FINAL GRAVITY PODCAST

BIAB stands for Brew In A Bag – it is an AllGrain brewing process pioneered by the Aussies.  The concept is simple, requires a minimal investment inequipment (over extract brewing) & can produce great beer.

To make a beer using BIAB you will need a kettle large enough to hold all of the water needed to make the batch (strike water) as well as all of the grain needed for the batch.  Usually a kettle with capacity 2.5-3X the size of your largest batch size will be a safe bet.  If you do not have a kettle large enough you can sparge in a 5gal bucket or separate vessel.  You can use the calculator found here to find out if your vessel is large enough to accomodate your grain bill and strike water.  You will also need a bag made out of Polyester or Nylon Swiss Voile, this is a sheer curtain material that is extremely strong, durable and has a very fine mesh. 

You can make your own bag or purchase one from an online vendor like this one.  Ideally you will be able to fit your entire brew kettle inside your bag, I've also found that a "V" shaped bag with a taper towards the bottom is better for draining the wort from the bag. 

My process for BIAB is very similar to anyone elses process for producing an All-Grain batch of beer. 

1.  I start by heating my entire volume of strike water for my batch of beer. 
2. While heating my strike water I crush my grain, I mill my grain pretty finely.  Nothing makes it through the tight weave of the bag. 
   
3. Once I've hit my strike temp I place my bag in the kettle and clip the bag to the top of the kettle to hold it open, then I pour in my milled grain.  After mixing it well and breaking up any doughballs I check my temps to make sure I've hit my mash temps.  One of the great things about BIAB is that you can add heat to your mash just by lighting your burner, so if I'm a bit low I add heat.  If I'm too high I stir or recirculate with my pump until I hit my temps.  (Be sure to raise the bag off of the bottom of the kettle while adding heat so you don't accidentally scorch your bag.)  
4. After my temps are stable I put my lid on the kettle and wrap it in a few towels I keep outside to help insulate it.  I check my mash every 15mins and stir as well as add heat to stay at my mash temp. 
5. Once I've mashed for 60 mintues I raise the temperature to 170F to mash out and pull the grain bag out of the kettle.  I hold it above the kettle for 4-5 minutes and allow it to drain, then I move it to a bucket to allow it to drain a bit further as I heat my kettle to a boil.  (Something to note, I've found that for a 60min mash I get 76% efficiency, with a 90min mash I hit 83%)
6.  I add the remaining wort from my bucket to my kettle and check my volume and pre-boil gravity and make adjustments as needed.  If my volume is low/high I can adjust my hop additions to compensate.  Similarly if my gravity is high/low I can adjust my hop additons or even add DME to hit my projected gravity. 
7.  After that it's business as usual; boil, add hops, chill, knock out in to the fermenter & pitch yeast. 

Some things that were mentioned on the show that may make things easier for BIAB Brewing include: 

•  A pump (like the popular Chugger Pump) for recirculating your mash
  
• Using a basket (like those in the Bayou Classic pots) to hold your bag
• A hoist or somewhere to hang the bag after pulling it out of the kettle
  

Websites with info on BIAB

http://www.bagbrewer.com

http://www.rackers.org/calcs.shtml

http://biabrewer.info/

http://www.beersmith.com/blog/2009/04/14/brew-in-a-bag-biab-all-grain-beer-brewing/

http://www.thebrewingnetwork.com/forum/viewtopic.php?t=4650

http://beerreviewdude.com/biab-calculator/