McTap said:
the OG is turning out correct so I'm not sure what to do there. Cheers.
So, what you're aiming for is 27 liters at 1.052 OG. All of the replies above are telling you the answer, but let's put it together, anyway.
The first thing is to apply your real world results to the equipment profile you're using. The second thing is to be more consistent about your production. ...Or just live with a delicious beer, with no care for volume.
Based on Gravity points, you're consistently right around 3.58 l of trub.
Your stats say you're consistent about your pre and post boil gravity.
Everything else is variable, but shouldn't be.
Boiloff:
Recipe 1: 23.6%
Recipe 2: 22.4%
This is a tolerable difference, but represents much more than you need if it's a 60 minute boil. Somewhere closer to 12 to 15% is normal in 60 minutes. Your equipment profile is probably in that range. This is a significant part of your lost volume.
Mash Efficiency:
Recipe 1: 71.68%
Recipe 2: 64.44%
These are low extraction numbers for most types of mash and sparge methods. You may need to mill more tightly and/or monitor and adjust your mash pH.
Brewhouse Yield:
Recipe 1: 86.67%
Recipe 2: 85.43%
This is the percentage of post boil volume that gets to your fermenter. This is NOT the same as Brewhouse Efficiency, but it is a factor.
Brewhouse Efficiency:
This is the mash percentage multiplied by the yield percentage.
Recipe 1: 0.7168 * 0.8667 = 0.6328 = 63.28%
Recipe 2: 0.6444 * 0.8543 = 0.5505 = 55.05%
So, now we know how you got your volume and gravity from 6.2 kg of malt. The next question is what amount of malt you'll need to get 27 liters at 1.052, right?
Since we know the trub amount is constant, we use that to figure the Brewhouse Yield. Dividing the 27 liter yield by the 30.58 kettle volume, we get ....? ....Anyone?
Right! 88.29% yield. Multiply that by the
lower of the two mash efficiencies and we get 56.9% Brewhouse Efficiency. This is now how you'll discover the malt required to reach 1.052.
Differing malts have differing extract yields. BeerSmith calculates each malt separately, then uses your equipment profile and Brewhouse Efficiency number to calculate the OG.
Using a rough calculation, I think you'll need 9.25 to 9.5 kg of malt to reach your goal.