I recently watched a video where Russel Bevan and Tor Kenward were having a discussion. One area that came up was the topic of co-fermentation. Tor claimed that co-fermenting different varietals together completely changed them and brought out flavors and integrated them in ways blending them after separate fermentation’s couldn’t do. Russell adamantly disagreed and said co-fermenting makes no difference.
Does anyone have a view on the science behind co-fermentation or if anyone has done trials to really compare to blending to see if it makes a difference?
I’m not sure about the claim regarding changing flavors and integrating them, but the rationale I have always heard for co-fermenting Syrah and Viognier is that it helps stabilize the color.
The viognier contains colorless flavanols from the skins that extract and conjugate with the extreme concentration of syrah’s anthocyanin color molecules. Basically, the theory is that viognier helps stabilize syrah’s color; the condensation reactions between viognier’s flavanols and syrah’s anthocyanins form highly stable polymerized molecules that stay with the wine for life. Once these polymers form, they don’t degrade through normal oxidation reactions.
There is also a shift in the color spectrum of a syrah that has co-fermented with viognier. Normally, syrah has a deep ruby color. Once viognier is thrown into the mix for the complex reactions to form, the color will shift from deep ruby to saturated purple/blue. This has a lot to do with light absorption/re-emission quantum chemistry of the anthocyanin complex with the viognier flavanols altering the polarity and electron flow of the multi-six carbon phenol ring that forms the anthocyanim molecule, thus altering the molar extinction coefficient. The absorption of green spectrum light (520nm) by these condensed molecules causes re-emission of red spectrum 700nm plus a stronger re-emission at 420nm (deep purple/blue). That’s why the co-fermented syrah/viognier blend works magically, creating an inkier wine. It’s strange how this all works, taking a dark grape and cutting it with a white variety, and end up making a wine that is even darker. That’s the complexity of quantum chemistry, which I had the pleasure of studying many years ago while obtaining my biochemistry degree.
Now, I should say that this co-fermentation phenomena has been a very traditional winemaking approach taken in the northern rhone valley of France. Through centuries of trial-and-error with many other varietals of the region, the combination of syrah with viognier became the standard. This was decided by making better wine, not by having knowledge of the complex chemistry. The chemistry came along much later to explain why it worked so well.“
I find Russell’s assertation hard to believe, I would tweak a bit to say they result in different flavors, and not necessarily better, but possibly, when you co-ferment vs. blend.
White grapes definitely set color, but Viognier also offers an aromatic and textural profile when you get to a higher % which is why I tried Rousanne, to avoid the peachy aspect. Still recall a good discussion where Justin from Saxum was active on the co-ferment topic
I don’t know a thing about blending different grape varieties together but I do know that putting a 100% whole cluster cuvee together with a completely destemmed one does not make it taste like a 50% whole cluster fermentation. I realize these are quite different ventures but I would think my example informs on the other. Much in the way meat seasoned while cooking tastes different than meat seasoned at the end of cooking. Seems logical to me that co-fermentation would produce different aromas and flavors than post-fermentation blending.
Jim and Marcus - Thanks for those interesting observations.
In Cote Rotie, the Northern Rhone appellation where the cofermentation with viognier is most common, it’s rarely over 3% or 5%. I can’t think of a Cote Rotie that had an overtly peachy aroma, but of course it’s a very different environment.
The Viognier really comes across in the Domaine Faury (now Lionel Faury) Cote Rotie, although it’s more high-toned florals than stone fruit. I think they use 10-11%.
For what it’s worth, the 2019 Halcón Alturas has 5% Viognier and no peachy anything either from my recollection (and no mention of anything of the sort in any CT note).
I’m always wary when someone says ‘better’ when that is so subjective. ‘Different’ is my word of choice here.
In Cote Rotie, I beleive you are able to add up to 20% Viognier.
One main reason that Viognier is co-fermented in Cote Rotie - syrah is ‘challenged’ to get ripe enough and therefore co-fermenting with viognier adds much needed sugar and decreases the overall acidity.
And as far as ‘peach’ or ‘floral’ goes, does it happen? The answer is yes . . .and no . . .and maybe. Just like everything else wine related, the cause and effect are difficult to confirm most of the time . . .
