Author Topic: BIAB- can I do it? and determining boil off rate  (Read 8535 times)

Offline RodMunch

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BIAB- can I do it? and determining boil off rate
« on: February 07, 2012, 11:31:03 AM »
Hello All,
This is my first post.  I have just got started learning the BS program.  I am mostly an extract brewer with 3 partial mashes under my belt.  Almost all the kits are from either Northern Brewer or Midwest Brewing.  I only assembled one recipe myself, a Midas Touch clone which was a partial mash.  I currently do not have the traditional equipment to start all grain, that is the mash tun and such.  The BIAB seems like a go for me!  I do have a nice Polarware 10 gallon pot with spigot and the ability to screw in a thermometer.  I unfortunately only have an electric range right now. 

So first order of business, can I do BIAB? 

First, I wanted to see how long and if I can boil 8 gallons of water, as this is the approximate amount needed for boil volume (it is actually a little more, but 8 is an easy number).  I calibrate my stick with marks so that I can take readings along the boil. 
I start the boil.  On my range with lid on, I can boil the 8 gallons of water in approximately 1-1/2 hours with the lid on.  The boil is not an extreme rolling boil, but the temperature is 212 degrees F.

Also will my bag be enough to hold 12-15 pounds of grain, (wet, I don't know the weight)?  I have a large straining bag fine mesh 18-3/4" x 19" from Northern Brewer.

Next question, why is my boil off rate different from http://sigginet.info/brewing/tools/equipment-profile-helper?

Setting up my equipment profile boil off rate:
I start out by making my equipment profile.  I used the two links as inspiration:
http://www.beersmith.com/forum/index.php/topic,5140.0.html
http://sigginet.info/brewing/tools/equipment-profile-helper
However, from experience with my setup, it just didn't seem the boil off rate was correct.  My Pot is 14" in diameter and 16" high.   From memory, it always seems like my boil off was 1/2 gallon for a 60 minute boil.  So I was surprised when I plug into the profile helper that it said it is 1.12 gal/h.

I went ahead and took measurements of water boiling and here is what I got:
After 60 minutes, take a volume reading, volume is 7 -1/4 gallons  (rate works out to be 0.75 gal/h).
After 90 minutes, take a volume reading, volume is 6.875 gallons (rate works out to be 0.75 gal/h).
Lets do a 120minute boil, take volume reading, volume is 6-1/2 gallons (rate works out to be 0.75 gal/h).
So it would seem that my rate should be 0.75 and not 1.12?  I don't quite understand why my rate is so low compared to the predicted value.  Is it because I only used water to test?

Thanks for any input you may have.


Offline brooklanebrewing

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Re: BIAB- can I do it? and determining boil off rate
« Reply #1 on: February 09, 2012, 07:03:46 AM »
Hello RodMunch,

Not sure I have a ton of insight as I only have 4 BIAB brews under my belt, but none of them on an electric range. Aside from the electric range bit, 8 gallons would be too much on my system. I'm usually right at 7 and that leaves me enough to leave some trub behind and put 5 1/4 gal in the fermenter with an extra quart from the starter. My boil rate is over 1 gal/hr so that would also indicate that you might be starting with too much water. The less water you can start with the better your stove should be able to handle the boil. Not sure if you are just using the lid to ramp up to boil temp but I do not believe you would want to boil with the lid on or you will not drive off the DMS.

As far as your bag size, I would say if it nearly fits in a 5 gallon pail you should be fine. I imagine 12 - 15 lbs. should be somewhere around half or 2/3 of a bucket.

Sorry I have no advice on your boil off rate. I have a wider kettle (18" dia) and my boil rate is somewhere around 1.4 gal / hr.  I hear 10 -15% /hr is a good boil off rate if that helps. Since i'm doing double batches 1.4 gal of 14 gal is right at the low end for me.

That's my insight anyway, hope it helps in some way.

e

Offline RodMunch

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Re: BIAB- can I do it? and determining boil off rate
« Reply #2 on: February 09, 2012, 07:45:30 AM »
Thanks for the reply.  I only use the lid just to ramp up to 212.  I never have the lid on during a boil.  Also, for just the water test, I left the lid off obviously so that I could measure the boil off rate.  That is really helpful giving the evaporation rate of 10-15%.  I am currently at 9.4%/hour (brewsmith calculation).  The pot I have can easily hold 10 gallons of wort with head space, but I admit that my electric range will be at the limit.  I personally didn't think that 1-1/2 hours for 8 gallons of water to boil was too bad for what I have to work with.  I would eventually love to either get a gas stove, or move my operation outside. 

As for the bag, it will comfortably fit my brew pot.  My concern was having the bag tear due to shear weight of the wet grain when I pull it out.  That would suck.  But further reading and watching youtube videos, kind of put me at ease.  Those bags appear to be pretty strong.

Thanks for the insight, it definitely helps!

Offline Kevman

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Re: BIAB- can I do it? and determining boil off rate
« Reply #3 on: March 23, 2012, 07:48:59 AM »
Hey Guys,
After brewing partial mash beer for lots of years I've taken the plunge with all grain brew in a bag.  After a couple of batches now, I have not been getting the efficiency I had hoped for and was wondering if any of you had any advice in this regard.  I have been doing a final grain rinse into a bucket and put this back into the brew pot after it had sit for a while.  Thanks!

Offline bucknut

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Re: BIAB- can I do it? and determining boil off rate
« Reply #4 on: March 23, 2012, 09:22:12 AM »
Kevman, you'll want to do a 90min "mash in", always perform a "mash out" step, stir ALOT at the start of the mash, there is some debate on weather stirring during the mash helps with eff but I do every 15-20 min. Squeeze the sh*t out of the bag, and finally you'll want a very fine crush on your grains, if your LHBS won't let you adjust the mill then double crush the grains.