Comments on: Yeasts Gone Wild: Part 1. http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/ searching for truth in wine Thu, 11 Mar 2010 08:04:20 +0000 http://wordpress.org/?v=abc By: Nick http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-558 Nick Thu, 20 Nov 2008 01:26:36 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-558 In Principles and Practices (Boulton, Singleton et al.), the concurring opinion to yours was published back in 96. This is (was?) a principle text used for teaching at UCDavis, and though published in 96, has no information (on our yeast topic) newer than 90. Professor emeritus Mortimer, a yeast geneticist from UC Berkeley, concluded a study of uninoculated fermentations in 93 or 94 I think. He found that: Almost all of the vineyards he looked at had S. cereviseae on the grape surface. The yeast doing the fermenting were the same as those found on the grapes. The average number of different S. cereviseae strains per fermentatuion was four. Each strain dominated a different part of the fermentation. No contention was made vis the flavor contribution from these yeasts. The study was contributing information to the possible source of the yeast, and the number of different strains present. What any decent UC VEN student can tell you is that the S. cereviseae hanging out on the grape skin is biding its time: They are metabolising aerobically, taking one six carbon sugar and producing 32 ATP, and doing this very slowly, very stingily, making the most of a very scarce resource. When a grape skin is compromised and abundant six carbon sugars become available, S. cereviseae switches its metabolism to fermentative, and though only making 2 ATP per six carbon sugar, quickly overwhelms all other microoganisms by dint of sheer reproductive rate. That there are very few S. cereviseae on the grape surface proves nothing. They are fully capable in such small numbers to outcompete the competition. Not that I'm taking sides. I have more on this. Does anyone have any further info on Mortimer's research and any follow up studies? In Principles and Practices (Boulton, Singleton et al.), the concurring opinion to yours was published back in 96. This is (was?) a principle text used for teaching at UCDavis, and though published in 96, has no information (on our yeast topic) newer than 90. Professor emeritus Mortimer, a yeast geneticist from UC Berkeley, concluded a study of uninoculated fermentations in 93 or 94 I think. He found that: Almost all of the vineyards he looked at had S. cereviseae on the grape surface. The yeast doing the fermenting were the same as those found on the grapes. The average number of different S. cereviseae strains per fermentatuion was four. Each strain dominated a different part of the fermentation.
No contention was made vis the flavor contribution from these yeasts. The study was contributing information to the possible source of the yeast, and the number of different strains present.
What any decent UC VEN student can tell you is that the S. cereviseae hanging out on the grape skin is biding its time: They are metabolising aerobically, taking one six carbon sugar and producing 32 ATP, and doing this very slowly, very stingily, making the most of a very scarce resource. When a grape skin is compromised and abundant six carbon sugars become available, S. cereviseae switches its metabolism to fermentative, and though only making 2 ATP per six carbon sugar, quickly overwhelms all other microoganisms by dint of sheer reproductive rate.
That there are very few S. cereviseae on the grape surface proves nothing. They are fully capable in such small numbers to outcompete the competition. Not that I’m taking sides.
I have more on this. Does anyone have any further info on Mortimer’s research and any follow up studies?

]]> By: Bench Grafts: What I’m Up To http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-459 Bench Grafts: What I’m Up To Thu, 23 Oct 2008 03:40:41 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-459 [...] over at Wine Sooth has posted an exhaustive three part series on wild wine yeasts dubbed “Yeasts Gone Wild.” He even has a scandalous pic [...] [...] over at Wine Sooth has posted an exhaustive three part series on wild wine yeasts dubbed “Yeasts Gone Wild.” He even has a scandalous pic [...]

]]> By: wine sooth » Blog Archive » Yeasts Gone Wild: Part 3. http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-449 wine sooth » Blog Archive » Yeasts Gone Wild: Part 3. Fri, 17 Oct 2008 07:06:06 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-449 [...] is the third post in a series of three that look at the idea of wild yeasts. (See the first post here and second post [...] [...] is the third post in a series of three that look at the idea of wild yeasts. (See the first post here and second post [...]

]]> By: Josh http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-443 Josh Thu, 16 Oct 2008 03:25:49 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-443 Great series Arthur! Just wanted to note that Joel conveyed to me that the yeast identified in the vineyards was distinct from those they had used in the winery in the past. I was - and am still - thrilled that Joel was kind enough to allow me to share Ravenswood's research. Really good stuff. Great series Arthur!

Just wanted to note that Joel conveyed to me that the yeast identified in the vineyards was distinct from those they had used in the winery in the past.

I was - and am still - thrilled that Joel was kind enough to allow me to share Ravenswood’s research. Really good stuff.

]]> By: Jerry D. Murray http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-441 Jerry D. Murray Thu, 16 Oct 2008 02:41:28 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-441 Arthur, I do want to go on the record as being a winemaker that employ's spontaneous fermentations. It works well for me ( in Pinot Noir ). My issue arises from critics ( I use the term loosley ) that dismiss wines because they were made from cultured yeasts. I won't second guess a winemaker that avoids spontaneous fermentations, we all have our own level of risk we are comfortable with. Arthur,

I do want to go on the record as being a winemaker that employ’s spontaneous fermentations. It works well for me ( in Pinot Noir ). My issue arises from critics ( I use the term loosley ) that dismiss wines because they were made from cultured yeasts. I won’t second guess a winemaker that avoids spontaneous fermentations, we all have our own level of risk we are comfortable with.

]]> By: wine sooth » Blog Archive » Yeasts Gone Wild: Part 2. http://www.redwinebuzz.com/winesooth/2008/10/12/yeasts-gone-wild-part-1/#comment-440 wine sooth » Blog Archive » Yeasts Gone Wild: Part 2. Wed, 15 Oct 2008 07:06:32 +0000 http://www.redwinebuzz.com/winesooth/?p=510#comment-440 [...] wine sooth searching for truth in wine « Yeasts Gone Wild: Part 1. [...] [...] wine sooth searching for truth in wine « Yeasts Gone Wild: Part 1. [...]

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