Help with Mash Recirculation

[pennengr]

Everything went well with today's session (Kolsch on BIAB RIMS with Locline COFI). I did have to lift the bag briefly early on after starting the recirc, but after that everything seemed to equilibrate. Mill set at 0.041. I overshot my preboil gravity by 0.002, mash efficiency around 87% per Beersmith.

 

[Borneogoat]

I have a 15gal Brew Boss with COFI and have had troubles with low efficiency. However, when brewing last weekend I increased my mill gap to 1.25mm (0.049") per earlier posts and hit my target OG for the first time on this system. I WOO-HOO'd so loud the dog ran outside and my GF dropped her Kindle!

Still only have 65% total efficiency according to Beersmith, but at least I can hit my target...

 

[TexasWine]

I have a 15gal Brew Boss with COFI and have had troubles with low efficiency. However, when brewing last weekend I increased my mill gap to 1.25mm (0.049") per earlier posts and hit my target OG for the first time on this system. I WOO-HOO'd so loud the dog ran outside and my GF dropped her Kindle!

Still only have 65% total efficiency according to Beersmith, but at least I can hit my target...

Congrats! I'm assuming that's brew house efficiency you're talking?

Curious, are you measuring your gravity at multiple points in the process? If not, I'd recommend it because that will help identify if your efficiency woes are due to poor conversion or something else.

What was your mill gap set at previously?

 

[Borneogoat]

Congrats! I'm assuming that's brew house efficiency you're talking?

Curious, are you measuring your gravity at multiple points in the process? If not, I'd recommend it because that will help identify if your efficiency woes are due to poor conversion or something else.

What was your mill gap set at previously?

Regarding my 65% efficiency, it is what Beersmith calls "Tot Efficiency". I believe this is the same as Brewhouse Efficiency. I'm taking SG readings post mash and post boil. The post boil was dead on and the post mash was low by 0.001. I can live with that! I would like to improve my total/brewhouse efficiency yet more and am open to suggestions...

My previous mill gaps where 0.9mm (~.035") and smaller, due to recommendations by BIAB brewers at my local HB club. I'm going to stick with 1.25mm gap for now as it seemed to work well. The flow through my COFI looked good too, no overflow at the top probably means good circulation.

 

[doug293cz]

If you want to improve your efficiency, the first thing you have to do is determine if your conversion efficiency is low, your lauter efficiency is low, or both are low. Mash efficiency equals conversion efficiency times lauter efficiency, and BeerSmith will will tell you your mash efficiency if you input your actual pre-boil volume and pre-boil SG. If you don't know where the problem is, you don't know what to fix.

Turns out the maximum SG of the wort in the mash is pretty much a function of only the water to grain ratio. So you can determine the conversion efficiency by dividing your actual mash SG by the maximum SG (from the table here.) You should be able to regularly achieve conversion efficiency of 95% or better. If not you need to mash longer (since you don't want to crush finer.)

After you calculate your conversion efficiency, you calculate your lauter efficiency by dividing your mash efficiency by your conversion efficiency. Lauter efficiency is a function of your sparging process, the grain absorption rate, undrainable MLT volume and grain weight to pre-boil volume ratio. The following chart shows the maximum achievable lauter efficiency assuming 0 undrainable volume, and a variety of grain absorption rates.



If you aren't achieving the lauter efficiencies shown on the chart, you should look at:

• Undrainable volume. Minimizing undrainable volume will increase your lauter efficiency.
• Recirculating more prior to running off. Both for initial run off and sparge run off.

Brewhouse efficiency will be negatively impacted by any losses between the BK and the fermenter (kettle trub losses, hose losses, etc.)

Brew on

 

[TexasWine]

I need to add nothing to Doug's post. Excellent information, as usual.

@doug293cz, I hope you plan to do an HBT article on troubleshooting efficiency issues sometime soon. Either that, or I hope you never get tired of repeating yourself

 

[pretzelb]

I need to add nothing to Doug's post. Excellent information, as usual.

