Hot water only here for glass washing. Dad and I found out that with out glasses, even using a teatowel that had been used to dry something which had been washed in soapy water would destroy the head. So no soaps here.
As for a cold glass, it creates good head because the condensation and then crystalisation of water from the air when it comes into contact with the cold glass forms frost. This 'frost' creates millions of nucleation sites for bubbles - places for them to form. Thus, a good head is obtained. It is probably retained due to the fact that the carbonation level of the beer will remain fairly high because of its cold temperature in the glass.
Cheers - boingk
As for a cold glass, it creates good head because the condensation and then crystalisation of water from the air when it comes into contact with the cold glass forms frost. This 'frost' creates millions of nucleation sites for bubbles - places for them to form. Thus, a good head is obtained. It is probably retained due to the fact that the carbonation level of the beer will remain fairly high because of its cold temperature in the glass.
Cheers - boingk