Anyone Interested in Working With Brewers Yeast?

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Avery Ashley

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Mar 17, 2013, 2:26:14 PM3/17/13
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I attempt brewing every now and then just because it's an interesting process and its always fun to work with something you can consume.
I don't know much about it, so I'm no pro. But I've been trying to think of a long term project and I though maybe engineering/selecting yeast for increased alcohol content and better ethanol to methanol ratios would be a doable, as well as rewarding process. In the end I'd like to end up with a strain that yielded a more potent, but also safer (due to less methanol) brew. 
The first thing I would focus on is (selecting?) for increased alcohol resistance, so that the yeast can stay alive and ferment longer leading to a higher alcohol content. Next I would work on the particulars of the alcohol produced. 

Anyone have any advice for a project like this? I suppose the first thing to do would be to find a yeast strain to begin with, does anyone know a good place to look?
Also, would anyone be interested in a long distance collaboration?

Daniel C.

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Mar 17, 2013, 2:45:22 PM3/17/13
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Avery,

I suppose you don't want to just buy champagne yeast? Also if you
want advice on the brewing project itself I can certainly help.

-Dan
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Avery Ashley

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Mar 17, 2013, 2:57:57 PM3/17/13
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Champagne yeast looks like a good place to start, but I'd like to try and improve upon it. 
Honestly, my end goal would be a safe and efficient yeast strain to make mash intended for distillation.
Yes, it's illegal, but there's a whole community of people who are going to do it anyway, and my mother's side of the family is among them. 
I figured if I could somehow bring methanol production to a minimum than it would greatly reduce the risk of home distillation.
I don't really understand the specifics that determine which form of alcohol is produced and in what quantity during fermentation, but it seems like an interesting area of research.

Just to be clear though, I don't intend to do anything illegal myself. I haven't ever, and don't intend to try out home distillation. I'd just like to experiment and see if there's a way to make it safer through changing the yeast involved. 

Daniel C.

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Mar 17, 2013, 3:05:14 PM3/17/13
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On Sun, Mar 17, 2013 at 2:57 PM, Avery Ashley
<avery...@rams.sccnc.edu> wrote:
> I figured if I could somehow bring methanol production to a minimum than it
> would greatly reduce the risk of home distillation.

You might want to pick up champagne yeast and work on changing the
alcohol that's produced rather than trying to get a higher alcohol
content out of it. I don't know what the physical/chemical limits on
cell integrity in an alcohol solution are, but I think champagne yeast
is bumping up against it.

-Dan

Avery Ashley

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Mar 17, 2013, 3:15:47 PM3/17/13
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Cool, thanks. 
Know of any resources I can check out to learn a bit more about the processes that determine the methanol to ethanol ratio of alcohol produced?

Daniel C.

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Mar 17, 2013, 3:25:58 PM3/17/13
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This thread looks like it has some good information:

http://www.homebrewtalk.com/f14/methanol-ethanol-203153/

apparently one of the primary factors is how stressed the yeast cells
are during fermentation - and higher alcohol content creates stress,
leading to higher levels of methanol.

Mega

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Mar 17, 2013, 3:54:34 PM3/17/13
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I heard form our famous beer-professor, that Ethanol blocks the receptors for methanol. 

So basically, it prevents Methanol from damaging your body. 


(If one has a methanol poisoning, they inject him pure ethanol as a cure)

Cathal Garvey (Phone)

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Mar 17, 2013, 4:52:53 PM3/17/13
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Well, there are better treatments available to hospitals, likely inhibitors of alcohol dehydrogenase, but yes: if you get methanol poisoning far from a hospital you can keep the enzyme busy with its preferred substrate, ethanol.

As to methanol reduction, fermentation conditions have a lot to do with it. Marc of hackteria has done fermentation workshops covering this and more, I think?

One avenue is to look at the immediate fermentation precursor of ethanol, and identify the equivalent for methanol. I suspect they are made by the same enzymes/processes, so perhaps methods to simply reduce the precursor will reduce the product, namely methanol?
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Daniel C.

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Mar 17, 2013, 5:13:44 PM3/17/13
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On Sun, Mar 17, 2013 at 3:54 PM, Mega <masters...@gmail.com> wrote:
> I heard form our famous beer-professor, that Ethanol blocks the receptors
> for methanol.

Normally I wouldn't respond, but since this is a biology-related list
I feel like it's best to be precise.

