Ascorbic acid - safety note

[Transform]

Here's something I've mentioned earlier today which seems worthy of attention considering my preference for the use of ascorbic acid when brewing harmala-containing material:

Post in thread 'What is the best syrian rue recipe (without extraction)?'

Yesterday at 2:20 PM

I've been thinking. One caveat about regular use of ascorbic acid in above-normal concentrations is that one of its decomposition products is oxalic acid/oxalate. It would be wise to include a suitable amount of a calcium salt so that stray oxalate can be bound up in the form of highly insoluble calcium oxalate. This will help prevent cumulative oxalate toxicity in the case of frequent use of ascorbic acid when brewing.

An alternative, besides destroying the oxalate with hydrogen peroxide, would be to isolate the harmala alkaloids (which should also give an indication of whether the...

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[stuartroelke]

Incredible timing—last night I was looking up the effects of using ascorbic instead of citric for various teas and/or leaf extractions (primarily with fresh kratom and guayusa). Decomposition is what made me concerned. Good to know I wasn’t overthinking.

 

[Transform]

Incredible timing—last night I was looking up the effects of using ascorbic instead of citric for various teas and/or leaf extractions (primarily with fresh kratom and guayusa). Decomposition is what made me concerned. Good to know I wasn’t overthinking.

Funny. I was lying in bed last night when the thought just popped up… rue-salvia co-telepathy?

 

[murklan]

Ah! Thanks a lot! I've been using ascorbic acid for my weekly rue tea. Before I was using citric acid but I found that ascorbic didn't make me as nauseous. But I will shift back now and try to see it there are something else I can do to reduce it.
I eat plants that might already have oxalic acid so I don't need any more of that.

 

[Transform]

Ah! Thanks a lot! I've been using ascorbic acid for my weekly rue tea. Before I was using citric acid but I found that ascorbic didn't make me as nauseous. But I will shift back now and try to see it there are something else I can do to reduce it.
I eat plants that might already have oxalic acid so I don't need any more of that.

Weekly use should be fine, especially if you have an equivalent amount of calcium added at some stage of the brewing process, e.g. through the use of hard tap water. How much ascorbic acid have you been using? The maximum amount of oxalic acid produced will be roughly 50% of that amount, and can be neutralised by about 23% its weight of calcium. This would equate to 57mg of calcium carbonate per 100mg ascorbic acid, just off the top of my head - and not all (dehydro)ascorbic acid decomposes to oxalate anyhow.

Check by calculation:
C₆H₈O₆ - 2H → C₆H₆O₆ [mw = 174]
C₆H₆O₆ + 2H₂O → C₄H₈O₄ + (COOH)₂ [mw = 90]
(COOH)₂ + CaCO₃ [mw = 100] → CaC₂O₄↓ + H₂O + CO₂↑
90 mg oxalic acid resulting from 176 mg ascorbic acid gets neutralised by 100 mg calcium carbonate, so that resulting from 100 mg ascorbic gets neutralised by 100*(100/176) ≈ 56.8 mg calcium carbonate

Of course the point is not so much the neutralisation but the insolubility of calcium oxalate, which is both the main reason behind its toxicity as well as a practical solution to the issue.

 

[murklan]

Weekly use should be fine, especially if you have an equivalent amount of calcium added at some stage of the brewing process, e.g. through the use of hard tap water. How much ascorbic acid have you been using? The maximum amount of oxalic acid produced will be roughly 50% of that amount, and can be neutralised by about 23% its weight of calcium. This would equate to 57mg of calcium carbonate per 100mg ascorbic acid, just off the top of my head - and not all (dehydro)ascorbic acid decomposes to oxalate anyhow.

Seems like your top of the head is working very well
I've been using ~1g of ascorbic acid each time. I don't have any calcium carbonate right now and the water here is quite soft. But I do have some old gypsum (calcium sulfate dihydrate) from making tofu the chinese way. Might that work?
Anyhow I think I'll switch back to citric acid next time.
Thanks again!