Talk to me about Fermaid-K and yeast nutrient

[beerisyummy]

Hey there brüers -

Anyone out there a dedicated Fermaid-K user? How do you use it? Do you

• "wait until 2/3 sugar depletion" as specified or use it at a different time? or
• just dump it in the fermentor, or reconstitute in sterile water first, or boil it?

And how about yeast nutrient? With both WLN-1000 and Servomyces I think I've noticed it clumped up in the trub at the end of the boil, so I'm not sure how much good it's doing. Thoughts?

 

[Gnomebrewer]

Beer, mead or cider?
2/3 sugar depletion sounds like a mead thing.
For beer, it can go in the last 5 to 10 minutes of the boil.

 

[Terpene]

Fermaid K contains nutrients the yeast use for *cell growth*, such as ammonium and free amino acids for protein synthesis and fatty acids for cell walls.

The growth phase of yeast occurs early in fermentation, so if you're going to use nutrients, you should use them earlier, not later.

Last 5 to 10 minutes of the boil, as Gnomebrewer said, sounds like solid advice to me.

 

[mediant]

As you've noticed already, boiling will precipitate much of the nutrients with the trub. For brewing manufacturer recommends the following simple procedure: Fermaid K should be dispersed (stirred) into the wort just prior to pitching the yeast.

 

[Terpene]

You're correct about the manufacturer recommended usage.

But I think it's required to consider each of the components of Fermaid K before stating that they'll precipitate and end up in the trub.

- Ammonium is soluble. Won't precipitate.
- Free amino acids should be both soluble and stable in boiling wort.
- Thiamin is also soluble and stable at acidic pH.

My bigger concern would be adding it at pitching temp. I would not want to introduce any extraneous organism that may be in the nutrient. Even from the factory F-K is not completely free of wild yeast, but after sitting around in my brew kit for years, I wouldn't trust it at all. Perhaps adding at flameout would be reasonable.

I'd be wary of adding any yeast nutrient below pasteurization temperature, regardless of manufacturer recommendation. But that's just me.

 

[mediant]

But I think it's required to consider each of the components of Fermaid K before stating that they'll precipitate and end up in the trub.

- Ammonium is soluble. Won't precipitate.
- Free amino acids should be both soluble and stable in boiling wort.
- Thiamin is also soluble and stable at acidic pH.

Some (?) of amino acids come in form of yeast hulls, which most likely will precipitate...

My bigger concern would be adding it at pitching temp. I would not want to introduce any extraneous organism that may be in the nutrient. Even from the factory F-K is not completely free of wild yeast, but after sitting around in my brew kit for years, I wouldn't trust it at all. Perhaps adding at flameout would be reasonable.

I'd be wary of adding any yeast nutrient below pasteurization temperature, regardless of manufacturer recommendation. But that's just me.

Understandable, but please bear in mind that F-K was developed for oenology, where boiling temperatures are never reached. In fact, using it is no different from pitching dry yeast from my point of view. I guess it can be dissolved in some boiling water before adding to fermenter for additional peace of mind...

BTW, there's an explanation why staggered addition of F-K is beneficial (at least for wine fermentation): It is best to add Fermaid K™ over two additions. The first addition is made at the end of the lag phase (6 to 12 hours after yeast inoculation) and the second addition is made around 1/3 sugar depletion (the end of exponential growth and the beginning of the stationary phase). With proper rehydration and handling, the yeast cell population should be at least 4 million cells/mL at inoculation. By the time the second Fermaid K™ addition is made, this population should have grown to about 100 million cells/mL. It is critical to remember that yeast are still reproducing during the stationary phase, and to do this effectively, especially in high sugar musts, they need oxygen as well as the components of Fermaid K™, including nitrogen (for protein synthesis), sterols and fatty acids (for maintaining alcohol resistance and permease activity). In addition, the inactivated yeast cell walls in Fermaid K™ adsorb medium-chain fatty acids that are toxic to yeast, and provide nucleation sites to help keep the yeast in suspension

 

[Terpene]

Some (?) of amino acids come in form of yeast hulls, which most likely will precipitate...

Free amino acids are free amino acids, regardless of source. Sure, some other components of the yeast hulls may precipitate or may never even dissolve in the first place. But the amino acids will dissolve and should stay in solution.

Understandable, but please bear in mind that F-K was developed for oenology, where boiling temperatures are never reached.

Thanks, I didn't know that. So much to learn on this board!

It is critical to remember that yeast are still reproducing during the stationary phase, and to do this effectively, especially in high sugar musts, they need oxygen as well as the components of Fermaid K™, including nitrogen (for protein synthesis), sterols and fatty acids (for maintaining alcohol resistance and permease activity).

That sounds right, but I would note a couple things in response. In the stationary phase net cell growth is essentially zero, so any new cells would be replacing presumably dead ones. Also, as noted, new cell growth would require oxygen, so adding more FAN without an addition O2 charge might not have the intended effect, might be essentially adding unnecessary extra FAN.

I guess it can be dissolved in some boiling water before adding to fermenter for additional peace of mind...

Agreed.

 

[Terpene]

I think one important thing to remember is that FAN supports cell growth. A brewer should use that understanding, along with knowledge of the growth cycle, and apply it to the particular results the brewer is trying to achieve. With that in mind, there could be many potential use cases for yeast nutrient. There's no single correct answer, IMO.

 

[RPh_Guy]

I typically use 1g of Fermaid K in starters. I don't know whether it helps, but it makes me feel better. I never have fermentation problems.

Cheers

 

[mediant]

That sounds right, but I would note a couple things in response. In the stationary phase net cell growth is essentially zero, so any new cells would be replacing presumably dead ones. Also, as noted, new cell growth would require oxygen, so adding more FAN without an addition O2 charge might not have the intended effect, might be essentially adding unnecessary extra FAN.

Yup, not much use in regular brewing. I can see this applied to HG brewing though, like barley wine, where intermittent aeration is recommended.