Recirculating system poll

[Blazinlow86]

Hello all seems to be a pretty standard question from new recirculating users about how to avoid having a stuck/compacted mash after there first use. When i built my system everything i read more or less stated that ideally you want your system to be able to flow at full speed. Like most other users i also had the same issues on my first few runs using my system until adjusting my mill looser and milling A LOT slower. Since then i have been able to run full speed with great results and have not had a flow issue in over 50 batches. I was surprised to see in the responses to this specific question that some people are adjusting there flow to as low as 20% of there pumps max speed to avoid getting a stuck/compacted mash. I am curious what other users experiences are as it seems in those posts that its always the same few members and myself debating it. Thanks


So for clarification the options are

i adjust my grist to my system meaning - you adjust your grist coarser to avoid stuck/compacted/ vacuum mash on your recirculating herms/rims system and run it at full or close to full speeds at the expense of efficiency. and you have it dialed in and working that way. basically you mill looser and pump faster


or

i adjust my system to my grist meaning - you mill finer to get better efficiency/ lhbs mills for you etc and you slow the flow to avoid stuck/compacted/ vacuum mash on your recirculating herms/rims system at the expense of flow rate. and you have it dialed in and working that way. basically you mill tighter and pump slower


or

you dont have a herms or rims recirculating setup


cheers

 

[FunkedOut]

I would think that the actual flow rate is a better figure to compare than what percentage of the pumps flow rate is used.
Half a chugger is still way more flow than a small china special.

That said, I have a small china special and restrict its flow to about 1 qt/min (that's 53% max speed).
I don't recirculate for the entire mash period or have a means to add heat via the recirculation system.
It's just used for vorlauf.

I figure that if the lauter rate should not exceed that figure due to channeling, I wouldn't want to create channels during vorlauf/recirculation.

You guys that are recirculating much faster, are you stirring the mash at the end of the mash, then slowing down the lauter rate?
Or just slowing the rate without a stir?

 

[Blazinlow86]

I would think that the actual flow rate is a better figure to compare than what percentage of the pumps flow rate is used.
Half a chugger is still way more flow than a small china special.

That said, I have a small china special and restrict its flow to about 1 qt/min (that's 53% max speed).
I don't recirculate for the entire mash period or have a means to add heat via the recirculation system.
It's just used for vorlauf.

I figure that if the lauter rate should not exceed that figure due to channeling, I wouldn't want to create channels during vorlauf/recirculation.

You guys that are recirculating much faster, are you stirring the mash at the end of the mash, then slowing down the lauter rate?
Or just slowing the rate without a stir?

Sorry ive attempted to change the title to match the question better but appears i cannot. This question\poll was directed at people using a recirculating herms/rims system specifically. The "adjusting grist to the system" meant you adjust your grist to allow full speed of say a chugger pump WITHOUT any channeling or dropping level in sight glass etc. cheers

 

[brewbama]

What in-line flow meters are homebrewers using to determine flow rate? I found a stainless gate valve for precision control (vs a ball valve).

 

[Blazinlow86]

i think most are just adjusting on the fly according to vacuum on the sight gauge to avoid getting a stuck/compacted grain bed. i imagine the specific flow rate changes from batch to batch depending on how the grain bed set etc. cheers

 

[schematix]

You DO NOT want to run your pump wide open. That's a recipe for a stuck mash unless you have a wimpy pump.

Your crush will be fine around 0.032-0.035". Despite what many people here will claim, you can extract 100% of the sugars using about 0.045" and lower. Once you get to about 0.025" you'll have so much flour it could be difficult. For your first time try 0.035" as a happy medium.

Your recirculate rate should be based on how much the grain bed can handle without compaction. The best way to determine if you are compacting is by using a manometer (basically a sight glass). If there is too much pressure across the grain bed the level drops and flow drop won't be far behind. Another useful tool is the rotameter. It's an inline analog flow meter. Takes the guess work out of the flow rate.

