Using the formula below and the data for Maris Otter malt , I calculated the ppg (SG of 1 lb of fermentable in 1 gal of water) for the Maris Otter Malt that I used in my bitter 2 recipe.
Key
DBCG = Dry Basis/ Coarse Grind
MC = Moisture Content
Brewhouse Efficiency = Your average home brewery mashing efficiency
S.G. = ((((DBCG – MC – 0.002) * Brewhouse Efficiency * 46.214) * 0.001) +1)
S.G. = ((((0.805 – 0.03 – 0.002) * 0.77 * 46.214) * 0.001) +1)
S.G. = 1.02750703494
This equates to 27.5 ppg for Maris Otter malt in my home brewery. This seemed pretty good to me considering that I used a candy thermometer when mashing my grain, and having to go over all my grain with a rolling pin. I will need to pickup a grain mill in the future so that I can have some consistency with my grain.