So episode 231 (as noted by bybyrd) is the one I should listen to, VilleN, to hear all about Johnny Hunter's 3 day technique?
As for these shortened techniques, I have to wonder if the outcome is really the same even if the taste, colour (and perhaps even texture) is similar. According to the article mentioned upthread, the nutrient properties change drastically between 5 and 25 and (less so after) 90 days. I guess that may only matter if you care about something other than getting it done fast and/or being able to say one is including 'black garlic' in a special dish - and, I think I may care as much about the reasons it was 'invented' in the first place - which I think also included preservation and health aspects.