Fermaid O Organic Yeast Nutrient | 12 g & 120 g
Fermaid O Yeast Nutrient for Mead, Wine, Cider, and Beer
Fermaid O is a DAP-free yeast autolysate nutrient from Lallemand used to support fermentation nutrition in mead, wine, cider, fruit wine, and some beer fermentations. Scott Labs describes Fermaid O as a yeast assimilable nitrogen (YAN) source that supplies organic nitrogen in the form of amino acids, along with small peptides, vitamins, and minerals.
Unlike nutrients based on diammonium phosphate (DAP), Fermaid O does not supply ammonia salts. Scott Labs lists Fermaid O as OMRI Listed, but the practical brewing reason to choose it is the organic-nitrogen format: it fits DAP-free nutrient schedules, staggered additions, and fermentations where yeast nutrition needs to be managed carefully.
How much Fermaid O should I use?
Scott Labs lists Fermaid O at 10-40 g/hL, which is about 0.38-1.5 g per gallon. Their technical sheet also lists a common split addition of 20 g/hL near the start of alcoholic fermentation and 20 g/hL around the 1/4 to 1/3 fermentation point.
For mead, use your recipe, nutrient calculator, or staggered nutrient addition plan as the final guide. Fermaid O is often added in split doses so the yeast receive nutrition as fermentation is underway rather than all at once.
When to add Fermaid O
Scott Labs recommends adding Fermaid O around a 2-3 °Brix drop and/or near 1/3 sugar depletion. Suspend it in water, juice, or must and mix well before adding. During active fermentation, add slowly and leave headspace because dry nutrient additions can trigger CO2 release and foaming.
Best uses
- Traditional, session, and fruit meads
- Red, white, rose, and fruit wine fermentations
- Hard cider and perry
- DAP-free or organic-nitrogen nutrient schedules
- Beer or mixed-fermentation projects where organic yeast nutrition is useful
Storage and handling
Store Fermaid O tightly sealed in a cool, dry place. Keep it dry once opened and follow the dated expiration on the package.
Related fermentation nutrients
For yeast rehydration, pair your nutrient plan with Go-Ferm Protect. For a DAP-containing nutrient option, see Fermaid K. For broader fermentation support, browse our yeast health and temperature control collection or read our mead yeast selection guide.