It's not actually the alcohol that kills you if you drink methanol
(well, unless you consume so much so quickly that all your cells
lyse... but that would be a challenge.) What kills you is the
metabolic byproducts of it. Since both methanol and ethanol are
broken down by the same enzymes, an injection of straight ethanol
would mean that your body is now spending its time breaking down both
alcohols instead of just methanol and producing proportionally less
methanol byproduct per hour.

-Dan

Daniel C.

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Mar 17, 2013, 5:16:46 PM3/17/13
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On Sun, Mar 17, 2013 at 4:52 PM, Cathal Garvey (Phone)
<cathal...@cathalgarvey.me> wrote:
> One avenue is to look at the immediate fermentation precursor of ethanol,
> and identify the equivalent for methanol. I suspect they are made by the
> same enzymes/processes, so perhaps methods to simply reduce the precursor
> will reduce the product, namely methanol?

One thing we could try is creating solutions of different sugars and
seeing what alcohol profiles they produce when fermented.

-Dan

chris 0

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Mar 17, 2013, 6:28:56 PM3/17/13
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If you're looking for very high alcohol ~25%
have a look at the wlp099 yeast - http://www.whitelabs.com/beer/strains_wlp099.html

You need oxygenation for such a yeast mind to get the full potential.

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Daniel C.

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Mar 17, 2013, 6:46:56 PM3/17/13
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On Sun, Mar 17, 2013 at 6:28 PM, chris 0 <viscous...@gmail.com> wrote:
> If you're looking for very high alcohol ~25%
> have a look at the wlp099 yeast -
> http://www.whitelabs.com/beer/strains_wlp099.html
>
> You need oxygenation for such a yeast mind to get the full potential.

All wort has to be oxygenated before you pitch the yeast. Typically
all that's required is shaking the carboy well when it's half full.
With a wort that's this high gravity, though, you'll need an actual
oxygenation stone (basically an aquarium stone that you hook up to an
O2 bottle) and you'll have to repeat the process daily. (Higher
gravity worts dissolve oxygen less readily.)

You'd also need high control over the fermentation temperature, which
can be accomplished with a mini-fridge and a temperature monitor /
power controller doodad. You'd probably want something like that
anyway, because fermentation temperature will likely have a big impact
on the alcohol profile you get with any yeast.

Also note that with any fermentation you'll want to add yeast nutrient
- and the higher gravity your wort is, the more nutrient you'll want
to add.

If you're doing this in the Boston area, Avery, I'd be interested in
being a part of it.

-Dan

Ravasz

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Mar 17, 2013, 6:52:35 PM3/17/13
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Hi,

In my country, home distillation is legal. And it is very simple to avoid methanol poisoning: the distilled product has to be collected in fractions. The first fractions that come out of the distillery will contain methanol and the bad stuff. The middle ones have ethanol and most of the fruity aromas, and the last ones have propanol and above. You just measure each fractions, and throw away the bad ones.

Apart from that, creating better yeast is unquestionably an excellent project. I've heard the the iGEM team of the Munich Technical University experimented with adding flavors to yeast products. Check it out here: http://2012.igem.org/Team:TU_Munich

Cathal Garvey

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Mar 17, 2013, 7:51:17 PM3/17/13
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What does oxygenation achieve? I thought yeast forewent the use of
oxygen in favour of rapid fermentation (to kill the competition!)?

Is "aeration" more important, as it might allow evaporation of other
volatile waste products?

On 03/17/2013 10:28 PM, chris 0 wrote:


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Daniel C.

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Mar 17, 2013, 8:25:18 PM3/17/13
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On Sun, Mar 17, 2013 at 7:51 PM, Cathal Garvey
<cathal...@cathalgarvey.me> wrote:
> What does oxygenation achieve? I thought yeast forewent the use of
> oxygen in favour of rapid fermentation (to kill the competition!)?
>
> Is "aeration" more important, as it might allow evaporation of other
> volatile waste products?

Yeast require oxygen to multiply. When you pitch you usually get a
couple billion yeast cells, which is substantial but not enough to
really get the job done. So they spend the first bit of time (more or
less depending on several factors) primarily reproducing. After the
"lag" phase, fermentation starts and the rest of the process is
basically anaerobic. Introduction of oxygen later in the process can
actually harm your beer, making it taste like wet cardboard or other
unsavory things. That's not such a big deal in this case since
nobody's going to be drinking the product, but it probably changes the
alcohol profile too.

