Asked by g.law ·September 24, 2019 ·16.2k readers

What kind of vinegar

Can i use regular white vinegar to soak the lightly browned eggshells in to produce water soluble calcium

From the KNF library

From the KNF library Drafted by Claude from Office Hours and the books · Sep 2026 · 4 sources

Yes. White vinegar works for dissolving eggshells into water-soluble calcium (WCA). (Office Hours Ep. 69, 40:38)

Drake's written recipe names brown rice vinegar. (Cho's Solutions, p. 13) The KNF Demystified version says only vinegar, at ten times the shell weight and volume. (KNF Demystified, p. 40) A living vinegar with a mother is for Cleanser, not for WCA. (Office Hours Ep. 69, 40:38) The library does not say cider vinegar beats white vinegar for this job.

Toast the crushed shells on low heat until slightly brown, like a roasted marshmallow. Winnow off the membranes. (Cho's Solutions, p. 13)
Mix 1 part shells to 10 parts vinegar by weight. (Cho's Solutions, p. 13)
Dissolve for 7 days under a breathable lid. (Cho's Solutions, p. 13)
The shells stop bubbling when the reaction is done. (KNF Demystified, p. 40)

After the reaction, the solution is neutral in pH. (Pure KNF Manual, p. 51)

Sources

40:38 Office Hours Ep. 69 (Mar 2023) — Fish Amino Acid (FAA) Recipe, Vinegar Pasteurization, JMS Starches · “White vinegar works for dissolving eggshells (WCA) and burnt bone (WCP), but Cleanser should always use a living vinegar with a mother.”
p. 13 Cho's Solutions · “Eggshells will turn slightly brown (like a perfectly roasted marshmallow) when done • Winnow to remove membranes • Mix 1 part eggshells with 10 parts brown rice vinegar by weight • Dissolve for 7 days with breathable lid”
p. 51 Pure KNF Manual · “After the reaction with the vinegar, the solution is then neutral in pH.”
p. 40 KNF Demystified · “Add cooked shells to 10x of vinegar by weight and volume Allow to dissolve for several days until the eggshells stop bubbling.”