I mash in a 20G Blichmann MLT. I will dough-in by underletting at 1.5 GPM. I will then recirculate the first mash step at 1 GPM to settle the bed (and i'm just holding temp). I will then usually go up to 2 GPM for the subsequent steps and then dial back to 1 GPM for lautering. The tail end of lautering i go down to about 1/2 GPM so i can get the last of the liquid out of the grain.

The only reason you want higher flow rates is so you can heat quicker. You have to turn the whole volume over at least once in order to ramp temps.

 

[Blazinlow86]

You DO NOT want to run your pump wide open. That's a recipe for a stuck mash unless you have a wimpy pump.

Your crush will be fine around 0.032-0.035". Despite what many people here will claim, you can extract 100% of the sugars using about 0.045" and lower. Once you get to about 0.025" you'll have so much flour it could be difficult. For your first time try 0.035" as a happy medium.

Your recirculate rate should be based on how much the grain bed can handle without compaction. The best way to determine if you are compacting is by using a manometer (basically a sight glass). If there is too much pressure across the grain bed the level drops and flow drop won't be far behind. Another useful tool is the rotameter. It's an inline analog flow meter. Takes the guess work out of the flow rate.

I mash in a 20G Blichmann MLT. I will dough-in by underletting at 1.5 GPM. I will then recirculate the first mash step at 1 GPM to settle the bed (and i'm just holding temp). I will then usually go up to 2 GPM for the subsequent steps and then dial back to 1 GPM for lautering. The tail end of lautering i go down to about 1/2 GPM so i can get the last of the liquid out of the grain.

The only reason you want higher flow rates is so you can heat quicker. You have to turn the whole volume over at least once in order to ramp temps.

sorry to clarify the option "adjusting grist to the system" specifically meant you adjust your grist to allow full speed of say a chugger pump WITHOUT any channeling/ stuck mash sparge or dropping level in sight glass. for example i adjust my grist to my system (coarse) allowing me to run full speed WITHOUT any channeling or a stuck mash. At wide open my sight level doesnt drop. cheers






schematix im surprised to hear your Blichmann setup cant run full speed without compacting. that was one of the big things i kept reading when researching my build was to get the blichmann as it specifically could run full speed even with a tighter mill setting and wheat malt. do you have the matching false bottom?

 

[FunkedOut]

I measure flow rate in a very low tech way using a measuring cup (quart) and a wrist watch

 

[schematix]

sorry to clarify the option "adjusting grist to the system" specifically meant you adjust your grist to allow full speed of say a chugger pump WITHOUT any channeling/ stuck mash sparge or dropping level in sight glass. for example i adjust my grist to my system (coarse) allowing me to run full speed WITHOUT any channeling or a stuck mash. At wide open my sight level doesnt drop. cheers

schematix im surprised to hear your Blichmann setup cant run full speed without compacting. that was one of the big things i kept reading when researching my build was to get the blichmann as it specifically could run full speed even with a tighter mill setting and wheat malt. do you have the matching false bottom?

The Blichmann FB itself can flow pretty fast. Without any grain i can recirc at about 7 GPM, which is basically unrestricted. However the FB can't do anything to stop the laws of physics occurring above it.

 

[Blazinlow86]

fair enough like i said i spent alot of time on the theelectricbrewery.com when first building my system and alot of people there bought that setup specifically because it could run full speed (i think kal even had a side note about it in his directions ). cheers

 

[seatazzz]

Following this post. My pump does fine (even though cheapo Amazon) but I've always been told to ramp it down via the ball valve on the tun to avoid stuck mashes. My efficiency has been crap lately so I'm thinking for the next one will let it run full blast. My tun was built from a 16.6g extract barrel, with a quick connect fitting in the lid attached to a PEX pipe "sparge" arm (about 8 inches with holes drilled about 3/4" apart). I also go overboard on filtering, with a bazooka, a fancy false bottom, and a mash bag. Of course I'll let the bed settle for about ten minutes before cranking to full blast.

