Tuesday, June 19, 2012

Keeping BIAB The Way It Should Be - Simple

One of the problems with being an engineer is that you always want to find a new way to tinker with things, whether that means adding technology to your home, automating something, or just replacing older technology (i.e. replacing halogen lights with LEDs) to save money.

It's because of this tendency that I don't think I'll ever be able to make a living doing something mundane, no matter how much money it makes me.  This carries over into my brewing as well.  The beauty and simplicity of the Brew in a Bag method runs counter to all of the high-tech complexity that gets my enginerdy juices flowing.

I keep trying to find ways to improve the BIAB process, but all of them add complexity that is unneeded.

After all, isn't the big advantage of BIAB is that it's SIMPLER than the traditional all-grain method(s)?

Could it be that there is nothing to be improved with the Brew in A Bag method?  Say it ain't so!

Here are some of the "problems" I want to solve that I've realized don't really need solving:

1.   Maintaining uniform temperature during mashing is difficult
         
      In my quest for a cool high-tech system, I added a digital temperature controller to my heatstick so that
my mash temperature would be automagically maintained.  Here's a diagram showing it:





Surprise!  The grain bag might as well be a brick wall.  It does such a good job of insulating the interior of the grain bag, that putting the temperature probe in the grain will keep the (digitally controlled) heatstick on for a good long time; long enough to kill any enzymatic activity on the outer edges of the bag.

But alas, if you put the temperature probe at the bottom of the vessel near your heat source, you really have no idea what temperature the grain is at.  So the lesson here is that while a digital temperature controller is nice to have, you really don't need it during mashing if you simply:
        a.  Heat your water to slightly above mash temperature
        b.  Add your grains and stir well
        c.  Wrap your vessel with a blanket or sleeping bag.

It's that simple....the temperature of your grain should remain very close to the desired mash temperature, and if you need to adjust it upward, just apply some heat (propane or heatstick), drain a few quarts out of the bottom and pour it into the grain bag.

BobBrews illustrates this on his site at: http://www.stempski.com/biab.php
Thanks Bob!


















2.   Too much wort is left in the grain bag after mashing

     In an effort to maximize my efficiency, I started thinking about how to get more of the wort to drain out of the bag.  Earlier, I posted that I was going to test my theory that the weight of the grain bag causes inward forces on the grain which inhibits the drainage of wort from the bag.

I asked the biabrewer.info community for feedback and got some great responses.  You can read them here.

The consensus in the brewing community seems to be that the amount of wort lost (undrained/absorbed) in the grain is less with BIAB than in Single Infusion Mashing (.6 liter/kg versus 1 liter/kg of grain), so the mash efficiency contribution from this factor should favor BIAB. 

Two things play into this.  The grain bag provides a porous surface over a majority of the grain allowing wort to drain out.  This compares to a much smaller surface (typically the bottom of the grain bed) in a mash tun/cooler.  And secondly, the inward squeezing force the bag applies to the grains, combined with intentional squeezing many BIAB'ers do pushes more of the wort out.  This squeezing does not happen when using a cooler/rigid mash tun.

I am still contemplating the negative side effects of squeezing.  I'm not talking about tannins here, as pH and temperature are the causes of tannin release.  I'm talking about the compaction of the grains that happens during squeezing that might trap wort in the grain much like a stuck sparge.

I think there may be ways to get slightly more of the wort out, but this just adds complexity and the big advantage of our beloved BIAB method is that it is SIMPLE.  So keep it simple by hanging the bag and letting it drain, or spin it around to squeeze even more out.  You'll still be ahead of the game compared to the alternatives.

3.   Grain needs to be finely crushed to hit OG number

If the grain is finely crushed, more surface area is exposed to the water, and the enzymatic conversion of the malt starches to sugars will happen more completely.  But the downside is that the smaller particle sizes of the grains allow them to be compacted into a less porous glob, trapping that precious wort inside.  From what I've read and my personal experience, the crush should crack the grain into several pieces and separate the hull, but there is really no need to overdo it and end up with dust, as it will either end up at the bottom of your vessel, or contribute to poor bag drainage.

Keep it simple and use the crush as done by your local brewshop.

Until next time...cheers!

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2 comments:

Your good knowledge and kindness in playing with all the pieces were
very useful. I don’t know what I would have done if I had not
encountered such a step like this.

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Your good knowledge and kindness in playing with all the pieces were
very useful. I don’t know what I would have done if I had not
encountered such a step like this.

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