Reminds me of wineries who talk about fermenting and/or aging in concrete and state that this adds a note of ‘minerality’ - leading the witness . . .
For what it’s worth, I was listening to John Kongsgaard on the I’ll Drink to That podcast (really great podcast), and I believe he mentioned that you get very different results if you co-ferment vs merely blend.
Yes, at 20% it would really stand out less it was some pretty understated Viognier and it’s usually fairly ripe since, as Larry mentioned, it ripens earlier and was originally partly used to increase the sugar in the must a bit.
The Faury I mentioned and Guigal’s La Mouline have the highest percentage of Viognier of the Cote Roties I’ve tried (that I recall) at 10-11%. I think Faury made a bottling one year that had 15% (I haven’t tasted it).
My current two syrahs have 8 and 9% co-fermented - why did I do this? First and foremost, I broke the lots into 2 separate fermentors - one with a larger percentage of viognier and one with zero, all 100% whole cluster, foot stomped aggressively by me and then fermented with their stems, In both cases, I ended up blending some of the non-viognier lot with the one that had a lot of viognier. Why? Because, TO ME, the blend was ‘more interesting’ than either of its pieces. Would others find that to be the case? Maybe . . . I also think it’s cool to ferment red grapes with white ones - I love the aesthetics of it.
It’s always wise to avoid drawing broad conclusions from minimal evidence. I’m sure in Russell’s experience playing around he found no difference in his particular experiments. In the spectrum of possibilities, we see above experience where cofermenting gives inferior results. We have factual evidence with some examples where and how it works… It shouldn’t be surprising there are cases it makes either no difference or no discernible difference.
There are certainly plenty of other examples in more traditional winemaking of a certain percentage of white grapes interplanted intentionally. That includes red Burgundy. In California, mixed black field blends often had/have a few white varieties in the mix. I see this in more off the beaten path areas of Spain, Portugal, Italy, etc. The move to increasing quality put this and other practices in the dust bin. I think we’re now seeing a lot of reflection on what discarded practices have their usefulness in certain circumstances. Kudos to the nimble, innovative winemakers.
Stabilizing and fixing color sounds more reasonable. I’ve read many times how co-fermenting a little bit of Viognier with a Syrah makes it (in a seemingly magical fashion) deeper and darker in color, but that doesn’t seem to be the case. I’ve read one academic research where they co-fermented small batches of Syrah with varying amounts of Viognier and it always resulted in a lighter / less opaque wine. Especially at 20% the color was noticeably lighter and more translucent. However, fixing the color and making it more resistant against oxidative degeneration sounds more sensible, because that’s something you wouldn’t see immediately after making the wine, but after many years. If it really works like this, after a decade or two a Syrah co-fermented with Viognier might appear much darker compared to a 100% Syrah, which would explain why some people errorneously think adding a Viognier makes a Syrah become darker in color.
Hermitage allows up to 15% of Marsanne and/or Roussanne, although seems to be less common than co-fermenting with Vigonier in Cote Rotie. I think Tablas Creek in Paso Robles also co-ferments Roussanne with some Syrah lots although I’m not sure they have ever released those lots (rather they use them in the Esprit blends).
Aren’t lots of very old “Zinfandel” vineyards in California a field blend of multiple varieties. I assume that (because it has only been recently that people actually knew what the field blends consisted of) these field blends have traditionally been co-fermented. From the classic old vine vineyards from which I have had “Zinfandel”, it doesn’t seem to have hurt the wine.
They aren’t picking at crazy brix like Vio in WA/CA. I can get Vio notes off La Mouline with it’s 10%, but agree with the Old World assertion, as I was more speaking from a New World perspective due to the reference.
We did from 2008-2016, from a vineyard in the WV. 100% whole cluster, treaded with only modest aggression , and Viognier varying from 16% in 2008 and 2009 to about 6% in one cuvee.
Site specific though…because I just had one site to choose from.
It might be fun to do a Syrah tasting at some point and look at what stems and Viognier offer.
, and Viognier varying from 16% in 2008 and 2009 to about 6% in one cuvee.