 

[Ozarks Mountain Brewery]

I have a 3 pot herms similar to a Kal clone and no two brews are identical, you have to adjust something most times, it's the ball valve for recirculation sometimes it's the water or grain ratio depending on the ingredients, flaked grains are the worst but my system never changes

 

[eric19312]

I measure flow rate with rotometer. I mash in 15 gal kettle with NorCal false bottom. Direct fire heat, constant recirc. Chugger pump.

I flow about 1 GPM during mash then slow to 0.3 to 0.5 GPM during lauter.

Crush is moderately coarse.

My grain bed never really compacts. Maybe near the screen but I never get that layer of wort on top of the grain bed. Mostly it just floats. Be interested if others see similar.

 

[ryanj]

I kept my crush at about .035 and dialed back my pump to about 33% power. I'm mashing in an insulated cooler with a domed false bottom. It flows fine as long as I don't try to pump to fast. Realistically, I probably need to dial it back to 20-25% power, because when I go to sparge (which is run at about 5% power), I'm getting some grain particulate coming out. I believe we discussed this in another thread, but I probably have a vacuum bubble in there.

On my next batch I plan to recirculate closer to 20-25% power and see how that does.

 

[Blazinlow86]

I kept my crush at about .035 and dialed back my pump to about 33% power. I'm mashing in an insulated cooler with a domed false bottom. It flows fine as long as I don't try to pump to fast. Realistically, I probably need to dial it back to 20-25% power, because when I go to sparge (which is run at about 5% power), I'm getting some grain particulate coming out. I believe we discussed this in another thread, but I probably have a vacuum bubble in there.

On my next batch I plan to recirculate closer to 20-25% power and see how that does.

I originally used the same type false bottom on my first setup and found I had to be careful not to knock the FB when stirring the mash otherwise I'd get alot of grain under that took alot of manual circulating to clear up. Something to keep in mind if your stirring at any point. Cheers

 

[mabrungard]

Flowrate is not really the parameter that you need to monitor during recirculation. It is the head drawdown that you need to monitor and you adjust the flowrate to limit the drawdown during the mash.

I have a manometer plumbed into the bottom of my tun and I can see what the drawdown is. I limit the drawdown to about the bottom of the grainbed since my manometer would suck air if I drawdown any farther. I suppose I could fashion my manometer with a U-tube, so that I could drawdown farther, but that seems unnecessary. I don't produce stuck mashes when I limit the drawdown to the bottom of the bed.

An important thing about the permeability (ability to pass flow) of the mash...it changes during the mashing period. It briefly has decent permeability that pretty quickly falls as the bed consolidates. I find that permeability is lowest for the first 10 minutes or so. The permeability then increases as the extract is taken out of the grain. I have to continually monitor and adjust my pump discharge valve to keep the drawdown in the right range.

Having a manometer plumbed either under your false bottom or near the bottom of your tun is a very handy tool to enable flow regulation and avoiding stuck mashes. As Schematix points out, running your pump wide open is almost a sure way to incur a stuck mash.

PS: Since you're circulating wort, there should never be a reason to stir your mash. The only time I stir is when I'm doughing in the grain. I turn off the pump during that period.

 

[Ozarks Mountain Brewery]

mines very simple to see, if the drawdown is too much the site glass drops so I have to balance between a certain area on the site glass with my ball valve usually only the first 30 minutes are critical

 

[munkyhead8]

I have a spike brewing MLT and FB, and I've been running my chugger wide open through a 50' HERMS coil, and haven't noticed a drop in level between the MLT surface and the sightglass. Should I still be thinking about turning the pump down some? I've yet to have a stuck sparge with 10+ batches, which have included both wheat and flaked grains.

 

[Blazinlow86]

Flowrate is not really the parameter that you need to monitor during recirculation. It is the head drawdown that you need to monitor and you adjust the flowrate to limit the drawdown during the mash.

