Your stove may have burned hotter because not all denatured alcohol is created equal. The actual composition varies widely from one brand to the next. Some are almost pure ethanol with a little isopropanol, methanol, MEK, MIBK, or benzene. Others have much more of the denaturing agent. If you were burning S-L-X brand, which is what I bought at Walmart, it is 45-50% ethanol, 45-50% methanol, and 1-4% MIBK, IIRC.