|
|
|
|
 |
|
|
| View previous topic :: View next topic |
| Author |
Message |
rtucker
Joined: 14 May 2016
Posts: 22
Location: Illinois
|
 Link Posted: Mon Jul 17, 2017 12:42 pm Post subject: Stuck Mash (Failure to follow instructions?) |
 |
|
I've brewed a number of times on the system. 20 gallon Blichmann's, Blichmann false bottom, and March 815 pumps. I have experienced a stuck mash on probably more than half my batches, most recently yesterday. I'm swearing a LOT. I happened to go back an look at the Kal's brew day steps posted on line. I have not been shutting my wort pump off during dough in. Is this the cause of my problem? I understand that I need a good grain bed for proper flow, but what's going on here that would prevent a grain bed from forming while the pumps are running? Remember there's no such thing as a stupid question.
_________________
You're not a country unless you have beer
Roger Tucker
|
|
| Back to top |
|
 |
kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11120
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
|
|
| Back to top |
|
|
rtucker
Joined: 14 May 2016
Posts: 22
Location: Illinois
|
| Link Posted: Mon Jul 17, 2017 1:19 pm Post subject: |
|
|
In general the grist composition is 1.5 qts/lb. I have the gap on the mill set to .045".
I don't think what I experienced yesterday was a problem with the false bottom being clogged. The level on the sight glass never dropped. It was a 5 gallon batch and the sight glass was hanging around 7 gallons or so. I disconnected the hose from the pump and blew into it to try and clear it. I was able to blow plenty of air up into the mash tun but couldn't seem to get the flow going. After working at it for about 10 minutes, something happened and wort started coming out of the hose freely. I hooked it back up to the pump and it was good after that.
_________________
You're not a country unless you have beer
Roger Tucker
|
|
| Back to top |
|
|
rtucker
Joined: 14 May 2016
Posts: 22
Location: Illinois
|
| Link Posted: Mon Jul 17, 2017 1:28 pm Post subject: |
|
|
Disregard my comment about the sight glass. I'm realizing that the sight glass is above the false bottom so that isn't really an indicator.
_________________
You're not a country unless you have beer
Roger Tucker
|
|
| Back to top |
|
|
McGruber
Joined: 12 Aug 2014
Posts: 237
Location: Idaho
|
| Link Posted: Mon Jul 17, 2017 8:58 pm Post subject: |
|
|
Are you circulating water through the HERMS coil to heat the mash tun? Is wort reciruculating back into the MLT as you mash in? It sounds to me like your pump isn't primed, but that doesn't make much sense if you've been circulating strike water. I've had a bunch of frustrating brewing days because of this. When I have a stuck mash, usually my sight glass level drops below the mash level and then I know I'm in for some troubleshooting.
Some suggestions based on similar problems I've encountered:
1.) Turn off your MLT pump when you mash-in. From experience mashing-in this way and troubleshooting stuck lauters I do think running it makes for a plugged screen.
2.) I've found that it works better to "underlet" the mash screen - which is where you run HLT water into the BOTTOM of the MLT. This forces a surprising amount of air out from under the screen which can contribute to stuck mash/ poor lauter. I've had a lot better luck since I started doing this. Similarly, its better to flow water under the grain bed instead of air/ CO2 when trying to unstick it. Air WILL get trapped under your screen, you may then un-prime your pump and cause said swearing. I've done both and water works much better - just beware of diluting your ratio too much.
3.) Let the grain bed "rest" for about 5 minutes after mashing in. Grain will settle to where it's most beneficial.
4.) Everytime you move a hose, make certain your pump is primed. Turn whatever pump OFF. I find that holding the tubing going into the pump with one hand and holding the one coming out of it with the other and forcibly alternatingly squeezing them for a few seconds will almost always clear an air bubble pretty quickly - even if I don't know if one is there. Then turn pump back ON.
5.). As Kal suggests, turn ON the MLT pump with the MLT inlet valve closed, and slllllooooooowwwwwwlllllllyyyyyy open it. Opening the first third of the valve over a minute or two is the most critical.
6.). One of my best investments was an inexpensive inline sight glass. This will help tell you right away if your sparge is slowing down, or if it never started because your pump has a gas bubble. https://www.ssbrewtech.com/products/micro-sight-glass. $30 is worth your sanity. Use a small LED flashlight to backlight the sightglass and see flow better.
