Perhaps a dumb question, but:
Is it really necessary to pre-heat the milk you add to a roux to make bechamel? I missed this detail when I first learned to make it and haven't really bothered since. Does heating the liquid you add really make a difference (flavor or texture-wise)? I can see how not doing so could lengthen the time bringing the sauce back to a simmer. But...so?
Thanks for your ideas.