miekal - we've noticed that black currants are indeed labor intensive.
our most productive variety (the previously discussed chernaya
lisovenko) does not all ripen at once, and they don't hang well, so
we've got to selectively pick, which takes a long time. i might be able
to pick a gallon an hour for our first couple pickings. I have noticed
though, that other varieties (in my experience titania) thus far seem to
hang better so we can let most ripen and pick the whole cluster, saving
lots of time.
also, what method are you using to make juice? are you getting
something quite concentrated? we simmer for 20 or so minutes, then
strain, which gives us a concentrate that can be diluted about 2:1. so,
we get about twice the amount of juice from that same amount of currants
- i.e. 1 gallon of currants makes 1 gallon of concentrate or 2 gallons
of juice.