I hope that helps!
|
|
| Back to top |
|
|
rtucker
Joined: 14 May 2016
Posts: 22
Location: Illinois
|
| Link Posted: Tue Jul 18, 2017 1:18 am Post subject: |
|
|
| McGruber wrote: | Are you circulating water through the HERMS coil to heat the mash tun? Is wort reciruculating back into the MLT as you mash in? It sounds to me like your pump isn't primed
|
Yeah, this isn't a priming problem. When I disconnected the hose leading from the kettle the pump I got almost no gravity flow. In fact, after screwing around with it for 10 minutes, that's how I knew it was unstuck. Wort started coming out of the kettle again. I didn't have any problems after that.
| McGruber wrote: |
Some suggestions based on similar problems I've encountered:
1.) Turn off your MLT pump when you mash-in. From experience mashing-in this way and troubleshooting stuck lauters I do think running it makes for a plugged screen.
2.) I've found that it works better to "underlet" the mash screen - which is where you run HLT water into the BOTTOM of the MLT. This forces a surprising amount of air out from under the screen which can contribute to stuck mash/ poor lauter. I've had a lot better luck since I started doing this. Similarly, its better to flow water under the grain bed instead of air/ CO2 when trying to unstick it. Air WILL get trapped under your screen, you may then un-prime your pump and cause said swearing. I've done both and water works much better - just beware of diluting your ratio too much.
3.) Let the grain bed "rest" for about 5 minutes after mashing in. Grain will settle to where it's most beneficial.
4.) Everytime you move a hose, make certain your pump is primed. Turn whatever pump OFF. I find that holding the tubing going into the pump with one hand and holding the one coming out of it with the other and forcibly alternatingly squeezing them for a few seconds will almost always clear an air bubble pretty quickly - even if I don't know if one is there. Then turn pump back ON.
5.). As Kal suggests, turn ON the MLT pump with the MLT inlet valve closed, and slllllooooooowwwwwwlllllllyyyyyy open it. Opening the first third of the valve over a minute or two is the most critical.
|
These suggestions all line up with other threads I've been reading. It sounds like most folks are giving the grain bed 5-10 minutes to settle after dough in, and it seems like the slowest flow you can use and still maintain temperature the better.
_________________
You're not a country unless you have beer
Roger Tucker
|
|
| Back to top |
|
|
McGruber
Joined: 12 Aug 2014
Posts: 237
Location: Idaho
|
| Link Posted: Tue Jul 18, 2017 1:28 am Post subject: |
|
|
| rtucker wrote: | | These suggestions all line up with other threads I've been reading. It sounds like most folks are giving the grain bed 5-10 minutes to settle after dough in, and it seems like the slowest flow you can use and still maintain temperature the better. |
This is true, only I find that I don't really hit the temp I want unless the valve is completely open. I've looked into improving this somehow. No real solution yet.
|
|
| Back to top |
|
|
blazinlow86
Joined: 15 Jan 2017
Posts: 104
Location: vancouver bc
|
| Link Posted: Fri Jul 21, 2017 1:30 am Post subject: |
|
|
|
i had issues until running looser at .055". now its full speed after a few minutes to let the bed settle. i also use rice hulls for anything with wheat in it just to be safe
|
|
| Back to top |
|
|
rattijm
Joined: 25 Nov 2015
Posts: 4
Location: Middletown, OH
|
| Link Posted: Tue Sep 05, 2017 4:16 pm Post subject: Low Flow during Mash |
|
|
Hello all,
New poster here, but long-time watcher. I recently completed my Electric Brewery and have brewed five batches since going operational on 4 Aug 2017. It's essentially a Kal Clone, with a few exceptions as noted in the details below.
