Rehydration nutrient
Go-Ferm, inactivated-yeast rehydration protectant
Primes dry yeast with micronutrients before it is pitched.
Typical dose
Per the product sheet, stirred into the rehydration water, not the must.
When to add it
During yeast rehydration, before pitching.
In practice
Feeds micronutrients and sterols to the yeast while it rehydrates, so the cells that reach the must are robust rather than already stressed. It goes into the rehydration water; adding it to the must instead wastes it. A strong pitch prevents more trouble than any mid-ferment rescue fixes.
Linked faults are the ones this addition either treats or, used wrongly, causes. The fault page says which, and whether it can be undone.
Others in nutrients and enzymes
Diammonium phosphate
Inorganic nitrogen for the yeast, the direct fix for a starved ferment.
Complex yeast nutrient
Nitrogen plus the amino acids, vitamins and sterols the yeast also needs.
Thiamine
A micronutrient that helps a ferment finish and lowers SO2 binding.
Yeast hulls
Detoxify a stuck ferment and give the yeast a surface to work from.
Pectic enzyme
Breaks down pectin to clear haze and free juice and colour.
Glucanase
Breaks down Botrytis glucans and speeds lees ageing and filtration.
Beta-glucosidase
Frees the bound aroma compounds locked up in aromatic white grapes.