  High-energy open beauty photoproduction probes the vacuum exchange at
distances $\sim 1/m_b$ and detects significant corrections to the BFKL
asymptotics coming from the subleading vacuum poles. We show that the interplay
of leading and subleading vacuum exchanges gives rise to the cross section
$\sigma^{b\bar b}(W)$ growing much faster than it is prescribed by the exchange
of the leading pomeron trajectory with intercept
$\alpha_{\Pom}(0)-1=\Delta_{\Pom}=0.4$. Our calculations within the color
dipole BFKL model are in agreement with the recent determination of
$\sigma^{b\bar b}(W)$ by the H1 collaboration. The comparative analysis of
diffractive photoproduction of beauty, charm and light quarks exhibits the
hierarchy of pre-asymptotic pomeron intercepts which follows the hierarchy of
corresponding hardness scales. We comment on the phenomenon of decoupling of
soft and subleading BFKL singularities at the scale of elastic
$\Upsilon(1S)$-photoproduction which results in precocious color dipole BFKL
asymptotics of the process $\gamma p \to \Upsilon p$.
