Brown Foam

[ajambura]

What is the denser brown foam that accumulates while boiling sap? What is it from? I always skim it off but I'm just curious.

[KV Sappers]

I read somewhere its a chemical reaction that occurs as the sap heats causing minerals in the sap to precipitate as solids called niter. The minerals stick to the organic compounds that make up the foam.

[ajambura]

Got it. Thank you!