Copper addition as Copper Sulfate (dry blue powder)

Purpose

Use this calculator to calculate the amount of Copper Sulfate Pentahydrate (dry blue powder) to add.

Background

Sulfites aromas from Hydrogen Sulfide (rotten egg smell) to mercaptans (burnt match, cooked cabbage or rubber for example) can arise during fermentation due to nutrient limitations or later throughout the aging process through breakdowns of sulfur-containing amino acids. Splashing wine to eliminate sulfide aromas can encourage the formation of disulfides, which have a lower sensory threshold than sulfides (so the wine will not smell as bad as before). These disulfides can serve as a reservoir of stink from which sulfides can be re-formed under reductive conditions, bringing you back to square one.

Dealing with these unpleasant aromas early, either by adding CuSO4 or by nutrient supplements during fermentation will minimize the amount of intervention required to fix the wine. Sulfides left untreated can form disulfides which not only sound twice as bad but are not eliminated by CuSO4 treatment alone.