why do the system add addition 6.7 L water everytime.

[Brewer #441673]

Hello everyone!
I'm new here and excited to be part of this community. I'm looking to brew a Leffe clone and have a Brewzilla 35L as my brewing vessel. I'm using 5.23 kg of grain and have calculated the strike water to be 15.69 liters with a thickness of 3. However, the system is adding 6.7 L more, which I'm not sure about. I'm afraid that if I add 22.4 liters of water, the thickness might be too low.
Could you please help me understand why the system adds an additional 6.7 L?
Any advice or guidance would be greatly appreciated!

Water	Liters
Strike water volume at mash thickness of 3 L/kg (includes 6.7 L addition)	22.4
Mash volume with grains	25.8
Grain absorption losses	-4.2
Remaining sparge water volume	4
Pre boil volume	22.2
Boil off losses	-3.3
Post boil Volume	18.9
Kettle losses	-0.9
Going into fermentor	18
Total:	26.4

 

[Donoroto]

Hello everyone!
I'm new here and excited to be part of this community. I'm looking to brew a Leffe clone and have a Brewzilla 35L as my brewing vessel. I'm using 5.23 kg of grain and have calculated the strike water to be 15.69 liters with a thickness of 3. However, the system is adding 6.7 L more, which I'm not sure about. I'm afraid that if I add 22.4 liters of water, the thickness might be too low.
Could you please help me understand why the system adds an additional 6.7 L?
Any advice or guidance would be greatly appreciated!

Water	Liters
Strike water volume at mash thickness of 3 L/kg (includes 6.7 L addition)	22.4
Mash volume with grains	25.8
Grain absorption losses	-4.2
Remaining sparge water volume	4
Pre boil volume	22.2
Boil off losses	-3.3
Post boil Volume	18.9
Kettle losses	-0.9
Going into fermentor	18
Total:	26.4

Persobally, I ignore the water calculations. It is finicky depending on all the equipment and recipe settings. I just go with experience: prepare 8 gallons with brewing salts, drain off 1.75 gallons for a sparge/rinse, brew with the 6.25 gallons. At the end I end up with 5.5 gallons plus or minus a quart. Good enough.