Chris Holman, Product Support Advisor for RJS Craft Winemaking, provided us with a crash course on potassium metabisulfite and SO2 levels in RJS wine kits:
The potassium metabisulfite (KMS) additions are as follows for the following kits:
EnPrimeur Winery Series – 4.6g
Cru Select – 4.6g
Cru International – 3.6g
Grand Cru – 3.6g
Orchard Breezin’ – 3.6g
There is also between 3-4g of KMS added to the kits at packaging to prevent oxidation and microbial attack. Most commercial wines will have total SO2 levels between 100-250 ppm and free SO2 levels between 15-40 ppm, depending primarily on residual sugar and wine pH. Below are the ranges of total and free SO2 in the bottled wine for our main products.
EnPrimeur Winery Series/Cru Select/RQ –
Total SO2 = 160-180 ppm
Free SO2 =30-40 ppm
Grand Cru/Cru International/Orchard Breezin’
TotalSO2 = 140-150 ppm
FreeSO2 = 20-30 ppm
Compared to most commercial wines, RJS Craft Winemaking wine kits tend to be more toward the lower end of the spectrum in terms of SO2 levels. In Canada, government regulations state that maximum allowable levels are 300 ppm total SO2 and 50 ppm free SO2. In the United States maximum allowable levels are 350 ppm total SO2 and 60 ppm free SO2.