Asked by chefryano ·August 23, 2019 ·17.3k readers

WCP

I’m having trouble dissolving my blackened bones in vinegar. I went for it a second time today and I didn’t get any sort of science experiment foaming eruption, just some bubbles. The first time I thought it was maybe because I used multiple vinegars, rice wine, red wine etc but this last time I stuck with distilled white and just a few bubbles. Do the bones need to go into the vinegar hot? I used beef marrow bones, roasted them, removed the marrow then barbecued in the coals till black and cracking apart.

From the KNF library

From the KNF library Drafted by Claude from Office Hours and the books · Sep 2026 · 5 sources

Drake's library says a few bubbles are normal. Cho's manual says small bubbles appear, and when the movement stops the bones are done, in about 7 days. (Cho, Recipe, p. 65) Distilled white vinegar works for burnt bone. (Office Hours Ep. 69, 40:38)

Check the char. Brown bones are under-done and grey bones are over-done, so aim for black. (KNF Demystified, p. 41)

Crush the black charcoal and combine it with 10 parts vinegar by weight. (KNF Demystified, p. 41)
Use 1 part bones to 10 parts vinegar, with a breathable lid. Stir daily for 7 days. (Cho's Solutions, p. 13)

Cho's manual lists 23 to 25°C as the optimum temperature. (Cho, Recipe, p. 64) The library does not say whether bones should go into hot vinegar.

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)”
p. 41 KNF Demystified · “If bones are brown in color, they are under-done and if they are grey in color, they are over-done.”
p. 13 Cho's Solutions · “Mix 1 part bones with 10 parts brown rice vinegar by weight”
p. 65 Cho, Recipe · “Small bubbles will appear. If there is no movement, it means that the process of solution is completed (about 7 days).”
p. 64 Cho, Recipe · “The optimum temperature ranges from 23”