A consecutive first-order chemical reaction is modeled by $A \\xrightarrow{k_1} B \\xrightarrow{k_2} C$. The concentration of the intermediate is $B(t) = A_0 \\frac{k_1}{k_2 - k_1} (e^{-k_1 t} - e^{-k_2 t})$. If $k_1 = 0.3$ min$^{-1}$ and $k_2 = 0.1$ min$^{-1}$, at what time $t_{max}$ (in minutes) does the concentration of $B$ reach its maximum?