What happens to sugar when it is charred?

Sugar on heating with concentrated sulphuric acid is converted to a charred mass. 
$$\begin{gathered} With con H_{2}S{O}_4, the dehydration of sugar occur and the products are carbon and water \\ {C}_{12}{H}_{22}{O}_{11} \stackrel{Con H_{2}S{O}_4}{\to } 12 C + 11 H_{2}O \end{gathered}$$
so the sugar is converted to black coloured carbon.