@doug293cz, I hope you plan to do an HBT article on troubleshooting efficiency issues sometime soon. Either that, or I hope you never get tired of repeating yourself

Agreed. It would be nice to have a simple worksheet asking for all the key measurements.

 

[Borneogoat]

So I brewed again this weekend with exactly the same Brew Boss settings, mill gap, and Beersmith calculations/settings, but different recipes. I got slightly confusing results.

Last week:
APA (6kg total grain)
60min mash, 60min boil
Est pre boil OG 1.048, actual 1.049 (close enough)
Est post boil OG 1.059, actual 1.059 (perfect)
Est pre boil volume 7.24gal, actual 7.8gal (+0.56gal)
Est post boil volume 5.5gal, actual 5.8gal (+0.30gal)

Summary: Hit target SGs, but too much water.
Possible correction: Use less strike water, around 0.56gal. However, pre & post boil overage different (-0.26gal). Maybe boil-off rate is lower than BS calculation and should raise factor in BS.

This week:
Belgian "Blond'ish" Ale (5.2kg grain + 0.7kg candi syrup will go into primary)
60min mash, 90min boil
Est pre boil OG 1.043, actual 1.044 (close enough)
Est post boil OG 1.050, actual 1.057 (+0.007)
Est pre boil volume 6.99gal, actual 6.8gal (-0.19gal)
Est post boil volume 5.5gal, actual 5.0gal (-0.5gal)

Summary: Mash SG good, but significantly over on post boil OG. Not enough water.
Possible correction: Need a little more strike water (0.18gal). Pre & post under-volume is different (-0.32gal). Boil-off rate is higher than expected, reduce factor in BS.

Comparison: First brew too much strike water and boil-off rate less than expected, but OG into fermenter good. Second brew not enough strike water and boil-off rate higher than expected, OG into fermenter too high. These results conflict, but are from the same settings. Any idea of what I need to tweak or factor I'm missing???

 

[TexasWine]

So I brewed again this weekend with exactly the same Brew Boss settings, mill gap, and Beersmith calculations/settings, but different recipes. I got slightly confusing results.

Last week:
APA (6kg total grain)
60min mash, 60min boil
Est pre boil OG 1.048, actual 1.049 (close enough)
Est post boil OG 1.059, actual 1.059 (perfect)
Est pre boil volume 7.24gal, actual 7.8gal (+0.56gal)
Est post boil volume 5.5gal, actual 5.8gal (+0.30gal)

Summary: Hit target SGs, but too much water.
Possible correction: Use less strike water, around 0.56gal. However, pre & post boil overage different (-0.26gal). Maybe boil-off rate is lower than BS calculation and should raise factor in BS.

This week:
Belgian "Blond'ish" Ale (5.2kg grain + 0.7kg candi syrup will go into primary)
60min mash, 90min boil
Est pre boil OG 1.043, actual 1.044 (close enough)
Est post boil OG 1.050, actual 1.057 (+0.007)
Est pre boil volume 6.99gal, actual 6.8gal (-0.19gal)
Est post boil volume 5.5gal, actual 5.0gal (-0.5gal)

Summary: Mash SG good, but significantly over on post boil OG. Not enough water.
Possible correction: Need a little more strike water (0.18gal). Pre & post under-volume is different (-0.32gal). Boil-off rate is higher than expected, reduce factor in BS.

Comparison: First brew too much strike water and boil-off rate less than expected, but OG into fermenter good. Second brew not enough strike water and boil-off rate higher than expected, OG into fermenter too high. These results conflict, but are from the same settings. Any idea of what I need to tweak or factor I'm missing???

Did a quick sanity check on your first set of numbers. Something is squirrelly in your calculations. To take 7.8 gallons from a gravity of 1.049 to 1.059 you'd only need to boil off about 1.3 gallons, not the two gallons you measured.

Didn't look at the second brew day numbers, but you might want to double check some things.

