AG to Partial Mash

I've seen a number of threads recommending conversion amounts for grain to all-extract. (e.g. LME = 0.8125 x grain amount, DME = 0.6875 x grain amount) But I'm curious about any general recommendations there might be for converting from AG to partial mash.

I've looked at some recipies listed in BYO magazine that list AG and their PM equivalents and there seems to be quite a bit of variation from one to another. These recipes recommend replacing the primary malt with anywhere from about 12 to 25% as much DME and 35 to 56% as much LME. For example, one recommends replacing 9 lbs 2-row pale with 2lb-6oz LDME (22%) and 3.3 lbs LLME (37%). Another recommends replacing 8.5 lbs 2-row pale with 1.25 lbs LDME (15%) and 4.5 lbs LLME (53%). Is there a general guideline or will it always vary for AG to PM?

Will ProMash or similar software do an AG to PM conversion?

Thanks,
SP

i dont know any equation but its mostly common sense. youre going to use all the specialty grains from the AG recipe, and you'll need 2-3 lb.s of base malt to help convert those. from there just take the remaining base malt and use about 60% of that in extract form. so if there were 8 lb.s of base malt, and you use 2 in your PM, then you'd want probably 3-4 lb.s or so of extract. use pro mash and get the OG to what the recipe suggests and it will be right.

OK, so 2-3 lbs of base malt for the PM will work regardless of the amount of base malt in the AG recipe? Thanks drengel.

SP

yeah, you wont be able to fit much more in a grainbag and still effectively sparge it, so replace the rest of the base malt with extract until you get the proper OG calcualation.