Overall I'm very pleased with the setup, but I too have been plagued by flow problems during the mash. I've spent a lot of time troubleshooting (and swearing), and I've made progress but don't yet have a good solution. Here's what I know:
- I have no clogs from husks or other trub in either the MLT drain line or the HERMS coil
- I have no problems getting an initial prime on my pumps
- There are no leaks in the QDs or any of the fittings
- The pumps (Blichmann RipTides) are working great
- My grain mill is set for 0.055" (very coarse)
- I follow Kal's Brew Day Step-by-Step carefully
I went through an extensive troubleshooting session yesterday and the results are documented below - you can read through the detail if you wish. But here's the upshot:
- For some reason my mash compacts to the point that flow is severely restricted after 10-20 minutes
- If I gently stir the mash a bit, flow resumes and things proceed fairly normally after that
- Even so, the flow never really seems to return to the level it was at the beginning of the mash
So I need to figure out why the mash compacts so badly.
I have one possible explanation, but wanted to run it by you guys to get your opinion. I'm using some very old malt as I "play" with my system (probably 3 years old, but stored in airtight containers). The grain is quite dry, but tastes ok and seems to get good conversion. However, I'm wondering if, because it's so dry and hard, am I getting too much fine flour and/or are my husks breaking into too small of pieces despite my 0.055" spacing on the grain mill? If so, I may be getting flour paste clogging my false bottom, and the husks are too small to prevent significant compaction.
I'm planning to run another test using fresh grain (hate to waste the money, but better to do it on a test batch than ruin a "real" batch I guess) to see if that helps, but I wanted to see what you guys thought first.
And for your reading pleasure (or not), here's the diary of my test run yesterday:
System Configuration:
• Using two Blichmann RipTide pumps
• 15 Gal Blichmann pots (G2 for HLT; G1 for MLT and BK)
• MLT has standard Blichmann false bottom
• Pickup on MLT shortened slightly so that it is approx. 3/8” above bottom of tank
o I did this because I originally suspected it might be clogging with husks/gunk
o I can just slip my index fingertip below it
o It is still below the level of the false bottom, but only by a mm or two
• All other parts of setup are Kal Clone
• Barley Crusher grain mill set to 0.055” (was originally at 0.039”)
• Temps calibrated against a Thermapen Mk4
“Test Mash” Details:
• 12.8 Lbs. Pilsner malt crushed to 0.055”, low RPM
• MLT filled to 4.0 gal mark (approx. 1.2 mash ratio after allowing for 0.19 gal under false bottom)
• Mash Temp 122° (simulate 1st step of two-step mash)
• Heated HLT to 130° to “overshoot” and reach 122° mash temp more quickly
Troubleshooting Steps:
• After xfer of strike water to HLT but before adding grain, no flow issues
o All valves wide open
o MLT temp stabilized fairly quickly at 1° below HLT
o Can close drain valve on MLT without causing bubbles or cavitation
o Speed of closing or reopening valve has no effect – still no cavitation or bubbles
o Wiggled, pulled and put side loads on MLT drain QD fitting to rule out any sealing issues – none found
• Before adding grain, removed false bottom and put my finger over the MLT drain pickup
o Flow, of course, decreased/stopped, but no cavitation or bubbles in pump inlet hose
• Reassembled False bottom, pickup and washer per normal setup
• Shut off MLT pump; closed valves on MLT drain, HERMS coil in/out, and MLT inlet
• Left MLT pump outlet valve full open
• Left HLT pump running, heating element on, and HLT pump on, valves full open
• Moved MLT inlet hose out of the way
• Added crushed grain, stirring gently to avoid doughballs
• After adding grain, sight gauge went from 4.0 gal to 5.25 gal
• Allowed to rest for 5 minutes before starting pump
• Replaced MLT inlet hose on top of grain bed
• Opened MLT drain valve, then started MLT pump
• Opened HERMS inlet, HERMS outlet, then MLT inlet, in that order
• All valves full open
• Flow started immediately, no issues
• Sight gauge level began slowly dropping
o Went from 5.2 gal down to 3.5, then stabilized
• After several minutes (did not time exactly), sight gauge began to rise slowly rise and stabilized at ~4.2 gal
• After about 20 minutes, sight gauge began dropping again
o Went as low as 3.25 gal
o Could make it rise by stopping flow temporarily (using HERMS inlet valve), but would again drop to around 3.5
o Over next 20 minutes, oscillated slowly between about 3.5 and 4.0 gal
o No cavitation or bubbles evident but flow seemed weaker
• Then noticed MLT temp started to drop a couple degrees
• Noticed bubbles in MLT pump inlet hose and noticeably lower flow in MLT pump inlet line and in MLT itself
• Left all valves open, but turned off MLT pump for about 30 seconds
o Sight gauge level rose to ~5 gal
• Restarted pump – flow was much stronger, but only for about 10 seconds
o Bubbles and low flow returned
• Shut off MLT pump and closed MLT drain valve
• Used mash paddle to gently loosen grain bed (I know, I know, but had to see what was blocking flow!)
