I recently discovered hopville and have been happily tweaking away with it's recipe calculator. I was just browsing the featured recipes when I noticed that none of the OG,FG, or ABV calculations in them seem to match mine. For instance, this recipe:
By my calculations, the expected OG should be 1.063, but hopville claims 1.059.
((6×45)+(1×28)+(.5×34))÷5 = 63
Likewise, the ABV calculation at the bottom doesn't appear to use any of the numbers on the recipe page. Using the page's listed (OG-FG)*131.25 yields a different number, as does the same calculation using the listed attenuation.
Is hopville an inaccurate source for brew calculations, or is my math wrong?
Bottled: Modded Sierra Madre Pale Ale, Irish Red, Ska True Blonde Clone, Chocolate Stout (Partial Mash), Dead Ringer IPA (Partial Mash), Cider, Dead Ringer IPA (Extract), Orfy's Mild(AG), Busty Brunette Blonde(AG), Dead Ringer(AG), Chocolate Stout(AG), Pumpkin Ale(AG), Tits Up IIPA(AG)