10-11 ABV%, ok. So 2,5lbs per 16,9-18,9 liters, so that'd be 60-67g per liter.
What I know, grains have unfermentable carbohydrates, which is for the drinkers taste buds but not for the yeasts food. Mead... Sugar is easy to ferment. If there were anything unfermentable it'd have to come from...