You don't find too many recipes that begin with, "First a note about substituting ingredients or tools. Don't. This method has been exhaustively tested and retested for excellence and the smallest variation can result in catastrophic and unintended consequences."
Somehow, that deserves to be respected, and when the blog post is entitled "Perfect" withoutany reference to what's actually inside (the word "martini" doesn't appear in the first four paragraphs)...well, then, this is clearly something to take very, very seriously.
This is certainly the most specific recipe I've ever seen for a cocktail, but not the most complicated. When I run out of vermouth, I'll be restocking with this guy in mind. I'll let you know how it goes.
And, for an equally careful and worth-the-effort approach to making the perfect Old Fashioned, check out the ManMade how-to here.
[top photo: Cocktail from BigStock]