 

[Borneogoat]

Did a quick sanity check on your first set of numbers. Something is squirrelly in your calculations. To take 7.8 gallons from a gravity of 1.049 to 1.059 you'd only need to boil off about 1.3 gallons, not the two gallons you measured.

Didn't look at the second brew day numbers, but you might want to double check some things.

Hmmm, good point. Maybe I've recorded something wrong in the heat of the brewing moment.... This will make deciphering things much harder. I'll have to brew again and be very careful with my records next time. Guess its another 5gal of beer in the name of science! [Thank you Science]

 

[rzwahr]

That's fantastic. I have been using a 400 micron basket from Arbor Fab for a year or so and have been really happy with it, but have been thinking about some way to recirculate the mash, especially with automation / a PID likely in my future. I'm pretty sure I am going to copy this exactly.

Are you still happy with it? Anything you would change in retrospect?

E: I am using 25 gallon pots to do 10 or 15 gallon batches although 15 is a tight fit - I'm debating adding a second 25 gallon pot to maybe be able to do up to 1bbl batches, in which case recirculation would be essential.

Hey Jackyl, I'm totally happy with it. Going to the arbor fab basket in addition to changing my mill gap to .047" has completely eliminated any stuck recirc issues I had. I can now run my chugger wide open with my loc-line COFI and literally go take a nap and not have to worry about it. It's shortened my brew day considerably since I don't have to worry about stuck recirc, dry firing my element, etc. and can get some other things done instead of babysitting the mash.

How have your brew days gone so far with the locline COFI?

My next refinement to this system is going to be to get the quick connect fittings for the ingress and egress points on the kettle. Reason is, it's a pain in the ass to disconnect your hose and keep from making a mess. The other thing I'd like to come up with would be a sort of holder or hanger for the kettle lid so when I take it off i have a place to hang it on the side of the kettle or whatever, if that makes sense. I have an infared cooker that has some rib hangers with it and tried hanging those on the side of the kettle and hooking the lid handle onto the hooks, and while it will hold the lid, it is a bit awkward because you have to flip the lid around facing away from the kettle, and the COFI ends up dripping wort all over the place since it is not over the kettle but facing outward over the floor, in addition to condensation from the lid running all over creation. What would be really cool I think would be to have a hinged lid, similar to what you see on a trash bin with a self closing lid. But have it mounted in such a way where you could easily pull the hinge off for cleaning. I don't know how likely it is that I'll be able to pull that off since I don't have any metal fabrication equipment.

To be honest, my system is great at this point and I'm making the best beer I've ever made. I'm just telling you what my "To Tinker" list is

 

[jackyl]

I haven't actually built it yet, still working through some existing beers. I was planning on camlocks though, absolutely. I wonder if another camlock on the bottom that disconnects the locline from the kettle top would work for your drip issue. May do that too.

 

[swimIan]

Hey all. Any thoughts on adapting the blichmann autosparge to be used with locline instead of the included hose and COFI filter style?

 

[stever1000]

Lots of great information here... I think I will try a similar COFI arm in my kettle and see if this helps reduce my stuck recirculation.

Does anyone have pictures of their crushed grain at 0.040"? I crush at 0.039" and there is still a lot of fine particles, causing my re circulation to get stuck and starve my pump

 

[Borneogoat]

Lots of great information here... I think I will try a similar COFI arm in my kettle and see if this helps reduce my stuck recirculation.

Does anyone have pictures of their crushed grain at 0.040"? I crush at 0.039" and there is still a lot of fine particles, causing my re circulation to get stuck and starve my pump

I had poor efficiency with my 15gal COFI system. Not stuck recirc, but looked close to stuck. I bumped my grain crush to 1.25mm (0.049"), as recommended by others here, and everything improved dramatically. Better efficiency (+8%), circulation looks good, and improved my mysterious high FG problems. My $0.02 is increase your crushed grain size...

 

[TexasWine]

Lots of great information here... I think I will try a similar COFI arm in my kettle and see if this helps reduce my stuck recirculation.

