To tell you the truth, I don't think it was in the recipe. I'm kinda hazy on that night (imagine that!), but IIRC he said it was an older beer. So, it's either by chance or technique! Boulder, do you recall?
This is something I think about all the time - Recipe versus process. It seems to me that many people are focused on the recipe. To be sure, this plays an important part, but people tend to ignore the process, which I think is equally, if not more
By analogy, I'm a tuba player, and a couple of years ago I had an antique tuba that sometimes I could make it sound good, other times it was a struggle. I had a lesson with a well known professional, and he made that horn sing. Same horn, different "procedure". One could have an award winning recipe and some folks will get a similar result using it, other won't. These days I'm thinking the process is more important than the recipe, maybe 60/40.