Fermaid K vs. Fermaid O

Fermaid K and Fermaid O are yeast nutrients both produced by the Canadian company LALLEMAND.

Fermaid K
A blended complex yeast nutrient that supplies diammonium phosphate (DAP), free amino acids (organic nitrogen derived from inactivated yeast), sterols, unsaturated fatty acids, magnesium sulfate, thiamin (vitamin B1), folic acid (vitamin B9), niacin (vitamin B3), biotin (vitamin B7), pantothenic acid (vitamin B5) and inactive yeast.
Fermaid K contains about 13% N. 1g/L add about 130ppm/L of YAN (Yeast Assimilable Nitrogen).

Fermaid K (Kosher)
This nutrient is a Kosher version of Fermaid K. The composition is very similar to Fermaid K except there are no supplemented vitamins such as thiamin (vitamin B1) or pantothenic acid (vitamin B5), because these vitamins cannot be Kosher certified.

Fermaid O
This product is certified organic by OMRI (Organic Materials Review Institute). It is an autolyzed yeast nutrient with a high content of organic nitrogen (amino acids). It is formulated without diammonium phosphate (DAP).
Fermaid O contains about 6.5% N. 1g/L add about 65ppm/L of YAN (Yeast Assimilable Nitrogen).

The use of these products depends on the desired end result. However, the choice should take into consideration the following:

  • Do not combine the Fermaid K or Fermaid K (Kosher) with the rehydrated yeast slurry before inoculation.
  • Yeast don’t assimilate inorganic nitrogen (DAP) in latter part of fermentation. Organic nutrients (ie autolyzed yeast) would still be assimilable and may be beneficial.
  • There is an limit of 25g/hL of Fermaid K additions due to thiamin levels. The TTB Maximum Legal Dose for thiamin hydrochloride is 0.60 mg/L (0.005 lb/1000 gal) of wine or juice. 21 CFR 184.1875

To end, remember that fermentation in honey environments have high YAN requirements and honey is a poor source of nitrogen. Depending of the fermentation part it’s impossible avoid the use of DAP to reach the desired YAN (Yeast Assimilable Nitrogen) level.