  Methanol and complex organic molecules have been found in cold starless
cores, where a standard warm-up scenario would not work because of the absence
of heat sources. A recent chemical model attributed the presence of methanol
and large organics to the efficient chemical desorption and a class of
neutral-neutral reactions that proceed fast at low temperatures in the gas
phase. The model calls for a high abundance of methanol ice at the edge of the
CO freeze-out zone in cold cloud cores. We performed medium resolution
spectroscopy toward 3 field stars behind the starless core L1544 at 3 $\mu$m to
constrain the methanol ice abundance and compare it with the model predictions.
One of the field stars shows a methanol-ice abundance of 11% with respect to
water ice. This is higher than the typical methanol abundance previously found
in cold cloud cores (4%), but is 4.5 times smaller than predicted. The reason
for the disagreement between the observations and the model calculations is not
yet understood.