I have a manometer plumbed into the bottom of my tun and I can see what the drawdown is. I limit the drawdown to about the bottom of the grainbed since my manometer would suck air if I drawdown any farther. I suppose I could fashion my manometer with a U-tube, so that I could drawdown farther, but that seems unnecessary. I don't produce stuck mashes when I limit the drawdown to the bottom of the bed.

An important thing about the permeability (ability to pass flow) of the mash...it changes during the mashing period. It briefly has decent permeability that pretty quickly falls as the bed consolidates. I find that permeability is lowest for the first 10 minutes or so. The permeability then increases as the extract is taken out of the grain. I have to continually monitor and adjust my pump discharge valve to keep the drawdown in the right range.

Having a manometer plumbed either under your false bottom or near the bottom of your tun is a very handy tool to enable flow regulation and avoiding stuck mashes. As Schematix points out, running your pump wide open is almost a sure way to incur a stuck mash.

PS: Since you're circulating wort, there should never be a reason to stir your mash. The only time I stir is when I'm doughing in the grain. I turn off the pump during that period.

I don't stir my mash at all after doughing in but I don't have any permeability/flow/ head draw down issues. I've noticed other users having issues oftan running the pump at 25% and stir occasionally during the mash to correct the stuck mash. I was just pointing it out to op as his system was problematic and getting grain in the kettle and he may be doing so. Im guessing here too that if you got a bunch of of husks under the false bottom the slower the flow the longer it would take to filter that stuff out. If the flow was really low maybe not at all? To clarify when I say adjusting the grist to the system I meant milling the grain corse SPECIFICALLY to NOT incur a stuck mash when using wide open. Im only mentioning this again as a few people have cautioned that running full flow will likely cause a stuck mash which is inaccurate. Running wide open will only cause a stuck mash *IF* you do not adjust the grist to allow the wide open operation. Not trying to beat a dead horse but the question/poll was specifically asking this question but I think it's getting confused with *if* it's possible to run wide open which I can assure is very possible. Cheers

 

[schematix]

I have a spike brewing MLT and FB, and I've been running my chugger wide open through a 50' HERMS coil, and haven't noticed a drop in level between the MLT surface and the sightglass. Should I still be thinking about turning the pump down some? I've yet to have a stuck sparge with 10+ batches, which have included both wheat and flaked grains.

I'm gonna take a SWAG here and say the reason you can run your pump wide open is because of the restriction from that 50' coil. Your system may not be able to physically flow faster.

When i've used my march pump to recirculate cold water through my Hydra its probably around 1-2 GPM max.

But really what matters is the pressure drop across the grain bed.

 

[Blazinlow86]

I'm gonna take a SWAG here and say the reason you can run your pump wide open is because of the restriction from that 50' coil. Your system may not be able to physically flow faster.

When i've used my march pump to recirculate cold water through my Hydra its probably around 1-2 GPM max.

But really what matters is the pressure drop across the grain bed.

Hmmm it's definitely possible but I don't think it's making that big a difference. I've never actually had a reason to test the flowrate and of course this is not a very specific way of measuring but the flow into the mash tun out of the herms coil is similar to a garden hose. Next brew day I should measure it to be sure. I love attached a picture of a Brown ale if you look closely you can see the stream out of the MLT return line. Cheers

 

[Blazinlow86]

Actually if you look at the sight glass closely you can also see the sight glass has not dropped at all also. Cheers

 

[day_trippr]

fwiw...I run a 3V2P single tier with a trio of 20g G1s and a pair of March 815pls. The mlt has the (awesome) Blichmann FB and their autosparge valve, the hlt has a 50' 1/2" hex from Stainlessbrewing. I do a slow underlet mash-in, full recirculation after a 10 minute rest, then fly sparge. I crush barley at .030, wheat at .025, and only use rice hulls if the wheat is more than 15% of the grist. I never stir the mash.