• Closed MLT pump outlet valve and HERMS input valve, removed QD at MLT pump outlet
• Opened MLT pump outlet and let wort gravity flow from MLT – good flow, no issues
o Drained about 1 liter and poured it back into MLT
• Reconfigured all and restarted MLT pump
o Good, strong flow, but very milky, as expected for disturbing grain bed
• Raised HLT temp to 155° simulate starting 2nd mash step
• MLT temp began to rise
• But then flow again would occasionally reduce and I’d see bubbles in MLT pump inlet
• Rate of MLT temp rise decreased, but continued to climb
• Bubbles appeared in inlet line occasionally; flow seemed a little low
• Temp rise very slow – took over 25 minutes to go from 122° to 155°
o Needed HLT temp 2° higher than MLT to hold temp
• Flow continued to be ok but not great
• Wort eventually cleared
• Flow better but not great after 60 minutes total
• Raised HLT to 170° for simulated mash out
• Temp rise seemed slow – took 14.5 min to go from 155° to 168°
Any/all advice and comment welcome!
_________________
Jim Ratti
Arbor Pointe Brewery
|
|
| Back to top |
|
|
kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11120
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
|
| Link Posted: Tue Sep 05, 2017 4:59 pm Post subject: Re: Low Flow during Mash |
|
|
Welcome to the forum!
| rattijm wrote: | | I'm using some very old malt as I "play" with my system (probably 3 years old, but stored in airtight containers). The grain is quite dry, but tastes ok and seems to get good conversion. However, I'm wondering if, because it's so dry and hard, am I getting too much fine flour and/or are my husks breaking into too small of pieces despite my 0.055" spacing on the grain mill? |
Got any pictures of it after crush? A perfect crush results in most of the husks remaining intact while the grain inside is cracked into approximately 2-4 pieces:
If you're having issues, one thing I can suggest is to open the mash pump slowly over 60-120 seconds after you dough in. Watch the sight glass: If it starts to drop and doesn't stop dropping, you're getting into stuck mash situation. It's normal for the level to drop maybe 10-20% maybe (and inch or so) but not 50-60%+. If it starts to drop and keeps dropping, stop, re-stir, and try again, opening very slowly, a bit at a time over a minute or two until the MLT pump is fully open.
You shouldn't have to shorten the dip tube in the MLT at all. The gap between the dip tube and the bottom of the kettle is larger than the slit sizes on the false bottom, so anything small that gets through the false bottom will make it all the way back around and be deposited on top of the grain bed and will be caught in the next round or two.
(This is why over time the wort gets clearer - small bits or dust are in circulation and over time they get caught - it can take 20-30-40 mins before the wort runs what appears to be perfectly clear).
The only other unknown I can't comment on are the new Blichmann RipTide pumps as I haven't used them. Be aware that there are issues with the initial run of these pumps with the impellers melting if the wort or water is too hot, but if you're getting flow then that's not an issue (as the pumps lock up and no longer work if the impellers melt/deform).
What I think is the likely culprit: If you're seeing bubbles in the MLT inlet hose, air is getting into the loop somehow which may be the issue - it may be a poorly sealing QD or similar. What may happen is that the pressure builds up due to grain compaction and instead of just working through it all of the sudden the path of least resistance is to suck air from the outside through a defective QD (or similar) instead of pulling through the grain bed. I've heard of at least one case where someone had poor QDs that were not mating properly and wouldn't leak or cause issues with water, but as soon as any back-pressure was applied through the grain bed they were getting air.
Cheers!
Kal
_________________
Our new shop with over 150 new products: shop.TheElectricBrewery.com
We ship worldwide and support our products and customers for life.
Purchasing through our affiliate links helps support our site at no extra cost to you. We thank you!
