Instead of necro'ing an almost ten year old thread, I thought I'd spin up a new one regarding zinc usage for healthy fermentation for anyone doing math for themselves.
Recent generally accepted sweet spot for elemental zinc seems to be 0.3 ppm into the fermenter (that is 0.3 mg zinc per 1 L wort). However, this gets convoluted a bit since you need to take into account your form of zinc (ex. heptahydrate, monohydrate, etc.). For this purpose, I'm examing the heptahydrate (because that's what I have on hand). There's 22.8% elemental Zn in ZnSO4*7H2O (heptahydrate), so the info in the OP of that other thread would actually yield about 0.114 ppm elemental zinc instead of what they thought was a 0.5 ppm target.
The OPs prep matches closely with what BSG recommends on the low end (0.5-1.0g per 10 HL => 0.5-1.0 ppm), translating to 0.114-0.228 ppm elemental zinc.
I crunched numbers for my own purposes (6.5 gal into fermenter) and what I'd need to prepare and perform:
5.0 mL x 4940 mg/L x 1L/1000mL x 22.8% ÷ 6.5 gal x 1 gal/3.8 L = 0.228 mg/L (ppm)
Obviously your preferences and targets will vary.
Recent generally accepted sweet spot for elemental zinc seems to be 0.3 ppm into the fermenter (that is 0.3 mg zinc per 1 L wort). However, this gets convoluted a bit since you need to take into account your form of zinc (ex. heptahydrate, monohydrate, etc.). For this purpose, I'm examing the heptahydrate (because that's what I have on hand). There's 22.8% elemental Zn in ZnSO4*7H2O (heptahydrate), so the info in the OP of that other thread would actually yield about 0.114 ppm elemental zinc instead of what they thought was a 0.5 ppm target.
The OPs prep matches closely with what BSG recommends on the low end (0.5-1.0g per 10 HL => 0.5-1.0 ppm), translating to 0.114-0.228 ppm elemental zinc.
I crunched numbers for my own purposes (6.5 gal into fermenter) and what I'd need to prepare and perform:
- Stock Solution: 494 mg into 100 mL water
- Working Solution: 5.0 mL of stock solution into 6.5 gal wort => 0.228 ppm
5.0 mL x 4940 mg/L x 1L/1000mL x 22.8% ÷ 6.5 gal x 1 gal/3.8 L = 0.228 mg/L (ppm)
Obviously your preferences and targets will vary.