Fermaid O

Fermaid O

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Fermaid O is a newer formulation of the same Fermaid K that winemakers everywhere have learned to trust their ferments to. The main difference in composition between the two, is that the Fermaid O has replaced the inorganic DAP with an organic source. In terms of how this benefits the winemaker, there are several points!


  • Organic Nitrogen is easier for your yeast to digest, resulting in a smoother, more consistent fermentation.
  • Fewer fermentation spikes means better yeast health, and the ability to ferment to its full capacity.
  • Compared to DAP, Fermaid O will result in lower heat output from the yeast, and lower levels of negative sulfur compounds.

This is a nutrient which will boost the quality of wine, regardless of process. Lower heat production, less negative flavor compounds, better overall fermentation kinetics and flavors!

To Use:
Use at a rate of 1.5g / gal of must/juice.

Like Fermaid O? Then you will love CellarScience® FermFed DAP Free Yeast Nutrient!

Community Q&A

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Browse 2 questions Browse 2 questions and 4 answers
Why did you choose this?
MoreFlavor Store
Recommended by a commercial winemaker
brian h on Feb 22, 2023
Christopher D on Feb 8, 2023
Recommended by a commercial winemaker
brian h on Feb 22, 2023
need it
Cynthia r F on Feb 10, 2023
Christopher D on Feb 8, 2023
Making mead
Joseph on Feb 6, 2023
Want to feed my yeast.
Christopher C P on Jan 25, 2023
need it, plus i've heard ferm K has DAP in it
Alexander F on Jan 13, 2023
ferment like a pro
Jerold J C on Jan 11, 2023
Want to learn brewing.
Valued C on Dec 17, 2022
To nourish my yeast during fermentation
Lori W on Dec 14, 2022
Jump start fermentation
Jerry G on Dec 9, 2022
First try to make white wine .
Minji K on Dec 2, 2022
price and previous performance
William S on Nov 24, 2022
yummy for yeast
Vincent C on Nov 24, 2022
Proven results at our winery and cidery
Mark B on Nov 8, 2022
Haven’t tried yeast nutrient in any of my meads and I wanted to see how it does.
Phil R on Oct 20, 2022
to start the process better
Samuel E A on Oct 15, 2022
Great product
Vincenzo LaValle on Oct 7, 2022
To make the juice
Raymond O on Oct 6, 2022
Nutrients are a must
Travis B on Oct 5, 2022
Healthy yeast during fermentation
Marshall C on Sep 29, 2022
it has always provided reliable fermentation
David P on Sep 29, 2022
heard it was the best
warren b on Sep 22, 2022
works well
Jim G on Sep 20, 2022
Great, more efficient nutritional source than Fermaid K. You need to pay attention to quantity used, as it's dosed differently than Ferm K.
Edward B on Sep 16, 2022
Reliable for starting fermentation
Michael L on Sep 15, 2022
Always works
Andrew Stephen H on Sep 13, 2022
Using yeast selections I have never used, both call for a nutritious must according to the spec.sheet.
Tom D on Sep 10, 2022
Seems to help with clean fermentation.
Joseph A. Wilson on Sep 6, 2022
organic nitrogen provides steady-rate fermentation; yeasts take it up and use it as required.
John Overholt on Sep 2, 2022
good nutrition
Patricia C on Aug 25, 2022
Because its the best nutrient out there
Gregg O on Aug 24, 2022
I've used this before with great results/
MICHAEL S H on Aug 24, 2022
recommended by enology professor
KUEHN C on Aug 17, 2022
Because B3 recommends using it...
Bryan I on Aug 11, 2022
Best fermentation nutrient
Damien A on Aug 10, 2022
Worked Great Last Year
David G on Aug 5, 2022
Standard choice , feed the yeast
Dean K on Aug 3, 2022
Helps balance fermentation
Dominic A on Jul 30, 2022
For mead
James M on Jul 23, 2022
To keep my yeast happy during fermentation
John H on Jul 20, 2022
My standard procedure making mead
Wanna make mead
Tanner A on Jul 14, 2022
Used before
Lloyd W Fryer J on Jul 4, 2022
Russ H on Jun 26, 2022
Recommendation from a friend
Chuck T on Jun 23, 2022
hard seltzer
David J E on Jun 17, 2022
When used properly, this product gets mead to fully ferment in about a month
Gary M on Jun 6, 2022
need it
STEEN SIGMUND on May 9, 2022
It does not contain urea.
Dennis B on May 5, 2022
Cheapest fermaid o I could find
Andrew K on May 3, 2022
need it
Cynthia r F on Feb 10, 2023
Making mead
Joseph on Feb 6, 2023
when is fermaid o introduced into the wine must?
Anthony DAmico on Oct 25, 2021
BEST ANSWER: I add fermaid o to my must once the brix level is approx. 1/3 to 1/2 of its' original brix
The dosage rage is listed as 1.5g/gal of must/juice. The Fermaid O spec sheet lists the dosage rate at 20g/hL (or about .7g/gal). Which one is correct (or better)?
Barry P Landaiche on Apr 11, 2022
BEST ANSWER: Really depends on what you need and what you are fermenting..
Comparing 1gal is quite different than a hL. It's not completely linear when scaling up in size between homebrew vs commercial. Their suggested rates are different, but so is their whole setup.