My basement/bar/brewery build 2.0
|
|
| Back to top |
|
|
McGruber
Joined: 12 Aug 2014
Posts: 237
Location: Idaho
|
| Link Posted: Tue Sep 05, 2017 5:20 pm Post subject: Re: Low Flow during Mash |
|
|
Hey rattijm. Welcome to the forum. You've nicely detailed your setup and process. Here's my two cents.
| rattijm wrote: | | I have one possible explanation...I'm using some very old malt...because it's so dry and hard, am I getting too much fine flour and/or are my husks breaking into too small of pieces despite my 0.055" spacing on the grain mill? If so, I may be getting flour paste clogging my false bottom, and the husks are too small to prevent significant compaction. |
This is a very real possibility. A way to check and still use the grain you have would be to "condition" your grain before you mill. I use a small water spray bottle and slightly dampen the malt. After weighing out all the grain I put it in a portable igloo cooler and spray and mix by hand until it feels just slightly damp. Be careful not to over dampen it though - I had an unpleasant experience on my first go around when I got all the grain quite wet and the mill just turned everything into paste and kept jamming up. Conditioning will help retain better husk, but won't help much if the inside of the grain is way too dry. I believe standard moisture content of grain is about 4%, and if it's zero in your case, that could be part of your problem (flour).
| rattijm wrote: | System Configuration:
• Using two Blichmann RipTide pumps
• 15 Gal Blichmann pots (G2 for HLT; G1 for MLT and BK)
• MLT has standard Blichmann false bottom
• Pickup on MLT shortened slightly so that it is approx. 3/8” above bottom of tank |
My thought on this was that I have no idea how hard the RipTide pump pulls vs my March SS head pump. It's possible that you might not want to open the valve all the way. I find that my MLT won't hold the right temp unless the valve is fully open, but in your case you might just be pulling too hard on the grain bed. If your MLT temp is stable with the valve open half way, then I'd just leave it there. It's kind of counter-intutive, but in a mash tun flow resistance increases as pressure increases (the harder the pump sucks, the more resistance to flow there will be). If your flow (MLT temp) is fine at lower suction, then stick with that.
| rattijm wrote: |
o Speed of closing or reopening valve has no effect – still no cavitation or bubbles |
In all cases, always open the MLT inlet as slowly as you possibly can. Opening fast will instantly compact the bottom layer and lead to headaches.
| rattijm wrote: |
• Used mash paddle to gently loosen grain bed (I know, I know, but had to see what was blocking flow!) |
Don't feel bad about this. Many professional breweries mix the mash continuously. Just let it sit undisturbed as long as possible to help it clarify. If it's running fine then there's no need to mix it. If it's stuck. Mix it!
| rattijm wrote: |
"Mash Temp 122'F Raised to 155'F " |
For me this is a very low temperature. My personal opinion is that there's no need for a protein rest, especially at that low of a temperature - 140' range is usually my lowest point. At that temp you're beginning to break down proteins and gelatinize starches, but at that low of temperature it's going to gelatinize but not flow well through the bed (malt sugar pudding). Going back to flow resistance, increase in thickness also negatively impacts flow. My flow always gets better as temperature increases to mash-out temp. If you shoot for higher temperatures, flow should improve. (*This is also dependent on starch conversion, but if you don't hit the right enzyme ranges then sugar molecule size will also not decrease)
So in summary,
1.) Condition the malt to better retain husk
2.) Open MLT valve as slow as possible
3.) Try running your valve half open
4.) Increase mash-in temp
Otherwise you could bump your mill to higher gap widths and just track your efficiency, and/or use rice hulls with your old grain until you get fresh grain. Your process looks sound to me though. Good luck!
|
|
| Back to top |
|
|
rattijm
Joined: 25 Nov 2015
Posts: 4
Location: Middletown, OH
|
| Link Posted: Tue Sep 05, 2017 8:14 pm Post subject: Re: Low Flow during Mash |
|
|
McGruber,
Thanks for your quick and thorough response. Very helpful! Replies/comments inserted below:
| McGruber wrote: | | Hey rattijm. Welcome to the forum. You've nicely detailed your setup and process. Here's my two cents. |
Thanks! Happy to be here.
