Nothing wrong with root veg and tomatoes though ... eg Spanish Potatos and many stews and loads of curries use toms to sweeten. But tomatoes with wine .. yes ....... but doesn't sound right with Guinness.
I also just think that the combination of Guiness and Rosemary to me equals a sort of soapy metalic taste?
Interesting to hear how it turns out!

Gotta disagree again.
I like a root stew to be earthy and hearty in taste,the tomatoes simply makes this too acidic.
But taste,of course,is subjective.
Guiness and beef stew with rosemary dumplings would appear to be a fairly common recipe - even with tomato puree !
http://www.waitrose.com/home/recipes...dumplings.html
I'm on a bit of a low-carb gig at the moment in order to fit into my budgie-smugglers on an upcoming beach holiday so lunch has been cauliflower,spinach,scallions,garlic,chicken stock and oyster sauce blitzed into a soup with garlic roasted chicken added. Not bad,but horrendously green and there's a big pot of the bugger to plough through now !