I’m not sure I’m totally understanding this question because any coal, whether brows or lump won’t produce a lot of smoke when ashes over. Are you using wood? What coals are you using? How are you setting your vents? That may be something. If the vents are closed down to much, the fire will be starving for air and will produce an acrid, White chugging smoke.
Let’s hear some further comments and maybe some more explanation from you and see if we can’t nail it down.
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