I've just read the book "Guinness, The 250-Year Quest For The Perfect Pint" by Bill Yenne. He obviously isn't a beer geek and a lot of the material was probably pumped into him by the Guinness PR department and it shows. For example when they decided to brew a lager and came up with the name Harp, they converted one of their breweries into a state of the art lager brewery and started brewing an authentic Bavarian Reinheitsgebot lager ..... erm hang on we're talking about bloody Harp Lager in the 60s here, almost as bad as Watneys Bloody Red Barrel

However apart from such hyperbole the book is a great read, and a couple of snippets interested me about current (2007) practices:

They run the beer at 25°C for 60 hours, then mature for a full 3 days
I was surprised to find that the major dark grain is roasted malt in the mash to give a brown colour to the wort, not roasted barley. There is RB, but this is added after mashing in the form of an extract.
There is also a further secret "extract" added later. Whaddya bet it's a small portion of Brett fermented stout?

I wasn't going to do a stout this year but after reading the book I was tonguing for a creamy rich stout, so did one today. I added the Roast Barley to the mashout, and used some acidulated malt in the mash to see if I can get a bit of that hint of lactic.



edit: and I've got a good healthy starter of Wyeast Irish Ale 1084 which I am going to run at 24° - have done so in the past and it works great, I wouldn't mind betting it's related to the Guinness yeast.