where are the black lesbian clubs in san francisco?

are there many black lesbian clubs in san francisco? preferrably in the castro area? or is that mostly white gay males?

i was in the castro last week and was caught off guard because i expected white gay men again but there were a lot of straight white people having dinner and drinking outside. I might be going back to the castro later this week and im wondering is where can i go to find black lesbians? It doesnt have to be all blacks, i just want there to be a fair pick of lovely black ladies. nothing against other races-- im open to all-- i just have a weakness for the brownsugar.