The Bounce Test
Cranberries have a famous test. It’s called the bounce test. What you do is take a cranberry and drop it onto a hard enough surface and see if it bounces. It should.
Ripe cranberries are springy and not firm or soft.
If they are too firm then they are not yet ready. If they’re too soft, they’re more than likely overripe.
If the cranberries you are about to pick are a crimson red or a bright red then that’s a good sign that they are ripe. A green cranberry, like a banana, is not yet ready. A dark purple color means it’s too late.
Cranberries have to be picked at the right time. Unlike bananas and other fruit which continue to ripen after they are picked, cranberries do not and so it is imperative that they are picked at the optimal time.
Bright red, bouncy berries are what you’re looking for.
Hope this helps.