, whether stinky, earthy or floral they are the BOMB!
Hi Josh…we too here at the Oak That Is Twisted have jumped head first into native fermentations this year after some small experiments over the last couple of years. In fact, with over 20 red lots in so far this year, only 2 have been inoculated with a “commercial” yeast. So far everything’s gone dry and only one moderately high VA. A leap of faith for sure, but it is definitely bringing some excitement back into the equation.
As far as the cold soak with dry ice goes…a buddy of mine decided this year in an extremely brilliant stroke of genius-like simplicity, that he would make any H2O additions (in order to ensure fermentation, of course) in the form of ice, thereby killing the proverbial two birds with a bunch of frozen H2O stones…needless to say, my 10 years head start on him in making wine has been humbled.
Seriously I love Fermento’s idea.
Congrats on the current harvest!
Fermento,
Love the ice solution! Hey, even better: acidulate the cubes to 6 g/L to avoid acid adjustments as well.
Randy,
Not really happy with the Darth Vader wine at this point. More intervention will be necessary (think fining) before I’m ready to present it to the world. Enzymes just pulled out too many bitter phenolics.
thank you so much for sharing this level of detail
it is so refreshing to be able to share this kind of information, and really builds trust
I REALLY hope I will get to try your wines over here in the UK at some stage
Josh, big, big thanks for yr candid sharing! I dove into technical winemaking basics for ‘06 crush with three projects at Crushpad, primarily Alan ‘Cellar Rat’ Baker’s Anderson Valley Pinot, & I was happy that my ‘reckless’ pushing got Alan to take a chance on letting at least one out of four barrels ‘go native’– of course, I had only one case’s worth of money on the line, so I’m bonded to Alan for his courage under all sorts of pressure.
My next step was networking in Mendoza as crush ‘08 loomed in the Southern Hemisphere, & as luck wd have it, I made friends with the strictest non-interventionist in Maipú. I’m hoping I can fund his taking some different chances, my problem is learning the biz side & finding the right partner to help me sell some of this stuff…we need to learn from the Darth Vaders too, y’know! Looking fwd to meeting & trying yr ‘caldos’!
PS– how early in th season to have brix low enough not to need amelioration? Anybody trying to be that strict? Or are/were things phenolically just too too green to try it?
Great and interesting post. Can you please clarify one point regarding the Ravenswood experiments? Are you talking about different yeast STRAINS (i.e. genetically different variations of S. cerevisiae) or different yeast SPECIES (i.e. S. cerevisiae vs. S. bayanus vs. others still)? By what means specifically were the yeast differentiated? Sometimes multiple yeast with the same karyotype and mtDNA analysis (i.e. genetically identical for all intensive purposes) have different DNA fingerprints by DNA hybridization. Thus it’s really just degrees of different and how minutely you want to catergorize and split hairs By single nucleotides? Just curious. Have been reading/ writing about yeast strains, too. Ribereau-Gayon has an excellent chapter in the Handbook of Enology. PLease let me know. Interesting stuff.
Hi Kerith,
Both different species (bayanus cerevisiae etc.) and different strains (of mostly cerevisiae) were found each year.
As to the specifics of determination and differentiation, I’d have to get the paper Constellation produced to answer that. Our talks, while detailed, were not exhaustive.
Your comment about splitting hairs is well taken, and I’ll see what I can learn from Joel and post it here in the comments.
Thanks for the comment and the kind words.
Josh
Thanks for a speedy reply. Good to know that cutting edge DNA technology- when not being used for really important stuff ( i.e differentiating the DNA of 5 potential baby daddies for a prostitute on Jerry Springer) - is advancing wine science. Great stuff.
[...] Hermseyer of Capozzi Winery, recently wrote about genetic typing of yeast species and strains at vineyards contracted by Ravenswood. Over [...]
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