Home made yeast nutrient?

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Antti

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Has anyone made themselves an easy yeast nutrient?

Long text ahead, bear with me:

My wife makes sourdough bread, which is done without yeast.

She grows it somehow by feeding flour and water to the dough.

For some reason it "overgrows" and you end up with that excess "not -yet-dough".

I was wondering if that excess would be baked really crunchy in the oven, pulverised and vacuum packed.

Could that be used as yeast nutrient?
 
it used to be said that expired yeast when boiled makes a good yeast nutrient but that may be one of the old homebrew tales. just like raisins provided nutrients thats also nonsense i think
I believe that yeast extract is a primary ingredient of some commercial yeast nutrient products. Raisins do contain things that yeast need, but in reality it is not practical to add enough raisins to a homemade yeast nutrient to do any good.
 
Servomyces, for example, is primarily killed yeast. This is from the White Labs site:

"Servomyces is a natural zinc enriched single-strain brewing yeast (from the prestigious Hefebank Weihenstephan) that is used as a biological yeast nutrient. Servomyces enables any yeast strain's ability to incorporate essential nutrients into its cellular structure while providing a high concentration of zinc that is essential for healthy alcoholic fermentation."

Cheers!
 
The more I learn about it, the more I think zinc is the key. And now that I've been adding actual zinc to my repitches for close to a year, it looks like the data is backing that up.

As day_trippr rightly noted, dead yeast is good yeast food. It's not a raisins/olive oil fad. If you think about how yeast used to be handled pre-biochemistry, it makes sense and it worked for a very long time.

The next thing that I'm thinking about doing is figuring out how to denature and keep all that yeast that I dump down the garbage disposal. Sure, yeast nutrient is often called "cheap insurance," but I'll posit that free insurance is even better.
 
The more I learn about it, the more I think zinc is the key. And now that I've been adding actual zinc to my repitches for close to a year, it looks like the data is backing that up.

As day_trippr rightly noted, dead yeast is good yeast food. It's not a raisins/olive oil fad. If you think about how yeast used to be handled pre-biochemistry, it makes sense and it worked for a very long time.

The next thing that I'm thinking about doing is figuring out how to denature and keep all that yeast that I dump down the garbage disposal. Sure, yeast nutrient is often called "cheap insurance," but I'll posit that free insurance is even better.

You are right about the zinc. According to the most recent issue of BYO, it isn’t the dried yeast that is a good yeast food, it’s the zinc they add to the yeast in the Servomyces that allows them to get around the Reinheitsgebot:

“Servomyces is another convenient way to add zinc to wort. Like many biologically produced products used in German brewing, Servomyces allows German brewers to be Reinheitsgebot-compliant and to deliver the yeast dose that helps fermentation (direct addition of zinc from zinc sulfate and zinc chloride is not permitted by the Reinheitsgebot). Servomyces is made by growing yeast cells in an enriched media. Zinc and other trace minerals are brought into the cell, the cells are dried, packaged like other dried yeast, and added to the wort during the last 10 minutes of the boil to kill the yeast cells.”

Now as for the raisin water, I just happened to be reading about sourdough cultures and this reference had caught my eye because I hadn’t heard about the raisin thing:

“The growth of yeast and bacteria depend on three key factors: availability of nutrients, acidity, and temperature. Because growth can happen exceptionally fast, species and strains that aren’t adapted to a specific diet (like flour) can quickly be overwhelmed and die out. This is precisely why the inoculants, such as raisin water, that some bakers use to jump-start their levain don’t make a difference. (We think flour, which is chock-full of microbes, and water work just fine.)”

Sourdough cultures have evolved to do well in flour while our beer yeasts have evolved to thrive in wort. Not sure if zinc is needed for bread yeast, but the zinc does seem to be key for fermenting beer.
 
Zinc is key for fermenting beer because wort already has everything else the yeast need. But mead and cider are another story and OP didn't say what he wants to make nutrient for.
 
Well, for now just for beer yeast.
Although they must be quite similar to each other?

Intriguing would be to make a test to compare different yeast nutrients...
 
Well, for now just for beer yeast.
Although they must be quite similar to each other?

Intriguing would be to make a test to compare different yeast nutrients...

The BYO article I mentioned had this to say about wine yeast nutrients:

"Although brewers can use zinc-free wine nutrients for brewing, nutrient blends produced for brewing applications always contain zinc. Wine nutrient blends, however, do not contain zinc because zinc is not a TTB-approved nutrient, though there have been petitions to permit its use for wine. The practical point is to read labels to better understand what is being added because all beers benefit from zinc. Blends containing DAP, yeast extract/yeast hulls/yeast cells, and minerals translate to blends with inorganic nitrogen, organic nitrogen, and zinc, plus some other bits and bobs."

I have an old bottle of yeast nutrient that I have been adding to yeast starters (when I remember) but I think it was intended for wine, so I need to find a better yeast nutrient for my beer starters.
 
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