Regarding your question, depends more on what you are fermenting and how high your gravity. If I'm making a simple wine or cider, I usually add around 1.5g/gal. But I'll use less if I'm using whole fruit, maybe 1.0g/gal when I pitch yeast. I may do another nutrient addition after a couple days if there are signs of a stressed fermentation.

If doing mead or sugar wash, I'd aim for the higher nutes 1.5g/gal.

If you really want to dose appropriate, look up TOSNA. I think the site Meadmaderight has a really easy free calc to help.

4.9 / 5.0
18 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 5 out of 5
O better than K
O is harder to dissolve than K but makes you he yeast work harder and results in a better product!
September 23, 2023
over 5 years ago
Rated 5 out of 5
Looking forward to trying it
October 28, 2022
11 months ago
Response from MoreFlavor
We are so sorry to hear about your bad experience with the Fermaid. You are still within our return policy and warranty window for a damaged product. Please go to our website, scroll to the bottom of the page, and use the Return an Item form and we will set you up. Cheers!
November 4, 2022
Malcolm Lieban
Rated 5 out of 5
Robust Ferment
Used a couple of yeasts that it is claimed need nitrogen. No sulfur no stuck ferment. Seems like the yeast must’ve gotten what it needed.
October 2, 2022
1 year ago
Rated 5 out of 5
great product, works as described.
great product, works as described.Write your review here. It must be at least 20 characters long. Consider whether you would recommend this product and what you like or dislike about it.
February 23, 2022
1 year ago
Rated 5 out of 5
Best nutrients
Want your brews to ferment as well as possible? Feed your yeast the best nutrients. Fermiad-O in TOSNA3.0 will help you get there.

My only complaint is the bag is not resealable. Otherwise, great product.
February 16, 2022
1 year ago
Rated 5 out of 5
Fermaid O
I have not had any problems with off aromas during fermentation since I started using this. It keeps the yeast really happy.
January 17, 2022
over 2 years ago
Rated 5 out of 5
Hard Seltzer
I’m using Formaid O to insure a complete fermentation of sugar. It seems to be making a difference.
December 7, 2020
over 2 years ago
Rated 5 out of 5
Great product. Will buy again.
A good product for higher surgar musts to ensure a likely successful fermentation.
October 27, 2020
over 2 years ago
Rated 5 out of 5
Good product
Good product! Recommended by the pros.
June 14, 2020
over 3 years ago
Rated 5 out of 5
First time experience
I just used Fermaid O in a batch of Black Raspberry (which I grow) wine. I had a good but not foamy fermentation. Fermented down to SG 0.992. So, based on this one experience, I can recommend it, as it does it's job. Bigger tests for it as the harvest season approaches... Cheers!
August 10, 2018
over 5 years ago