Mash water question

[YeastFeast]

I'm preparing to do my 1st all-grain recipe. In doing so, I've checked some online Mash calculators and I don't understand the numbers. If I'm shooting for 6.25 gal pre-boil, then why do I need around 8.25 gallons of water between my strike water and sparge water?

Where does the missing 2 gallons go from the strike water? Soaked up in the grains? And we don't lose any water during the sparge because the grains are already fully saturated??
Thanks!

For example from Brewtoad:
Strike grains with 5 gal of water at 167.5 °F.
Mash at 155 °F for 60 min.
Vorlauf and lauter 3 gal in your first runnings.
Add 3.25 gal of sparge water at 168 °F.
Vorlauf and lauter 3.25 gal in your second runnings.
Your combined runnings should be 6.25 gal.

 

[chickypad]

It would mostly be from grain absorption, about 1/2 quart or .125 gallon per lb for a regular tun (not BIAB with squeeze). Also would be factored in any mash tun deadspace that you entered in the calculator. The grain is already saturated and the dead space filled with the mash water so yes that is why you get the full amount back from the sparge.

 

[cyberbrew]

^^This...

 

[brewkinger]

Yeah... what chickypad said, except with one small tweak.
The grain absorption is correct BUT not dependent on the tun.
The amount of grain absorption is dependent on the grain quantity.

Dead space is tun dependent though.

 

[YeastFeast]

I'm using a 10 gal igloo cooler with a false bottom. So, dead space would be the amount of liquid that can't be sucked up by false bottom hardware. I suppose I can determine that by filling it up a few inches and draining it to see what's left over.

 

[brewkinger]

I'm using a 10 gal igloo cooler with a false bottom. So, dead space would be the amount of liquid that can't be sucked up by false bottom hardware. I suppose I can determine that by filling it up a few inches and draining it to see what's left over.

Exactly this ^^

Fill it a couple of inches over the top of the FB and let it rip....

This process should be included as mandatory to EVERY new AG or PM brewer to help dial their system in with loss calculations.

The same can (and should) be done with your boil kettle if you have a manifold or FB in that as well.
:rockin:

 

[chickypad]

Yeah... what chickypad said, except with one small tweak.
The grain absorption is correct BUT not dependent on the tun.
The amount of grain absorption is dependent on the grain quantity.

Yeah I was referring specifically to BIAB in a kettle or cooler - if you squeeze the bag it's in the range of .08 gal per lb loss.

 

[brewkinger]

Yeah I was referring specifically to BIAB in a kettle or cooler - if you squeeze the bag it's in the range of .08 gal per lb loss.

oh yeah.... now i get it.
:cross:

 

[pricelessbrewing]

What the above said, there's a couple losses involved in a brew day. Don't forget that mash/strike volumes will be about 2% higher and boil 4.4% higher due to thermal expansion.

Boil off 1~ gal/hr depending on environment and kettle width
grain absorption: 0.08 gal/lb for biab. 1.25 gal/lb for traditional mash tuns.
Hop absorption: 0.0365 gal/oz ish
Mash tun deadspace: volume below your bazooka tube, false bottom etc that won't get picked up after the tub is drained. Usually about a quart or two
Kettle loss from break material: depends on preferences, can be a half gallon to 0. I dump it all in and let is settle in the fermenter.
Fermenter loss from trub: about 10% of into kettle volume, depending on yeast used and some other factors.

 

[brewkinger]

What the above said, there's a couple losses involved in a brew day. Don't forget that mash/strike volumes will be about 2% higher and boil 4.4% higher due to thermal expansion.

Boil off 1~ gal/hr depending on environment and kettle width
grain absorption: 0.08 gal/lb for biab. 0.125 gal/lb for traditional mash tuns.
Hop absorption: 0.0365 gal/oz ish
Mash tun deadspace: volume below your bazooka tube, false bottom etc that won't get picked up after the tub is drained. Usually about a quart or two
Kettle loss from break material: depends on preferences, can be a half gallon to 0. I dump it all in and let is settle in the fermenter.
Fermenter loss from trub: about 10% of into kettle volume, depending on yeast used and some other factors.

FIXED THAT FOR YOU.

 

[pricelessbrewing]

Yup, was typing on my phone thanks for the edit

 

[brewkinger]

Anyone would have done the same, we take care of our own around here.

 

[YeastFeast]

Thank you all for your input, I've learned a lot and am ready to roll on my first all-grain!