FAQ - Nutriments
What is YAN?
YAN stands for Yeast Assimilable Nitrogen. It is the sum of assimilable nitrogen from ammonium ions and the assimilable Free Amino Nitrogen (FAN) present in the juice/must. Low levels of YAN are associated with the production of undesirable sulfide compounds. Recommended levels range from 250 ppm-350 ppm or higher depending on the initial Brix level.
Are Fermaid K and Superfood the same?
No. While both are yeast nutrients, each is a proprietary blend from two different manufacturers. While similar in nutrient content, Fermaid K can be added at smaller rates to achieve the same effect as Superfood. In fact, the recommended dose of Superfood is twice that of Fermaid K!
Why should I use Go-Ferm?
Go-Ferm immediately gives your desired yeast a leg up over other organisms during fermentation. Go-Ferm is added to the rehydration water of the selected active dried yeast. A "sponge effect" allows the yeast to soak up the nutrients as they soak up the water. Micronutrients are more bioavailable to the yeast, which encourages a strong and smooth fermentation.
When should I add Fermaid K? How much should I use?
Fermaid K is best added at 1/3 of sugar depletion at a rate of 2 lb/1000 gal. Fermaid K should be hydrated before adding to an active fermentation to avoid CO2 release and overflowing of tanks or barrels.
Should I use Diammonium Phosphate(DAP)? When should I add it?
DAP should be used when YANC is below 125 mg N/L. Fermaid K contains some DAP, but for very low Nitrogen content must, DAP is recommended to bring YANC to above 150 mg N/L. Each 2 lb/1000 gal (25 g/hL) addition yields 50 mg N/L inorganic (ammonium) nitrogen.
How do I test for nitrogen levels in my juice/must?
Levels can be tested through formol titration or the NOPA method. Inorganic nitrogen can be determined by using an ammonia probe.
I have an organic wine program. Which yeast nutrients can I use?
What is the difference between Fermaid K and SIY33?
SIY33 is a whole yeast cell powder providing amino nitrogen and B vitamins. Fermaid K is a blended complex yeast nutrient containing Magnesium Sulfate, Inactive Yeast, Thiamine, Folic Acid, Niacin, Biotin, Calcium Pantothenate and DAP.
When should I use yeast hulls?
Use yeast hulls to fine out toxins in the case of sluggish/stuck fermentation, to increase the surface area of clarified juice, and to supplement survival factors such as sterols.
Which nutrients are considered kosher?
The only nutrient that conforms and is documented as Kosher is Fermaid K (Kosher).
How much nutritional value does Opti-Red add to the juice/must?
Opti-RED is basically a highly specific form of autolyzed yeast. There is some benefit derived from this organic nitrogen source, but the use of Opti-RED should not preclude the use of other nutrients like Fermaid K, Go-Ferm or Go-Ferm Protect.
Why are pantothenate and magnesium sulfate important to yeast cells?
Pantothenate helps to keep open important metabolic pathways that dramatically reduce the production of H2S. Magnesium improves yeast alcohol tolerance.
Do different yeast strains require more nutrients than others?
Yes. Each strain has distinct fermentation kinetics. One strain may require less of one nutrient compared to another strain. Do your research. See the individual product descriptions to help determine your yeasts' specific needs.
Is nutrient addition timing important? Why?
Yes. Yeast metabolize nutrients at different times throughout fermentation. Dosing nutrients at the most optimal moments can enhance yeast performance. As fermentation progresses and the ethanol level rises, yeast becomes less and less able to assimilate nutrients. For this reason, each nutrient has been created for specific addition times. For example, GoFerm has been designed to add during rehydration. Other nutrients like Fermaid K are added at one-third sugar depletion and never into the rehydration water.