| McGruber wrote: | | This is a very real possibility. A way to check and still use the grain you have would be to "condition" your grain before you mill. I use a small water spray bottle and slightly dampen the malt. After weighing out all the grain I put it in a portable igloo cooler and spray and mix by hand until it feels just slightly damp. Be careful not to over dampen it though - I had an unpleasant experience on my first go around when I got all the grain quite wet and the mill just turned everything into paste and kept jamming up. Conditioning will help retain better husk, but won't help much if the inside of the grain is way too dry. I believe standard moisture content of grain is about 4%, and if it's zero in your case, that could be part of your problem (flour). |
Thanks for that tip (conditioning). I'll give it a whirl, as my husks are considerably more broken up than in the picture Kal posted in his response above. Looks like I've got more flour too.
| McGruber wrote: | | My thought on this was that I have no idea how hard the RipTide pump pulls vs my March SS head pump. It's possible that you might not want to open the valve all the way. I find that my MLT won't hold the right temp unless the valve is fully open, but in your case you might just be pulling too hard on the grain bed. If your MLT temp is stable with the valve open half way, then I'd just leave it there. It's kind of counter-intutive, but in a mash tun flow resistance increases as pressure increases (the harder the pump sucks, the more resistance to flow there will be). If your flow (MLT temp) is fine at lower suction, then stick with that. |
I think the RipTide pulls really hard, so what you say makes a lot of sense to me. I'll try the flow reduction, but am a bit concerned that I'll have temp issues without full flow. I think my bigger problem is opening the valve too quickly and pulling down my gummy mash... If I can "un-gummy" the mash and be a little more careful about not suddenly starting the flow, I think the high suction of the pump will be less of an issue. In any case, more experimentation to follow!
| McGruber wrote: |
Don't feel bad about this. Many professional breweries mix the mash continuously. Just let it sit undisturbed as long as possible to help it clarify. If it's running fine then there's no need to mix it. If it's stuck. Mix it! |
Yeah, I think this is the final answer if all the other techniques fail and I still end up with stuck/reduced flow.
| McGruber wrote: |
For me this is a very low temperature. My personal opinion is that there's no need for a protein rest, especially at that low of a temperature - 140' range is usually my lowest point. |
Hmm... I have several recipes with low-temp (~122°-130°) protein rests. I don't have enough experience yet to fully judge, but I've not had issues before using those temps. However, this is my first run at HERMS brewing, so my prior experience doesn't translate well here. I'll have to work with the other techniques and see how I make out before giving up on the low-temp Protein rests.
| McGruber wrote: |
So in summary,
1.) Condition the malt to better retain husk
2.) Open MLT valve as slow as possible
3.) Try running your valve half open
4.) Increase mash-in temp |
All good tips, which I'll try in future batches/test runs!
| McGruber wrote: |
Otherwise you could bump your mill to higher gap widths and just track your efficiency, and/or use rice hulls with your old grain until you get fresh grain. |
Gap is already pretty wide at 0.55". But conditioning as you suggested above, and adding rice hulls, might get me through my old grain.
Again, thanks for your thoughtful replies - very helpful!
_________________
Jim Ratti
Arbor Pointe Brewery
|
|
| Back to top |
|
|
kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11120
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
|
|
| Back to top |
|
|
rattijm
Joined: 25 Nov 2015
Posts: 4
Location: Middletown, OH
|
| Link Posted: Tue Sep 05, 2017 8:41 pm Post subject: Re: Low Flow during Mash |
|
|
| kal wrote: | | Welcome to the forum! |
Thanks! Good to be here and to finally have my setup in operation.
| kal wrote: | | Got any pictures of it after crush? A perfect crush results in most of the husks remaining intact while the grain inside is cracked into approximately 2-4 pieces. |
I can post a picture later, but can tell you that my husks appear more broken up than in your picture. I also have more flour. I'm using a wide (0.055") gap and low rpm, but I think the grain is just too dry. McGruber suggested conditioning the grain before the crush, and that makes sense to me. I'll give it a whirl in a future experiment.