Does anyone have pictures of their crushed grain at 0.040"? I crush at 0.039" and there is still a lot of fine particles, causing my re circulation to get stuck and starve my pump

Do you condition your grain?

 

[The_Bishop]

The roller gap width doesn't always control the amount of fines generated when crushing grain. If you're using a drill and spinning the mill too fast, you'll shred the husks and create a bunch of flour, too.

For what it's worth, I crush at .038 (three roller mill) at a relatively low speed. When I recirculate, I run wide open on a chugger pump. I also use loc-line through the lid for my return, with one of these on the end of it about 1/4 way deep in the mash aimed to create a whirlpool. Haven't had a stuck recirculation yet, knock on wood.

 

[GregKelley]

Do you condition your grain?

What do you mean by "condition your grain"?

 

[GregKelley]

The roller gap width doesn't always control the amount of fines generated when crushing grain. If you're using a drill and spinning the mill too fast, you'll shred the husks and create a bunch of flour, too.

For what it's worth, I crush at .038 (three roller mill) at a relatively low speed. When I recirculate, I run wide open on a chugger pump. I also use loc-line through the lid for my return, with one of these on the end of it about 1/4 way deep in the mash aimed to create a whirlpool. Haven't had a stuck recirculation yet, knock on wood.

I wonder if the diameter of the pot in comparison to the amount of grain has an effect. In fact, I would guess it likely does. The larger the stack of grain is because of either the grain volume or the smaller diameter of the pot, the more likely it is compressed and possibly sticking.

 

[GotPushrods]

...aimed to create a whirlpool. Haven't had a stuck recirculation yet, knock on wood.

The first time I ever mashed on my new rig I did that and got a huge mash cone in the center and channeling around the edges. Extract was terrible but the recirc was amazing. Does your grain bed stay flat??? I aim my return straight across the center near the top to discourage rotation in either direction.

 

[TexasWine]

What do you mean by "condition your grain"?

This: http://braukaiser.com/wiki/index.php?title=Malt_Conditioning

 

[The_Bishop]

I should have added in that I aim it slightly downwards, so it keeps everything in suspension and moving. Prior to recirc, at grain-in, I stir the mash like it owes me money to avoid doughballs.

But no, I haven't had that issue. I'm generally running 80% brewhouse efficiency and 90% mash efficiency when I'm in the 1.050 and lower range. On the dark mild I brewed yesterday, I hit 84% brewhouse and 91% mash efficiency (as beersmith measures it). When I manually do the math on mash extraction, based on grain PPG and liquor volume, I'm at 97% mash extract efficiency with this last brew.

 

[GotPushrods]

I should have added in that I aim it slightly downwards, so it keeps everything in suspension and moving. Prior to recirc, at grain-in, I stir the mash like it owes me money to avoid doughballs.

But no, I haven't had that issue. I'm generally running 80% brewhouse efficiency and 90% mash efficiency when I'm in the 1.050 and lower range. On the dark mild I brewed yesterday, I hit 84% brewhouse and 91% mash efficiency (as beersmith measures it). When I manually do the math on mash extraction, based on grain PPG and liquor volume, I'm at 97% mash extract efficiency with this last brew.

Gotta say, I've been brewing for darn near 15 years and it never occurred to me to keep everything in suspension. It's always grain bed, grain bed, grain bed...

I assume the recirc stays cloudy the entire mash? Do you let it settle before transferring to the BK? Does it clear up?

 

[stever1000]

I should have added in that I aim it slightly downwards, so it keeps everything in suspension and moving. Prior to recirc, at grain-in, I stir the mash like it owes me money to avoid doughballs.

But no, I haven't had that issue. I'm generally running 80% brewhouse efficiency and 90% mash efficiency when I'm in the 1.050 and lower range. On the dark mild I brewed yesterday, I hit 84% brewhouse and 91% mash efficiency (as beersmith measures it). When I manually do the math on mash extraction, based on grain PPG and liquor volume, I'm at 97% mash extract efficiency with this last brew.

