water loss on corn mash

[stangman69]

Just doing my 1st few corn mashes , how much extra water do i need to add to end up with a full 3 gallons ? 9 lbs of corn Thanks all

[greggn]

Just doing my 1st few corn mashes , how much extra water do i need to add to end up with a full 3 gallons ? 9 lbs of corn Thanks all

Using feed-store, whole kernel corn (milled to coarse flour) I mash:

22 lbs in /10 gallons which produces, when strained through 600 micron filters, 7.5 gallons of wash at 16.0 brix (1.066 SG).
After fermentation, that fills a 6 gallon carboy to the top. I could go deeper but usually don't.

Divide that in half and that should be close to your target.

[stangman69]

oh i do use my shop press to get it all out form grain bag

[Homebrewer11777]

I think a lot will depend on your process. Are you using a bag and squeezing? Are you fermenting on or off the grain? I'm trying to figures this out too.

I don't bag or squeeze and last batch my mash volume was 28.5 gallons with 30# corn and 10# malted barley and 10# malted wheat. I don't measure water into the mash...I just top up the mash to target volume at end of the mash when I am chilling to pitching temps. Then ferment on the grain and collect the liquid wash (beer?) after fermentation is complete.

Based on grain absorption factor I've used in beer brewing of 0.13 quarts/lb grist and expected volume of solids in the mash of 0.36 quarts/lb that there was a theoretical collectable wash volume of 22.4 gallons with good lautering technique. Could be a bit more with aggressive squeezing.

To collect the beer I pressed a hop spider into the middle of my fermentor and siphoned. I allowed the spider to refill a few times to pull out extra beer. I ended up with 17.25 gallons of 9.3% ABV. I called that a lautering efficiency of 77%. So left behind about 5.1 gallons of collectable beer. I was ok with this outcome and will see if that is reproducible.

Only planned change is that next time I plan to ferment a sugarhead on top of the spent mash. Will add sugar, backset and water to reach same original mash volume and original gravity and let that ferment out. When I siphon off the sugarhead it will be mixed with the previously lost AG beer...

[stangman69]

yes a bag and my shop press so i get ever drop out, and off grain

[Homebrewer11777]

ok so 9# of grain will be about 0.81 gallons solids, plus about 0.3 gallons absorbed by the solids. If you want 3 full gallons your mash volume should be 4.1 gallons. Call it 4 gallons...

That is the total mash volume at end of the mash...not water to add. YMMV but seems like reasonable starting point.

[stangman69]

bingo was just what i was going do !!! thanks !!!