Cakey,
rinsing stops the cooking process, they need to be firm but squashable between finger and thumb (without just splitting in half when squeezed, they are not ready at this stage). Leaving them in the hot water when the tester is squashable will see the rest go to mushy. This doesn't matter when using them for loosefeed but for hooking (roach, carp, bream,tench) they fly off on the cast.