First BIAB attempt this weekend. Absorption rate question

[ClemTiger0408]

I am planning my first ever BIAB - going from extract - this weekend. I plan on making this recipe: https://www.homebrewtalk.com/f78/holly-christmas-ale-145580/

I am concerned about how much water I will need to brew.

I have a 10 gallon kettle. My boil off rate is about 1.5gal/hour. So if I want to end up with 5 gallons, right there I need 6.5 to start. So if that recipe calls for about 14 pounds of grain, and if the approximate absorption rate is 0.15 gallons/pound, then I need another 2.1 gallons. Bringing my total water bill to 8.6 gallons.

So my question is about displacement/absorption. I am worried that with 8.6 gallons of water and 14 pounds of grain, I will overflow the kettle. Is this a legit concern or will the 2.1 gallons of absorption in the grain... be absorbed?

I know this is a weird way to ask this question. Basically, is my kettle big enough?

 

[JDGator]

my guess is it's going to be really close. i would start with your 8.6 gallons and once its to mash temp, take out 2 gallons, add your grain and stir stir stir. once they have soaked up the water, add what water you've saved. if it all fits, perfect. if not, save the water.

That is what i do when i brew a 10gal batch with 20plus lbs of grain in my 16gal kettle. if i need to i just top up with a bit to make sure i have my pre boil volume.

 

[ClemTiger0408]

my guess is it's going to be really close. i would start with your 8.6 gallons and once its to mash temp, take out 2 gallons, add your grain and stir stir stir. once they have soaked up the water, add what water you've saved. if it all fits, perfect. if not, save the water.

That is what i do when i brew a 10gal batch with 20plus lbs of grain in my 16gal kettle. if i need to i just top up with a bit to make sure i have my pre boil volume.

Would I add the 2 gallons back right before the boil?

EDIT: I'm dumb. Re read your comment and I understand.

 

[JDGator]

Would I add the 2 gallons back right before the boil?

EDIT: I'm dumb. Re read your comment and I understand.

no your not dumb, just learning.

Yes, you add it back before the boil. it's just so that if your kettle can't handle the grains and water, it won't over flow. then add back as much water to the mash as you can.

 

[HBngNOK]

I like the idea of removing a couple of gallons of hot water before you add the grain. What you might do with the reserved water is a dunk sparge to rinse the grains? Then add as much of the water back to the kettle as your comfortable with?

 

[1MadScientist]

I am planning my first ever BIAB - going from extract - this weekend. I plan on making this recipe: https://www.homebrewtalk.com/f78/holly-christmas-ale-145580/

I am concerned about how much water I will need to brew.

I have a 10 gallon kettle. My boil off rate is about 1.5gal/hour. So if I want to end up with 5 gallons, right there I need 6.5 to start. So if that recipe calls for about 14 pounds of grain, and if the approximate absorption rate is 0.15 gallons/pound, then I need another 2.1 gallons. Bringing my total water bill to 8.6 gallons.

So my question is about displacement/absorption. I am worried that with 8.6 gallons of water and 14 pounds of grain, I will overflow the kettle. Is this a legit concern or will the 2.1 gallons of absorption in the grain... be absorbed?

I know this is a weird way to ask this question. Basically, is my kettle big enough?

I'm coming up with 8.13 gallons of water for 14 pounds (a 2.26 qt/lb ratio). 84% efficiency into kettle and a 9.58 gallon mash volume (about 1/2 inch from top of kettle). It's doable.

 

[ClemTiger0408]

Can I get some help with this calculator? http://www.brew365.com/mash_sparge_water_calculator.php

Using the recipe in my original post, I am struggling to effectively use that tool. Here's what I entered, what did I do wrong?

Batch Size: 5 gal
Grain Bill: 14.45 Lbs
Boil Time: 1 Hr
Trub Loss: 0 (it won't be exactly zero, but I doubt it will be much)
Equipment Loss: 0 (no false bottom)
Mash Thickness: 1.8qts/LBs (I use the 6.5 gallon pre-boil volume, right??)
Grain Temp: 70
Mash Temp: 152

Wort Shrinkage: 4
Grain Absorption Constant: 0.13
Percent Boiloff: 10

The results it yields is 9.2 gallons which seems too high. Is this because its not intended for BIAB?

 

[ArcLight]

>>and if the approximate absorption rate is 0.15 gallons/pound,

That seems high to me. I do squeeze the bag a bit though.
I don't lose 1.5 gallons for 10 pounds of grain, I'd say its closer to 1 gallon, and possibly less.

 

[Vellum]

I think grain displacement is about 10 oz per pound. I use this assumption in my volume calculators and it works well.

 

[sfgoat]

I only ever paid attention to it once but when did the grain only displaced about .03-.035 gal/pound due to absorption.

 

[Vellum]

I agree with you goat but until the grain absorbs the water I think it is more.

 

[wilserbrewer]

I am planning my first ever BIAB - going from extract - this weekend. I plan on making this recipe: https://www.homebrewtalk.com/f78/holly-christmas-ale-145580/

I am concerned about how much water I will need to brew.

I have a 10 gallon kettle. My boil off rate is about 1.5gal/hour. So if I want to end up with 5 gallons, right there I need 6.5 to start. So if that recipe calls for about 14 pounds of grain, and if the approximate absorption rate is 0.15 gallons/pound, then I need another 2.1 gallons. Bringing my total water bill to 8.6 gallons.

So my question is about displacement/absorption. I am worried that with 8.6 gallons of water and 14 pounds of grain, I will overflow the kettle. Is this a legit concern or will the 2.1 gallons of absorption in the grain... be absorbed?

I know this is a weird way to ask this question. Basically, is my kettle big enough?

I roughly come up with 9.9 gallons of mash volume using the "rackers calculator" can I mash it. http://www.rackers.org/calcs.shtml

Since you are so close, I would mash with a gallon less, and add it back to the mash after it is mixed, either before or after the rest. This is a good work around for a small kettle.

You could also mash a gallon short, then sparge a gallon by pouring it slowly through the bag above the kettle in a colander.

 

[Peruvian802]

This is one reason I love my refractometer and consider a colander over a bucket with a hot water sparge. I can check my pre boil OG and volume, adding 2nd runnings to meet the expected gravity and level.

 

[Epimetheus]

Since you are so close, I would mash with a gallon less, and add it back to the mash after it is mixed, either before or after the rest. This is a good work around for a small kettle.

You could also mash a gallon short, then sparge a gallon by pouring it slowly through the bag above the kettle in a colander.

'S what I do - mash with a little less water and dunk sparge in a bucket. The 8 gallon tamale pot has a pierced Al plate above the bottom and I squash out the water against that.

One suggestion - I use shoulder-length PVC gloves from Harbor Freight when doing BIAB. They protect my arms while handling the hot grain bag. Yeah, it looks geeky. I do not get scalded.

 

[FatsSchindee]

'S what I do - mash with a little less water and dunk sparge in a bucket. The 8 gallon tamale pot has a pierced Al plate above the bottom and I squash out the water against that. One suggestion - I use shoulder-length PVC gloves from Harbor Freight when doing BIAB. They protect my arms while handling the hot grain bag. Yeah, it looks geeky. I do not get scalded.

Are these the ones you are talking about?
http://www.harborfreight.com/oil-resistant-pvc-long-cuff-gloves-99677.html

 

[ArcLight]

Home Depot has some great BIAB gloves, I think its these:

http://www.homedepot.com/p/Working-Hands-Medium-PVC-Coated-Gloves-12520-8/202273287

Its not the length, you need something thick, or your hands will get burned when squeezing