Partial mash - subsitituion of grain for DME

[DarthBeer]

I wanted to see if I could get some input on a recipe for Fosters Lager from Clonebrews. It says to subsititute 1.25 lbs DME for the same amount of 2 row pilsner malt. The chart in the back of the book lists DME 1.044 gravity and pilsner malt as 1.037.

Questions being is that difference enough to need to add more of the pilsner malt to make up the .07 difference? The LHB recommended using 2 lbs of the pilsner malt instead of the 1.25 lbs listed in the books recipe.

I would think .07 would be a negligable difference. Although I've only been at this a few months.

 

[david_42]

I would bump the pilsner for two reasons: 7 points is a 20% difference and your efficiency will probably be on the low side the first couple times you do a PM. 37 points is the maximum and if you run 70% extraction efficiency you'd be down to 26 points.

44* 1.25 = 55
2*37*0.7 = 52

 

[ajf]

+1 to what David said, and to what your LHBS said as well.

-a.

 

[DarthBeer]

I would bump the pilsner for two reasons: 7 points is a 20% difference and your efficiency will probably be on the low side the first couple times you do a PM. 37 points is the maximum and if you run 70% extraction efficiency you'd be down to 26 points.

44* 1.25 = 55
2*37*0.7 = 52

Could you recommend a good link to look further into the math/formulas behind this?