Yeast Nutrient(s): Best resource for information?

[Dolmetscher007]

I am not a chemist, but I am an extremely curious person that does not ever like to just accept things at face value. In other words, I always want to know what's in something, why is it used, is it the only way to do it, why, why, why...!?! Yup... I'm "that guy."

I don't care about actually making my own yeast nutrient as a cost-savings measure since it really isn't expensive at all. But, I DO want to make some myself, just because... yeah... making.

I cannot find a reliable resource for how to make yeast nutrient. I have read and seen a TON about feeding yeast boiled dead yeast as a yeast nutrient. And I've also read a lot about people using raisins. I understand the science behind both of those solutions, but I am interested in more chemical solutions.

I have read a lot about DAP (Diammonium Phosphate) and I know that your pretty standard "Yeast nutrient" from the LD Carlson Co. appears to just be a combination of DAP and "Food Grade Urea" (i.e. Piss!... jk). Now, both DAP and Urea are two of the main ingredients in agricultural fertilizer(!!!) so, I do not feel comfy just tossing the two powders together, and teaspoon'ing some into my hooch. Even if I am only going to be adding tiny amounts, just guessing doesn't scratch my curiosity itch.

Furthermore, I have seen other products that are marketed in a little more sophisticated way, such as Cellar Science's "Fermaid O" which claims to be an organic yeast nutrient, which I imagine means that it does not contain DAP, which is inorganic. And Wyeast makes a yeast nutrient blend that they say is a: "Proprietary blend of vitamins, minerals, inorganic nitrogen, organic nitrogen, zinc, phosphates and other trace elements." (they are obviously not fans of the Oxford comma).

So, since DAP ranges in price from <$1/lb. to >$30/lb. but seems to be the main ingredient in most yeast nutrient, along with the fact that other companies seem to be including all kinds of things in addition to, or other than, DAP... I am sufficiently baffled enough to really want to make my own, and answer all my "why's". Does anyone have a good resource on DIY yeast nutrient that really gets in there and explains what's up? Even just an online "DIY Yeast Nutrient Recipe" that isn't just about killing yeast or using raisins, would be awesome!

 

[Immocles]

I've been haphazardly researching this a bit myself recently (if drinking beer and googling can be considered 'researching') and landed on trying the boiled bread yeast the next time I try a mead. Some folks appear to swear by raisins, others say that it doesn't do a damned thing nutrient-wise, but helps with in other areas (mouthfeel, tannins). I did stumble across a page which gave a few ideas for adding fruits as a small source of nutrients.

https://denardbrewing.com/blog/post/Nutrient-fruit/

This information is definitely geared toward mead-making, however.

I'm very curious in all of this myself and I'm positive there are others on the board who have waaaaaay more knowledge and suggestions than I can give.

 

[couchsending]

99.9% of the time you don’t need anything other than additional zinc for beer fermentation.

You can buy Zinc Phosphate Monohydrate or Heptahydrate for pennies compared to what you’ll spend on yeast nutrient that is mostly filler anyways.

 

[CascadesBrewer]

99.9% of the time you don’t need anything other than additional zinc for beer fermentation.

It is odd that the White Labs one is the only one I have seen that says it contains zinc (and it sounds like Wyeast makes one that contains zinc). The info from Chris White is that zinc is only needed if you harvest yeast and are 2 or 3 generations in as the yeast in the packet have plenty of zinc. I have looked at yeast nutrient a few times and I guess not found enough compelling info to make me add another step to my brew day.

 

[Robert65]

DAP and other nitrogen compounds are the basis of yeast nutrients for wine, mead and cider, which are deficient in FAN. All beer wort has sufficient FAN; in fact, using many modern (especially American) malts, far too much. The excess not consumable by yeast will be available to feed spoiling organisms and will, through Strecker degradation, rapidly lead to transformation of lipids into the familiar, cardboardy aldehydes, the same as in oxidative staling, but even in the absence of oxidation. These nutrients are never appropriate for use in beer.

All yeast, in every generation, requires zinc for normal metabolism, protein synthesis and cell growth, and a timely and ordered fermentation. Lacking sufficient zinc in pitching wort (at least 0.1-0.15 mg/L,) growth will be retarded, fermentation will be slow and full attenuation may not be achieved, and diacetyl reduction will be incomplete. (With a proper zinc level, ales should reach full attenuation in 2-3 days and cold fermented lagers within 7.) Zinc is also important for good foam qualities in beer.

All beer worts are deficient in zinc. Even if analyses suggest that water and malt contain enough, at least 80% of it is retained in the spent grains at mashing, and most of what passes into the wort is unavailable to yeast due to chelation. Supplementation is imperative.

Servomyces provides bioavailable zinc in the form of dead yeast grown on a zinc rich medium. Wyeast nutrient also provides bioavailable zinc, as apparently does the White Labs product. Not all non-biological additives will be available to yeast; the standard chemical additive however is zinc chloride. Measuring an appropriate quantity of heptahydrate on the homebrew scale will be virtually impossible, and above the recommended range (>0.5 mg/L) it becomes toxic to yeast. Biological sources, including extractives of yeast or spent grain fermented with lactobacillus may be preferred. It is highly unlikely that bread yeast is a viable source.

For reliable information and further references, try a standard brewing textbook like Kunze or Briggs, et al.