| kal wrote: | | If you're having issues, one thing I can suggest is to open the mash pump slowly over 60-120 seconds after you dough in. Watch the sight glass: If it starts to drop and doesn't stop dropping, you're getting into stuck mash situation. It's normal for the level to drop maybe 10-20% maybe (and inch or so) but not 50-60%+. If it starts to drop and keeps dropping, stop, re-stir, and try again, opening very slowly, a bit at a time over a minute or two until the MLT pump is fully open. |
Excellent tip, and this will be part of my technique going forward.
| kal wrote: | | You shouldn't have to shorten the dip tube in the MLT at all. The gap between the dip tube and the bottom of the kettle is larger than the slit sizes on the false bottom, so anything small that gets through the false bottom will make it all the way back around and be deposited on top of the grain bed and will be caught in the next round or two. |
Yeah, I realized this after I did it, once I figured out that no significant trub was getting through my false bottom. But, it was one of the first things I thought of, before I realized how much the mash was compacting and how hard it was to get flow through it. It's not a biggie since the MLT doesn't have to fully drain anyway.
| kal wrote: | | The only other unknown I can't comment on are the new Blichmann RipTide pumps as I haven't used them. Be aware that there are issues with the initial run of these pumps with the impellers melting if the wort or water is too hot, but if you're getting flow then that's not an issue (as the pumps lock up and no longer work if the impellers melt/deform). |
I was unaware of the early impeller issues, but I think I'm out of the woods on that - I've run wort straight out of the boil kettle at 205°-209° without problems. Overall the pumps work very well and have superb flow. If anything, they might pull too hard (see McGruber's post).
| kal wrote: | | What I think is the likely culprit: If you're seeing bubbles in the MLT inlet hose, air is getting into the loop somehow which may be the issue - it may be a poorly sealing QD or similar. What may happen is that the pressure builds up due to grain compaction and instead of just working through it all of the sudden the path of least resistance is to suck air from the outside through a defective QD (or similar) instead of pulling through the grain bed. I've heard of at least one case where someone had poor QDs that were not mating properly and wouldn't leak or cause issues with water, but as soon as any back-pressure was applied through the grain bed they were getting air. |
I'm firmly convinced there are no leaks. I did have issues with some QDs I got from Northern Brewer - they fit loosely and leaked under very slight movement of the fittings and under low pressure. I replaced them with QDs from AIB and the difference was remarkable. In fact, some of them are so snug I have to really put some muscle on them to attach/detach when they're hot and the O-rings are expanded. I've blocked the flow through the dip tube with my fingertip while putting some serious push/pull/sideloads on the fittings and seen no bubbles at all under full suction from the pump. But, that's at low temps (I needed to get my hand in the water to try it!).
What I really believe is happening is cavitation. Cavitation occurs when the liquid "boils" in the line, and vapor trapped in the liquid escapes even though the temp is below the normal boiling point. It's exacerbated by the heat of the mash and the lower pressure caused by the suction of the pump. But vapor is vapor, and once it's in the pump inlet it breaks the prime and the flow goes to nil. So the trick for me is to unstick the mash and get the flow going, reducing the negative pressure in the pump inlet line, stopping the cavitation.
In summary, both you and McGruber have given me several good ideas to try. Back to the brew room...
Cheers to all,
_________________
Jim Ratti
Arbor Pointe Brewery
|
|
| Back to top |
|
|
kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11120
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
|
| Link Posted: Tue Sep 05, 2017 8:50 pm Post subject: Re: Low Flow during Mash |
|
|
| rattijm wrote: | | kal wrote: | | Got any pictures of it after crush? A perfect crush results in most of the husks remaining intact while the grain inside is cracked into approximately 2-4 pieces. |
I can post a picture later, but can tell you that my husks appear more broken up than in your picture. I also have more flour. I'm using a wide (0.055") gap and low rpm, but I think the grain is just too dry. McGruber suggested conditioning the grain before the crush, and that makes sense to me. I'll give it a whirl in a future experiment. |
Please do! That sounds like a good plan. My mill was set to 0.045" in the above picture and if you're getting a lot more flour and shredding at 0.055" then your guess that it's probably too dry may be right on the money. Now that said, I may be wrong but I always thought that grain picked up moisture from the air over time, not the other way around (maybe the grain was somewhere extremely dry?)
| rattijm wrote: | | Yeah, I realized this after I did it, once I figured out that no significant trub was getting through my false bottom. But, it was one of the first things I thought of, before I realized how much the mash was compacting and how hard it was to get flow through it. It's not a biggie since the MLT doesn't have to fully drain anyway. |
Yup. If you're bothered by leaving behind some sweet wort, you can always swap the MLT and HLT dip tubes. Then all you'll leave behind is slightly more water in the HLT. (Less precious than sweet wort). 
