Why doesn't hot charcoal glow blue?

Any black body emits radiation of all frequencies. So a hot charcoal definitely emits some blue light. It doesn't appear blue, because most of its light is red, orange, or yellow. To shift the spectrum toward perceiving the white light, you must increase the temperature to the temperature of the Sun (5,778K), but this would destroy your furnace, as we don't have materials capable of sustaining this temperature. The highest recorded melting point is 4,215K of tantalum hafnium carbide. To make charcoal blue, you would need to increase its temperature even more, which is unrealistic in any existing furnace.

Hot iron doesn't become bluish white, but only yellowish, because it melts at 1,811K. You may see bluish colors on it after it cools down. They are caused by thin layers of iron oxide reflecting light differently for different wavelengths.

Iron is supposed to glow blue-white at around 1600 degrees C. page 7.

Would carbon have that color at that temperature?

Spectral lines of iron

Spectral ines of carbon

Maybe not. Maybe those bright yellow lines would add too much. Carbon might have to be hotter.

Do we have examples of carbon heated very hot? How about a carbon arc lamp? Pass a whole lot of electricity between two pieces of carbon. Some carbon vaporizes, and the hot carbon vapor gets very bright.

Does this look bluish-white to you? Maybe it's possible, and maybe the charcoal has to be vaporized to do it. Can you find a way to get charcoal to do that by burning it with pure oxygen? I don't know. Can you get that color with solid charcoal, or would the carbon vaporize first? Carbon's sublimation point is 3642 C, so maybe.

Sorry I can't give a more definite answer.

(Here's a tip if you want to look for yourself. If you do an image search that includes "white-hot" or "blue-white-hot", be sure to set your censor. For reasons I didn't think of ahead of time, these searches produce a lot of porn.)

The glowing color of an object is based on its temperature. Wood Charcoal probably won't get hot enough to look blue. The sun is around 5500 degrees and emits all colors of em radiation. Wood charcoal will take a lot of help from the user (pumping air on the charcoal) to approach that required temperature and it will probably turn to ash before the temp is even reached. To glow with a blue color, the required temperature is probably greater than 8000 degrees.