I typically recirculate at 2-2.5 gpm as that rate usually keeps the entire mash thermally constant (I run the hlt 2~3°F above the target mash temperature) but ultimately I defer to the mlt sight gauge, keeping the level at least a couple of inches above the FB. If it drops below that I'll throttle down a bit more, but I rarely have to go below 2 gpm, even when doing a rather huge imperial stout.

2 gpm is a major throttling of the 815pl - it will easily triple that rate through the silicone tubing, hex and autosparge - when I'm running a cleaning cycle on the rig, at least. Add 25-45 pounds of grain and that ain't happening, but no matter - as long as the rate is high enough to keep the mash at the desired temperature there's no need for more speed...

Cheers!

 

[Blazinlow86]

2 part question. Efficiency aside would anyone prefer to flow slowly rather than quickly if they could flow faster without any side affects? No stuck mashes no channeling etc. Is there any benefit to lower flow rate again besides efficiency? 2nd part would why did you choose a Herms/rims setup.

I would flow faster as I feel turning the liquid over more times is better than less and I went Herms for the temp control more so than Efficiency. I wanted to not use a offset and have only been able to achieve that with the faster turnover.cheers

 

[schematix]

You want to flow as high as you can without causing other problems. The main reason is performance. The quicker you can turn the liquid over, the quicker you can step the wort temps and also the more constant you'll be holding it.

I normally aim for no more than a couple inches of water column pressure drop. That way when i switch to lautering the whole grain bed doesn't come unset when i shut the pump off to move hoses.

 

[Blazinlow86]

I have a spike brewing MLT and FB, and I've been running my chugger wide open through a 50' HERMS coil, and haven't noticed a drop in level between the MLT surface and the sightglass. Should I still be thinking about turning the pump down some? I've yet to have a stuck sparge with 10+ batches, which have included both wheat and flaked grains.

i would say your systems working great, and to only slow the flow if you want to tighten your mill because you wanted better efficiency and at that point you were getting a compacted grain bed/stuck mash or sparge. cheers

 

[Blazinlow86]

You want to flow as high as you can without causing other problems. The main reason is performance. The quicker you can turn the liquid over, the quicker you can step the wort temps and also the more constant you'll be holding it.

I normally aim for no more than a couple inches of water column pressure drop. That way when i switch to lautering the whole grain bed doesn't come unset when i shut the pump off to move hoses.

Agreed 100%. turns out i am not crazy, just much more concerned with temps than efficiency haha. cheers

 

[schematix]

tighter grind does not necessarily mean better efficiency. it's possible to reach maximum extraction with some very course grinds (0.045 for example).

i always get 100% conversion efficiency (i know because i consult the malt data sheets and also monitor gravity during the mash steps). This takes about a 2 hour mash and a series of carefully chosen steps. i don't grind particularly fine.

 

[Blazinlow86]

tighter grind does not necessarily mean better efficiency. it's possible to reach maximum extraction with some very course grinds (0.045 for example).

i always get 100% conversion efficiency (i know because i consult the malt data sheets and also monitor gravity during the mash steps). This takes about a 2 hour mash and a series of carefully chosen steps. i don't grind particularly fine.

I also agree with this. i mill very course closer to .050 so im pretty sure i could get better efficiency but milling this way makes a super easy process. grain in the tun,quick stir, pumps on full, check ph and adjust, come back a hourish later. i prefer not to monitor flow etc and just live with the possibly lower efficiency. i can leave the house and not worry about it if need be. cheers

 

[Bilsch]

tighter grind does not necessarily mean better efficiency. it's possible to reach maximum extraction with some very course grinds (0.045 for example).

I agree with this as well.
Curious though if your stated gap is on a 2 or 3 roll mill because that makes a huge difference in the grind. I mill closer to .050 as well on a 3 roll.

