Comment by steve_adams_86
6 days ago
Citric acid doesn't work. There are other effective reducing agents too, like Sodium thiosulfate and Sodium/Potassium metabisulfite that are pretty easy and affordable to get a hold of, but even if dosed perfectly I think there's a risk of the reduction byproducts remaining and causing toxicity to things like bacteria or other small organisms. If it's over dosed, it can easily kill larger organisms too.
Ascorbic acid is the only one I've found that I like to rely on. I use it for aquaria. Although my water is very clean and has virtually no chlorine in it, it does have trace chloramine, and I can't know if my municipality suddenly needs to treat the water more intensively. So, I always treat water I put in aquariums with around 250mg of ascorbic acid to be safe. The byproducts are safe for aquatic life, or in some cases even beneficial.
I can't speak to the sodium based chemicals but as a homebrewer I use potassium metabisulfite (aka campdeb tablets or k-meta) in multiple steps of the brewing process and it has an ld50 in rats of over 2g/kg. It also allows for microbial growth again about 24 hours after being applied, and usually the first step to brewing from juice is to bop it with k-meta, wait a day and then add yeast. Then the last step (if you want to sweeten the wine) is to use even more k-meta to stun the existing yeast and potassium sulfate to stabilize. Because this also depends on cultivating a select flora I feel like a similar process would yield similar results without the risk of overdose in anything we'd like to preserve.