Why is the addition of methanol during the prepartion of the liquid crystal cholesteryl benzoate necesary Here's one way to prepare cholesteryl benzoate crystals:

Step 1 Dissolve 1.0 g of cholesterol in 3 cm3
 of pyridine in a conical flask.

Step 2 Add 0.40 cm3
 of benzoyl chloride.

Step 3 Heat the mixture on a steam bath for about 10 minutes.

Step 4 Cool the mixture, and add 15 cm3
 of methanol.

Step 5 Collect the solid cholesteryl benzoate by suction filtration. Rinse the flask and the crude crystals with a little cold methanol.

Step 6 Recrystallize the cholesteryl benzoate using ethyl ethanoate as the solvent.

The methanol is said to be added to react with the benzoyl chloride. Why is this required? 

Usually, in a preparation such as that of 1-bromobutane, some substance such as sodium carbonate is added in order to allow for separation of the aqueous substances from the organic layer. That makes sense. However, in the case of the above preparation, by adding methanol the substances within the conical flask go from benzoyl chloride, pyridine and cholesteryl benzoate to HCl, pyridine, methyl benzoate and cholesteryl benzoate. What's the point? Either way, both mixtures are going to eventually be separated from the cholesteryl benzoate by suction filtration.
Pyridinium hydrochloride and methyl benzoate are both soluble in methanol and thus will be washed through the filter leaving behind clean cholesteryl benzoate. If you don't use the methanol the solid you produce will be impure and sticky; the methyl benzoate and pyridinium hydrochloride will not pass through the filter but will bind to the product crystals.. Methanol also removes any excess of benzoyl chloride by reacting with it.