What he said. Not saying it can't be done, it just isn't easy. I'm sure you've been to gruitale.com?
Mine turned out waaaay too sage-y. But it makes a really good pork or chicken marinade.
For reference, this was the recipe:
Scarborough Faire Ale
6 lbs Light LME
1 oz Parsley (30m)
1 oz Sage, Rubbed (30m)
1 oz Rosemary (30m)
1 oz Thyme (30m)
S-04 Dry English Ale Yeast
Here is a link to suggested adjunt levels: