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Cooler System Efficiency

bitty1088

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I have been brewing the same beer now several times (gallon batches in a two 10 gallon igloo system) trying to get my system and technique dialed in but can't seem to get the efficiency I want out of my system, Beersmith is measuring it at 52%.  The last batch I did we were meticulous about all of our steps and temperatures.  We increased hot liqueur temperature from 168F to 170F and made sure to do a good long sparge (we are fly spargeing).  Gravity about 3/4 of the way through the sparge was 1.066, target preboil was 1.047, and ended up with a preboil of 1.034.  I can't figure out what is going wrong and how the gravity could drop so low so quickly.  The one thing I did note was that the mash temp after the 1hr rest was down to 144F (strike temp was 162F and it was exactly 152F when the lid went on.  I've never taken the temp after the rest.  The end result was a OG of 1.042, the estimated OG was 1.057.

Any thoughts on what I'm missing here?
 
Did you hit the pre-boil volume exactly where BS2 thought you'd be, at the target of 1.047? 

If SG was 1.066 at exactly 3/4 of the way through sparging, and then fell to 1.034 after the 1/4 of sparging, that would mean (roughly) that you diluted what you already had (the 1.066) by ~50% with only 25% more sparge water. 

It seems more likely that you sparged longer than intended, and diluted the wort past the target of 1.047. 

The temps you mention are not meaningless, but the important factor of wort collection is volume.  The smallest deviation in volume has big impacts on gravity.  The proof of that is your 1.066.......you already had a bigger wort than you would have finished with had you hit the 1.047 target and boiled for an hour and reached ~1.057 or so. 
 
bitty1088 said:
I have been brewing the same beer now several times (gallon batches in a two 10 gallon igloo system)


You're brewing a gallon in 2 separate 10 gallon coolers? How does that work?

Perhaps your grain crush is at fault. This is the most likely scenario. Look for uncrushed grains or large chunks that remain hidden in the husk next time.

Perhaps your mash tun isn't draining fully. Are you using a bazooka screen in your mash tun?

Perhaps your fly sparge water is channeling instead of rinsing the grains. This is unlikely, but not impossible.

Another remote possiblity is that your not compensating for temperature while measuring gravity runnings with a hydrometer.

Also your thermometer might also be off, it might say your mashing at 152, but perhaps it could be 5 degrees off and your really ending up at 139*F

Another possibility is that the software is messing up your efficiency numbers. Are you talking about Mash efficency or Measured Efficiency? You can try this calculator to doublecheck:
www.brewersfriend.com/brewhouse-efficiency/
 
Sorry, that was a typo.  I'm brewing 5 gallon batches using a 10 gallon igloo for the HLT and a 10 gallon cooler for the mash tun, which has a false bottom not a bazooka filter.
 
If you have a refractometer, or could buy one (they've gotten pretty cheap on ebay), then you could monitor the SG as you collect wort. 

If you know how much you typically boil off in gravity points, say ten points increase is typical, then you could stop collecting wort when you hit reach ten points shy of the ultimate OG goal for the beer.  I.e., stop collecting at 1.047 and then boil until you reach 1.057 and flameout. 

At least your beers would turn out as wanted while you're dialing in the water math on your system. 
 
Thanks for the suggestion Malt, that was what I was thinking would be the next logical step.

I'm not sure I could have sparged to long b/c I'm spargeing based on a specific amount of hot liqueur rather than time or gravity reading. Is it possible the calculations could be wrong?  Up until now I have been following the BS2 brewsheet for volume and just running with it.  Basing the wort collection on either volume or OG makes sense. 
 
Not sure how much this affects the overall efficiency, but sparging as slowly as possible does help.  If you're fly sparging and you rinse too quickly, then sugars get left behind and you have the correct amount of wort but less sugar in that wort than expected. 

And the quality of the crush, and the temps do matter, but from my own frustration figuring out the water math when I started AG, I know that volume is the primary factor. 

If you are absolutely positive your Equipment Profile is accurately set up, and that you're executing to those numbers, then I'd recommend slowing down the sparge, and inspecting your crush of the grains, etc.  You can also use the refractometer to monitor the mash and ensure conversion is complete.  (Just take Brix readings and when you get three Brix readings all the same, conversion is done.) 

Also, are you losing any large amount of wort along the way?  I choose to leave a gallon in the boiler, so that does hurt my overall efficiency according to BS2.  So, my mash efficiency is fine, usually between 79 and 83%, but the overall efficiency is much worse because of that gallon I lose to trub each time. 
 
I have to +1 to sparge time.  I have found in a few years of fly sparging that my SG goes up pretty dramatically when I sparge super slow.  A couple of times I grew impatient and my SG was lower, even on repeat beers.  A trickle seems to work the best in my experience.  BUT....after batch sparging for the first time and hitting my numbers on the nose, I'm probably hooked on the simplicity factor and the significant time savings.
 
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