No.You should cool the nitrating mixture itself before starting the reaction.
...The bicarbonate is used to neutralise any acidic residues in the sample, for, upon drying, they would else digest the gun cotton, making it a waste, or in the same process, generate enough heat to detonate it.
No matter how much one tries to cleanse the NC, one can never get rid of some trace acids, which could again as said before lead to explosions, etc.by some reacions, unknown to me at the moment.
Thus it is wise to store your NC in distilled water....And wise to not store it at all:).