Fermentation is an inexact science

Three Secrets To Crispy Pickles
July 12, 2012
http://www.npr.org/sections/thesalt/2012/07/12/156619002/three-secrets-to-crispy-pickles-and-a-lost-recipe-found

About the timing:
Fermentation is inexact science and you can’t ever know for certain that it’s going to take exactly seven days or 10 days, which is why I recommend that you kind of leave one cucumber towards the top of the jar that you take little slices off of as they ferment until it reaches the flavor that you’re looking for.