I did the same thing with my locline (just the blue one) pointing it tangent and it kept the top grain suspended and spinning, can't see how deep the grains are effected though (for my installation)

 

[stever1000]

Do you condition your grain?

Not yet...I read the link you posted and will try 2% water (which works out to be more than 3oz for 11lbs of grain, as mentioned in the article) when I brew tonight...

I misunderstood why it is done, it's to keep the husk intact to aid the filter bed. If I condition the grain but keep my crush at 0.039" I will have larger husks, but won't the kernel still get crushed the same amount?

 

[GregKelley]

I should have added in that I aim it slightly downwards, so it keeps everything in suspension and moving. Prior to recirc, at grain-in, I stir the mash like it owes me money to avoid doughballs.

But no, I haven't had that issue. I'm generally running 80% brewhouse efficiency and 90% mash efficiency when I'm in the 1.050 and lower range. On the dark mild I brewed yesterday, I hit 84% brewhouse and 91% mash efficiency (as beersmith measures it). When I manually do the math on mash extraction, based on grain PPG and liquor volume, I'm at 97% mash extract efficiency with this last brew.

If you aim your return downwards, couldn't that lead to the liquor at the top being cooler than the rest? My return comes to the top and while it causes a whirlpool, it doesn't really disturb the bed below. Maybe I need to.

 

[The_Bishop]

GotPushRods: My system is (currently) single vessle, BIAB using a stainless basket. Believe it or not, after 10-15 minutes of recirculation the wort clears up appreciably. It's not crystal by any means, but just a mild cloudiness. The main mash filtration is the 400 micron basket I'm mashing in. To date it has zero effect on finished beer clarity.

That being said, I can't see why it wouldn't work in a conventional mash. Recirculate the mash, then let it settle a few minutes before vorlauf. Might have to mash a little thinner so everything stays fluid.

I find that the constant motion leads to better conversion efficiency.

 

[The_Bishop]

Greg, I don't aim it straight down, just slightly downward. I generally have the nozzle submerged about an inch below the surface, aimed to create a whirlpool and angled slightly downward so some of the 'push' gets the lower portion of the mash gets moving.

 

[GregKelley]

Greg, I don't aim it straight down, just slightly downward. I generally have the nozzle submerged about an inch below the surface, aimed to create a whirlpool and angled slightly downward so some of the 'push' gets the lower portion of the mash gets moving.

I'd love to see a picture of how you do it

 

[TexasWine]

I find that the constant motion leads to better conversion efficiency.

I wonder if it would also help with temp distribution when doing step mashes.

 

[The_Bishop]

Greg: It would just look like loc-line attached to a lid. I'll see what I can do.

Texas: It most certainly does. I can step mash with no issues whatsoever.

 

[stever1000]

I conditioned the grain, kept the crush at 0.039" on my barley crusher, recirculated through my locline through the lid, and the outcome was great. My pump didn't suck air once!

 

[stever1000]

So I've been thinking about my low conversion efficiency and I am wondering if it has anything to do with my re circulation...

I have a 5500W element below my pizza screen "false bottom" that the PID turns on/off to maintain mash temp (i.e. 148F). Depending on the speed of the pump, only so much volume is being recirculated

I am wondering if because the pump isn't circulating fast enough, that the local enzymes in the wort near the element get denatured and therefore reducemy conversion efficiency. Due to the high power of the element, the wort nearest the element would be much much hotter than the wort my temp probe is reading outside of the pot.


I think my next experiment will be recirculating with no heating and see what happens.

 

[andrewmaixner]

So I've been thinking about my low conversion efficiency and I am wondering if it has anything to do with my re circulation...

I have a 5500W element below my pizza screen "false bottom" that the PID turns on/off to maintain mash temp (i.e. 148F). Depending on the speed of the pump, only so much volume is being recirculated

I am wondering if because the pump isn't circulating fast enough, that the local enzymes in the wort near the element get denatured and therefore reducemy conversion efficiency. Due to the high power of the element, the wort nearest the element would be much much hotter than the wort my temp probe is reading outside of the pot.