I'm not sure what distinction you're making between aeration and
oxygenation. Most people oxygenate just by shaking the carboy, or
using a whisk to whip some air into the wort, or what have you, which
I would also describe as aeration. It's only the really hardcore that
get O2 stones or drill attachments.

-Dan

Patrik D'haeseleer

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Mar 18, 2013, 3:07:26 AM3/18/13
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Brewers have been optimizing alcohol production in brewers yeast for centuries. There's commercial high alcohol / fast fermenting yeast such as turbo yeast that you can easily buy. They won't necessarily make the best tasting brew though.

The risk of methanol production during ordinary fermentation are hugely overblown. The reason people used go blind from moonshine is *not* because of the miniscule amount of methanol produced during fermentation, but rather because some unscrupulous moonshiners used to mix in antifreeze or cheap store bought methanol into their product!

Patrik

Eugen Leitl

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Mar 18, 2013, 5:31:57 AM3/18/13
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On Sun, Mar 17, 2013 at 08:52:53PM +0000, Cathal Garvey (Phone) wrote:
> Well, there are better treatments available to hospitals, likely inhibitors of alcohol dehydrogenase, but yes: if you get methanol poisoning far from a hospital you can keep the enzyme busy with its preferred substrate, ethanol.

Apart from canonical ethanol drip IV (or downing a better
part of a bottle of vodka, and keep yourself titrated to
the staggering drunk level if there's a delay until you
emergency services arrive) there's also http://en.wikipedia.org/wiki/Fomepizole
and hemodialysis.
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Eugen Leitl

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Mar 18, 2013, 6:24:57 AM3/18/13
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On Sun, Mar 17, 2013 at 10:28:56PM +0000, chris 0 wrote:
> If you're looking for very high alcohol ~25%
> have a look at the wlp099 yeast -
> http://www.whitelabs.com/beer/strains_wlp099.html
>
> You need oxygenation for such a yeast mind to get the full potential.

http://en.wikipedia.org/wiki/Aspergillus_oryzae does 18-25% EtOH.

Ben Hunt

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Mar 21, 2013, 3:45:10 PM3/21/13
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As a commercial distiller I can tell you that the methanol is a bogeyman. We are required by law to not have any in the wash, and we have to get tested regularly.

The methanol myth comes from half-educated distillers that think they can distill the methanol out of denatured alcohol. In reality methanol and ethanol form an azeotrope so although you can get the stinky ketones off and a good amount of methanol, it's not possible to get enough out so it's not poisonous. All you do is make the poison taste better.

Distillers yeast is a sadly untouched area of yeast manufacture. Most of the good ones keep them to themselves and there isn't a good enough market for home distillers or even microdistilleries to get people generating strains and selling them.

two projects I always thought about doing

-a yeast that made enough amylase to break down corn or rice starches: bourbon w/o a mash, barley, or enzymes.

-gfp yeast for glow in a black light beer

Daniel C.

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Mar 21, 2013, 3:48:16 PM3/21/13
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On Thu, Mar 21, 2013 at 3:45 PM, Ben Hunt <ben.g...@gmail.com> wrote:
> two projects I always thought about doing
>
> -a yeast that made enough amylase to break down corn or rice starches:
> bourbon w/o a mash, barley, or enzymes.

I was under the impression that no yeast can break down complex
starches - which is why you have to malt barley (the enzymes in barley
break down the starches) before you can brew with it.

Couldn't you do the same thing with corn? Or just use GM sweet corn
that lacks the gene to turn sugars into starch?

-Dan

Ben Hunt

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Mar 21, 2013, 3:57:29 PM3/21/13
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Yeast can't do it, that is correct, you have to malt and mash some amount of barley or else add enzymes to break down corn. There are fungi that are happy to break down starches though, like koji (Aspergillus oryzae) which is used in making sake, and has had a genome out since 2005.

Daniel C.

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Mar 21, 2013, 4:05:54 PM3/21/13
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On Thu, Mar 21, 2013 at 3:57 PM, Ben Hunt <ben.g...@gmail.com> wrote:
> Yeast can't do it, that is correct, you have to malt and mash some amount of
> barley or else add enzymes to break down corn. There are fungi that are
> happy to break down starches though, like koji (Aspergillus oryzae) which is
> used in making sake, and has had a genome out since 2005.

