When I burn wood, paper, or other plant matter, where there is a flame, there generally isn't too much smoke, but it I blow the fire out, smoke starts billowing up. It billows thicker and thicker as the material gets hotter, and suddenly a flame springs up. At the same moment, the smoke dissipates quickly.
I've also noticed this in wood stoves. Overnight, the fire dies down and there are no flames, only some red coals. After I pile more wood on, it begins to smoke. After a time, there is a huge amount of smoke coming up, with no flames. Wait a little longer, or blow the coals, and flames will appear, and the smoke will mostly disappear.
Why does this happen?
Are the visible flames really just glowing soot, as described here? Because I don't see why glowing soot and non-glowing soot would make a difference in smoke production. Is that claim false?