We find that the abundance of large clusters of nucleons in neutron-rich matter at sub-nuclear density is greatly reduced by finite temperature effects when matter is close to beta-equilibrium .
Large nuclei and exotic non-spherical nuclear configurations called pasta , favored in the vicinity of the transition to uniform matter at T = 0 , dissolve at relatively low temperature .
For matter close to beta-equilibrium we find that the pasta melting temperature is T _ { m } ^ { \beta } \simeq 4 \pm 1 MeV for realistic equations of state .
The mechanism for pasta dissolution is discussed , and in general T _ { m } ^ { \beta } is shown to be sensitive to the proton fraction .
We find that coherent neutrino scattering from nuclei and pasta makes a modest contribution to the opacity under the conditions encountered in supernovae and neutron star mergers .
Implications for neutrino signals from galactic supernovae are briefly discussed .