The darker the better. But at the same time a super ripe boysenberry will almost turn to juice right in your hands. Any berries in the purple to black color range will be good eating:

Funny. Went through this same exercise with boysenberries during the last 2 weeks. Mine had to be dark purple to almost black before they had that flavor explosion but, as mentioned above, they rarely detached without a mess. Overall, if you can wait until they are ready, they are quite tasty although that seemed like forever when I was waiting for them.

Again, color is not the best indicator of a completely ripe caneberry, it is either the loss of glossy surface (black berries), or the slight separation of the berry from the stem, making it very easy to bend (not pull) off the plant when picking. The nose of ripe blackberries will be filled out and the druplets there nearly the size of those at the stem end.

Red and black raspberries are different in that you pull them rather than bend them off (because they are roundish and need to be separated from the pith). For those they should pull off very easily with little or no resistance.

The normal urge is to grab once a dark color shade is reached, especially for new crops/plantings. Once years have passed and the crop becomes large, waiting for a few berries to fall on the ground is a good indication that many fully ripe berries are on the plants. Then harvest every three days to minimize berries on the ground.

larry_gene are you speaking from experience with boysenberries? They don't fall on the ground here. The druplets seem to just wither away from the tip to the base if left on too long. It's not uncommon to see the last four or five druplets still connected to the base.

No, I was speaking from experience with caneberries in general. The place I uPicked boysens last year had fallen berries on the ground.

Are you saying only boysens refuse to fall? I can see where smaller-than-average blackberries that fully ripen during a heat spell may become withered and cling to the stem, but a fully-weighted over-ripe berry should fall. One example is wild Himalayan blackberries out here that are black-raspberry sized; many of these fall but many remain withered on the plants and can be seen into winter.

I have a tiny percentage of berries in my patch that shrivel and cling, but these are the runts of any particular variety. The normal separation of berry from stem does not occur due to the undersized but ripe fruit.