According to Doctor Bob Technical (Randy Mosher) and his Amazing Wheel of Beer, if I mash 13 lbs. of 2-row malt I should get an OG of 1.070 at 70% efficiency. That's about 17 ºP. If I only get 60%, it drops 2 ºP. That 's 15 ºP or about 1.060. That's pretty strong wort. I'll have to balance it with a series of hop additions. Note that I have modified the original slide rule with a compromise line marked in orange. There really wasn't a spot for North American 2-row pale malt, and I took some thoughts from John Palmer's How-to-Brew (hence the notes) to settle on that line. (I forget what the "80%" is for!) I'm not sure this slide rule of Mr. Mosher's is available any more. That's too bad, I've been using mine for years. I love stuff that doesn't need batteries.
a.d. III Id. Aug.