I think my next experiment will be recirculating with no heating and see what happens.

I wouldn't think that the element heat is a problem for denaturation. Even when I have not used my re-circulation option (just did a couple good stirs and a 45min mash + 10 min mashout @168), I have had good efficiency.
( my numbers: 5 to 15 gal batches, 5500W, PID controlled, crush .045", RO water + minerals, mashes ranging from 148F to 160F, pull bag and squeeze / pour 1-2 gallons and squeeze again
I have been always hitting at least 70% on high gravity, up to 80 on low gravity. )

 

[stever1000]

I wouldn't think that the element heat is a problem for denaturation. Even when I have not used my re-circulation option (just did a couple good stirs and a 45min mash + 10 min mashout @168), I have had good efficiency.
( my numbers: r to 15 gal batched, 5500W, PID controlled, crush .045", RO water + minerals, mashes ranging from 148F to 160F, pull bag and squeeze / pour 1-2 gallons and squeeze again
I have been always hitting at least 70% on high gravity, up to 80 on low gravity. )

Does your element fire during the mash?

I think this may be the problem, if the enzymes denature above 160F, then there must be a certain percent, near the element, that are being denatured due to the heat from the element...

 

[andrewmaixner]

I keep the controller on for mash temp stabilization. It turns the element on and off at about 20% during the mash.

 

[doug293cz]

So I've been thinking about my low conversion efficiency and I am wondering if it has anything to do with my re circulation...

I have a 5500W element below my pizza screen "false bottom" that the PID turns on/off to maintain mash temp (i.e. 148F). Depending on the speed of the pump, only so much volume is being recirculated

I am wondering if because the pump isn't circulating fast enough, that the local enzymes in the wort near the element get denatured and therefore reducemy conversion efficiency. Due to the high power of the element, the wort nearest the element would be much much hotter than the wort my temp probe is reading outside of the pot.


I think my next experiment will be recirculating with no heating and see what happens.

It's possible to modify your controller so that you can switch to 120V for heating during the mash, which would drop the element power to 1375W max. If the element is overheating the wort locally and denaturing the enzymes, this could help. Let me know if you are interested in how to do this.

Brew on

 

[GregKelley]

So I've been thinking about my low conversion efficiency and I am wondering if it has anything to do with my re circulation...

I have a 5500W element below my pizza screen "false bottom" that the PID turns on/off to maintain mash temp (i.e. 148F). Depending on the speed of the pump, only so much volume is being recirculated

I am wondering if because the pump isn't circulating fast enough, that the local enzymes in the wort near the element get denatured and therefore reducemy conversion efficiency. Due to the high power of the element, the wort nearest the element would be much much hotter than the wort my temp probe is reading outside of the pot.


I think my next experiment will be recirculating with no heating and see what happens.

What is the flow rate on your pump? I have the same setup and I think I'm doing 1-2 gallons per minute. That pulls wort across the element keeping it from heating too much. If you circulate without heating you'll find your temp drops a good amount as it is being pulled through those hoses and pump which are lower in temp.

 

[stever1000]

It's possible to modify your controller so that you can switch to 120V for heating during the mash, which would drop the element power to 1375W max. If the element is overheating the wort locally and denaturing the enzymes, this could help. Let me know if you are interested in how to do this.

Brew on

That would be greatly appreciated and from a technical point of view, it sounds just what I need

 

[stever1000]

What is the flow rate on your pump? I have the same setup and I think I'm doing 1-2 gallons per minute. That pulls wort across the element keeping it from heating too much. If you circulate without heating you'll find your temp drops a good amount as it is being pulled through those hoses and pump which are lower in temp.

I haven't measured my flow rate, but it is the minimum flow I can achieve right before the pump stalls out from the head loss. I will measure it next time I have it connected

My pickup is in the bottom corner of the kettle, so the wort would be drawn through the pump from the bottom of the kettle volume