So when you say "bourbon without a mash, barley or enzymes" - is the
mash a process where you partially sprout and then roast the corn?

-Dan

leaking pen

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Mar 21, 2013, 4:32:30 PM3/21/13
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First off, don't brew with Brewer's yeast. It's named after a person, not brewing, and is for baking.  Secondly, there are literally hundreds if not thousands of yeast strains that have had just that done, some hundreds of years old.  When it comes to more recent, lab created strains, Red Star has been doing a lot of that. 3rd, you get a small amount of methanol with fruit brews like wine, but from beer or grain, you really don't, and the amount you get really only matters if you're DISTILLING. 

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Cathal Garvey

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Mar 21, 2013, 4:39:58 PM3/21/13
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The azeotrope formed by methanol and ethanol is the reason that
methanol, a highly toxic compound, is used to "denature" ethanol for
tax-free sale. It's exceptionally hard to remove from the ethanol, so
it's legally assumed to be practically impossible; you'd buy taxed
ethanol for cheaper than you would do it DIY.

So yea, don't try to distil methylated alcohols and drink the results. :)

I still think a metabolomic approach might be really useful; try to
target the precursors of methanol, either by knocking out an enzyme
needed to make them (hoping thereby not to kill the cell) or by adding
a new enzyme to convert the precursor to something that won't get
fermented to methanol.

And yes, this isn't really necessary if you know what you're doing and
avoid fruit, but wouldn't it be nice to *not* have to know what you're
doing and still make nonlethal fruit wine? :)
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Nathan McCorkle

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Mar 22, 2013, 3:40:52 AM3/22/13
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Clearly the solution is to simply engineer a mammalian integration
plasmid with a toxin-cleanup gene (system)
-Nathan

Ben Hunt

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Mar 22, 2013, 7:43:08 PM3/22/13
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Dan,

The mash is the process where you run those enzymes as hard as you can by heating the mixture of grains up to around 150 F and keeping it there for an hour or so. You then sparge, which involves pouring hot water through the grain to wash the sugars out. 

What you are talking about is malting, which can be done with corn, although modern barley has much more enzymes in it; enough to, for example, saccharify the corn starches as well as the barley starches in an 80% corn / 20 % malted barley mix. The enzymes formed by malting are supposed to be used by the seedling plant to slowly grow using the starches stored in the grain. By heating them up you force them to break it all down right now, instead of in the regulated way that the plant requires to grow correctly over a week or so.

If you have a yeast strain that generates its own amylase, then you get to skip this step, although there are some problems of scale: you might put ten pounds of grain into a five gallon brew, it will be hard to get more than a few ounces of yeast cells. Even if you succeed in generating a few pounds of yeast, that might throw the flavor off pretty hard.

On the other hand, one thing that is nice about an experimental yeast strain that creates its own amylase is that you have a built in selection protocol: if the yeast doesn't break down the starch, it doesn't eat. You won't have to fool around w antibiotics, which is good if you want to drink it.

Mega [Andreas Stuermer]

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Oct 5, 2014, 5:08:20 AM10/5/14
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Reviving this old thread with new research: 

http://www.the-scientist.com/?articles.view/articleNo/41142/title/Modified-Yeast-Tolerate-Alcohol--Heat/

Two research groups modified yeast to be more resistant to ethanol (by overexpressing potassium transporters) and 40°C heat (by some kind of control switch protein). Higher temperatures probably won't be easy because many metabolic proteins would denature. Probably you'd have to take entire metabolic pathways from extremophiles. Is it still a yeast then? :D 

Frantisek Algoldor Apfelbeck

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Oct 11, 2014, 7:25:42 AM10/11/14
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Thanks for the link to the research Andreas! I'll have a more detailed look on it within week or so hoping to come back to discuss it bit more lately.

I've been doing a master research project in Ireland on production of bioethanol, our focus was breaking down the complex sugars (cellulose, hemicellose etc.) by fungus first and fermenting the fermentable sugars later on with yeasts and bacterias to get ethanol. What I would like to check is if there is more I would say "direction" towards using multiple species of microbes during the fermentaion or if there are trying to create the "super bug" as is the link which you shared I guess about. I remember that around 2007 or so there were few groups which were trying to use multiple microbes however main stream was to create "perfect bug". I prefere the combination of microbes, it is more natural to my opinion and more stable - if the "equilibrium" is reached.

Thanks,

Sincerely from Jeju,

Frantisek
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