most, if not all dry yeasts, are gluten free. thus you should you dry yeast unless you can get your hands of the wyeast gf. so i'd change the extract to sorghum and yeast to dry. make sure your brewing equipment is very well contained. i know a few people that can get a reaction from just eating/ or drinking something that has come into contact with gluten previously. if you're doing all grain, i'd use millet, quinoa, buckwheat, or something of that sort. you'd have to malt it yourself though, which is another whole issue.