Biab mash and strike numbers check

1.5 q/lb mash thickness. 153 strike temp. 70f temp of grains. 167 degree strike water temp. 17.5 lbs grain at 1.5 q/lb mash thickness takes up 7.96 gallons in kettle with 6.56 gallons starting strike water. 2.18 gallon loss to grains assuming .125 ga/lb absorption. 2 gallons sparge water for 6.3 gallon pre boil volume.


Anyone want to check my numbers on this? I'll be maxing out my 8 gallon pot. Wanna get the best efficiency I can. Thinner mash, slightly lower mash temp, and a decent dunk sparge including letting drip as much as possible and squeezing that bag. 1.5 q/lb is of course the thinnest I can go with my size pot.

Anyone willing to help out a humble chum?

8.0 gal kettle
6.3 gal start boil
5.0 gal post-boil
Mash-in @ 1.5 Liters per 1 lb. grain = 6.56 gal strike water at 164 F to reach 153 F target mash temp
Mash-out with 2.42 gal at 167 F

Even with grain absorption, you'll exceed your 6.3 gal target start volume with a 1-1/2 mash-in ratio when you include the mashout.

Try going with a 1-1/4 ratio instead. You will stilll be slightly over 6.3 gal, but not as much as you would with a 1-1/2 ratio.

This is why we recommend 10-15 gal kettles instead of 8

Thanks for the response!

Where in my calculations am I off?

So 1.25 quarts/lb. is 1.5 liters/ lb. mash thickness ? ( I believe you did the calc with 1.84 l per quart right ?)

Liters and quarts are slightly different.

For accuracy purposes, I would measure with one or the other... not both. I used liters.

bobbrews said:

Try going with a 1-1/4 ratio instead. You will stilll be slightly over 6.3 gal, but not as much as you would with a 1-1/2 ratio.

This is why we recommend 10-15 gal kettles instead of 8

Click to expand...

I'm definitely trying to keep brewing as economical as possible at this point and another 100 plus bucks on even a polarware 10ga is too much.

I was reading quite a bit about thinner more fermentable wort ( higher grist/water ratio) vs. more sparging for efficiency. Because this is such a higher gravity wort I'm wondering if it might be better for the mash to be thinner with a slightly lower mash temp say maybe 152 with possible 2 pt. loss during mashing. But then again if the mash is thicker I would need a decent sparge to rinse as much sugars as possible. If with the thinner mash I could still get a little sparging done. All in all I don't care to lose 3% efficiency if I can get a wort that is more fluid and more fermentable.

bobbrews said:

Liters and quarts are slightly different.

For accuracy purposes, I would measure with one or the other... not both.

Click to expand...

I'm only measuring in quarts for my numbers, mash thickness, sparging etc. Thnx again Bobbrews!

unless you've done it before, i'd go with a slightly thicker mash, it can get quite messy when pushing the limits of the pot, especially when pulling out the grain bag. the efficiency differences should be minor

djbradle said:

Where in my calculations am I off?

Click to expand...

your #s weren't off

Duly noted. Not afraid of anything messy. I'm pretty careful with these kinds of things and use due diligence before I take action. I'd rather get the best brew I can since I'm putting so much time into the brewing process.

Thanks again for the response! Means a lot.