As a kid we had a row of blackcurrants at the bottom of our garden and I think I aquired a taste for these wonderful fruits from an early age, I soon learnt to tell which ones where ripe for picking by sampling a few, and if they tasted good I would ask my mum for the colander to collect them in. They dont all ripen all at the same time, so we just picked them when wanted some and my mum would magically transform them into jam and small scrmmy tarts.
If you put off picking for too long thouhg, the birds will scoff the lot!.
If in doubt, you can always cheat and ask at a local PYO, Farmers rarely miss a trick! Good Luck Tbird+