 

[Blazinlow86]

I agree with this as well.
Curious though if your stated gap is on a 2 or 3 roll mill because that makes a huge difference in the grind. I mill closer to .050 as well on a 3 roll.

i use a cheap 2 roller at .050 slowly and condition every time fwiw

 

[schematix]

I also agree with this. i mill very course closer to .050 so im pretty sure i could get better efficiency but milling this way makes a super easy process. grain in the tun,quick stir, pumps on full, check ph and adjust, come back a hourish later. i prefer not to monitor flow etc and just live with the possibly lower efficiency. i can leave the house and not worry about it if need be. cheers

you'd probably get better efficiency from step mashing that just letting it ride at 1 temp for an hour.

I agree with this as well.
Curious though if your stated gap is on a 2 or 3 roll mill because that makes a huge difference in the grind. I mill closer to .050 as well on a 3 roll.

MM3-Pro

 

[Blazinlow86]

you'd probably get better efficiency from step mashing that just letting it ride at 1 temp for an hour.


MM3-Pro

Thanks for the advise I'll keep it in mind. I'm somewhat hesitate to try anything new as the system is so consist now . Cheers

 

[Ozarks Mountain Brewery]

fwiw...I run a 3V2P single tier with a trio of 20g G1s and a pair of March 815pls. The mlt has the (awesome) Blichmann FB and their autosparge valve, the hlt has a 50' 1/2" hex from Stainlessbrewing. I do a slow underlet mash-in, full recirculation after a 10 minute rest, then fly sparge. I crush barley at .030, wheat at .025, and only use rice hulls if the wheat is more than 15% of the grist. I never stir the mash.

I typically recirculate at 2-2.5 gpm as that rate usually keeps the entire mash thermally constant (I run the hlt 2~3°F above the target mash temperature) but ultimately I defer to the mlt sight gauge, keeping the level at least a couple of inches above the FB. If it drops below that I'll throttle down a bit more, but I rarely have to go below 2 gpm, even when doing a rather huge imperial stout.

2 gpm is a major throttling of the 815pl - it will easily triple that rate through the silicone tubing, hex and autosparge - when I'm running a cleaning cycle on the rig, at least. Add 25-45 pounds of grain and that ain't happening, but no matter - as long as the rate is high enough to keep the mash at the desired temperature there's no need for more speed...

Cheers!

how do you mash recirculate through your auto sparge, I can only get mine to flysparge slow, otherwise it bounces

 

[munkyhead8]

you'd probably get better efficiency from step mashing that just letting it ride at 1 temp for an hour.

So far I've only done single infusion, for 60 min on my eHERMS, and the last couple runs have been ~73% efficiency. Think an additional protein rest would give that a bump?

 

[day_trippr]

how do you mash recirculate through your auto sparge, I can only get mine to flysparge slow, otherwise it bounces

I've seen that, usually when I've opened the pump valve too rapidly, but it's easily cured. I calm everything down by throttling the pump back and let the fluid above the mash stop "waving", then slowly bring up the flow rate again. Works every time.

[edit] I should note I have never had that oscillation happen during the sparge, when my flow rate is just 1 quart per minute. When it happens it's always at much higher flow rates.

Cheers!

 

[brewbama]

..... a series of carefully chosen steps. i don't grind particularly fine.

Would those steps look something like this:

 

[schematix]

Would those steps look something like this:


View attachment 580676

That’s one way to do it. I recall that post you copied the notes from. Very good notes to hang onto. That’s a mash scheduled guaranteed to get full conversion of all but the hardest grain.

If you want to start with an abridged version do 146/40, 162/30 and 171/10. Be sure to not to overshoot 162.

 

[eric19312]

how do you mash recirculate through your auto sparge, I can only get mine to flysparge slow, otherwise it bounces

I unscrew the float ball during mash recirc then screw it back on during lauter.

 

[brewbama]

If you want to start with an abridged version do 146/40, 162/30 and 171/10. Be sure to not to overshoot 162.

This is my abridged version (Hochkurz):