Let us know how you make out...
Kal
_________________
Our new shop with over 150 new products: shop.TheElectricBrewery.com
We ship worldwide and support our products and customers for life.
Purchasing through our affiliate links helps support our site at no extra cost to you. We thank you!
My basement/bar/brewery build 2.0
|
|
| Back to top |
|
|
McGruber
Joined: 12 Aug 2014
Posts: 237
Location: Idaho
|
| Link Posted: Tue Sep 05, 2017 10:06 pm Post subject: Re: Low Flow during Mash |
|
|
| rattijm wrote: | | What I really believe is happening is cavitation. Cavitation occurs when the liquid "boils" in the line, and vapor trapped in the liquid escapes even though the temp is below the normal boiling point. It's exacerbated by the heat of the mash and the lower pressure caused by the suction of the pump. But vapor is vapor, and once it's in the pump inlet it breaks the prime and the flow goes to nil. So the trick for me is to unstick the mash and get the flow going, reducing the negative pressure in the pump inlet line, stopping the cavitation. |
I strongly agree with this statement. I have pro-grade tri-clamp fittings, and redid my connections/ hardware on the MLT twice. I still occasionally have this problem and it always coincides with a dropping sight glass and temperature drop (low flow). No way air is getting in there. I'm sure some of the QD fittings for some people are faulty, but I think cavitation from a stuck mash is the likely culprit most of the time it has been mentioned.
Now I keep a few pounds of rice hulls on hand just in case my mash seems to be sticking. I'd rather be able to mix in a few handfuls as needed then spend hours troubleshooting the MLT. (Pumpkin beer coming up...learned from experience).
|
|
| Back to top |
|
|
rattijm
Joined: 25 Nov 2015
Posts: 4
Location: Middletown, OH
|
| Link Posted: Sat Sep 16, 2017 7:09 pm Post subject: Re: Low Flow During Mash |
|
|
Well, I don't know if it was the fresh malt, the coarse 0.050" crush, the 0.5 Lbs of rice hulls I added, or the classical music I played throughout the brew, but I made a batch of Irish Red Ale today without ANY drama! Yay! I had good, strong flow during the mash right from the very start, and was able to hold the 152° mash temp without any difficulty. I only needed to set the HLT 1° than the desired mash temp to hold 152° rock solid. I was able to run both pumps wide open throughout.
I followed the advice of McGruber and Kal, starting the mash slowly, and working up to full flow over about a 2-3 minute timeframe. Didn't have to stir the mash at all.
I noticed that the crush with the fresh grain I used for this batch resulted in larger, more intact husks than I had with my old, stale grain. There also seemed to be less flour. So, I probably could have done without the rice hulls, but I figured better safe than sorry.
Anyway, I wanted you all to know that things worked out great, and I now (after 6 batches and one test-run) seem to have found the groove.
_________________
Jim Ratti
Arbor Pointe Brewery
|
|
| Back to top |
|
|
kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11120
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
|
|
| Back to top |
|
|
McGruber
Joined: 12 Aug 2014
Posts: 237
Location: Idaho
|
| Link Posted: Wed Sep 20, 2017 1:23 am Post subject: Re: Low Flow During Mash |
|
|
| rattijm wrote: | | I noticed that the crush with the fresh grain I used for this batch resulted in larger, more intact husks than I had with my old, stale grain. There also seemed to be less flour. So, I probably could have done without the rice hulls, but I figured better safe than sorry. |
Glad it worked out for you! If you try conditioning the grain, you might not even need the 1/2 lb of rice hulls (which theoretically add to tannin extraction). Let us know if you try it out, but I'm glad your process is going smoother. I know what that frustration is like.
|
|
| Back to top |
|
|
|
|
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Forum powered by phpBB © phpBB Group
|
|
Log in
Register
User Control Panel
Private Messages
Club Memberships
Search
Memberlist
Photo Albums
Forum FAQ
