Originally Posted by Gaucho100K

I agree with the above.... you tip once at the end of the meal and this should cover all the serving staff, for me the sommelier is another member of the team. Its up to the restaurant to work out how this tip gets distributed, etc.

There are special exceptions as in pre-arranged wine dinners where the sommelier has to conduct an elaborate wine service, etc. - but in most generic cases I stand by my above post.