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deprecated
Joined: 16 Oct 2012 Posts: 5
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Link Posted: Fri Oct 11, 2013 3:53 pm Post subject: Need help figuring out MLT temp. issues, please. |
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I'm having a terrible time maintaining mash temperatures where I would like them to be. Mashing with PID set to 153, the majority of my mash sits at 145 except for area immediately around HERMs return.
My setup:
Approx. 32G kettles (19.5" diameter by 26" H)
- HLT is setup identical to Kal's guide but does use center/bottom drain.
- MLT:
False bottom is made from SS - 0.06" Thick / 0.09375" dia. holes / 0.15625" stagger.
I do have 3G of deadspace below false bottom and uses a center/bottom drain.
The return from HLT HERMs coil passes through an analog temp. gauge (outside HLT wall)
which is attached to street elbow (inside HLT wall) then silicone return hose inside MLT.
- Using 2 809 pumps.
Things I've noticed:
- PID temperature always matches analog temp. gauge on MLT return.
- Wort temperature coming out of silicone hose in MLT is within a degree of PID and
analog gauge, as would be expected.
- Grain bed seems to compact often and slow down recirculation quite a bit.
- With 32 lbs grain (2-Row, Crystal, Munich) and a few handfuls of rice hulls this still occurs.
Frequent stirring does help.
I'm guessing at this point....
Maybe I'm losing too much temperature through 3G of deadspace?
Perhaps I need to more evening distribute wort back into MLT (rather than just return hose as in guide)?
Any ideas???
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skelley
Joined: 24 Feb 2012 Posts: 210 Location: brookfield, wisconsin
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Link Posted: Fri Oct 11, 2013 5:29 pm Post subject: |
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How do you know the temperature of the mash?
If you have to slow ciruclation you most likely have a partially stuck mash maybe even with some channelling. I had a lot of trouble with this until I fixed my grind. Take a look at the ground grain and make sure husks are largely intact and that you don't have a bunch of flower. I think the grind is the single most important piece of this set up.
Not sure if this helps?
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deprecated
Joined: 16 Oct 2012 Posts: 5
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Link Posted: Fri Oct 11, 2013 7:00 pm Post subject: |
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Quote: | How do you know the temperature of the mash? |
I used 2 different digital thermometers and sampled in different spots. On average 7 degrees off from my PID setting and intended mash temp.
Local homebrew shop crushes the grain as I don't have a mill but there isn't much flour in there. They've been in business since 1984 and I'd be surprised if they weren't crushing it as good as a person could.
One thing I left out is that I am averaging 73-75% efficiency which has caused me to wonder about channeling and if I shouldn't find a way to more evening return the wort into the MLT. My efficiency is consistent which is great but I've always thought that to be low for HERMs.
Another thought was maybe to let the grain bed settle for 10-15 minutes before starting recirculation through the HERMs.
I appreciate the suggestions. If nothing else you've reminded me that I'd like to get a mill and be in control of the crushed grain variable
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11116 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11116 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Link Posted: Fri Oct 11, 2013 8:03 pm Post subject: |
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deprecated wrote: | Local homebrew shop crushes the grain as I don't have a mill but there isn't much flour in there. They've been in business since 1984 and I'd be surprised if they weren't crushing it as good as a person could. |
It's not about how 'good', it's that they're probably crushing a lot finer since most of their clients do batch sparging and crushing stuff a lot finer gives them better efficiency but does the OPPOSITE for recirculating fly sparging setups like this one as it impedes flow.
You need to crush a lot rougher probably, in the 0.040" to - 0.060" range or so (see the grain mill instructions or the Brew Day Step by Step instructions).
Your false bottom could be causing issues. Not seeing it or using it, it's hard to tell.
Quote: | Another thought was maybe to let the grain bed settle for 10-15 minutes before starting recirculation through the HERMs. |
No, I don't see how that has any benefit. I dump the grain in, add any salts, stir for ~5 mins so that I can take an accurate pH reading and then open up the pump 100% right away. If you don't use salts, you could just dump in and not even bother stirring and open the pump to 100% as it'll self mix. Doughballs aren't really possible with recirculating systems.
Kal
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deprecated
Joined: 16 Oct 2012 Posts: 5
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Link Posted: Fri Oct 11, 2013 8:55 pm Post subject: |
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Ok, I didn't even think about benefits of mill settings being different between batch and fly sparging...
Thank you both (Kal and Skelley) for pointing this out. Sounds like Skelley was spot on but sometimes I have to have things spelled out like you did, Kal.
Guess I do have a grain mill in my future
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11116 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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g8tors
Joined: 05 Oct 2011 Posts: 211
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Link Posted: Sat Oct 12, 2013 3:14 pm Post subject: |
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Things I have learned over that past year of using my system:
1. Like everyone else has said, a coarser grind on the grain is better
2. Slowly increase the recirculating mash flow over a few minutes . I have chugger pumps and usually open the valve no more the 75%. My temp rise times are right on with kals.
3. Do not let the water level fall below the grain bed. This compacts the grain bed and will lower your efficiency.
Scott
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