Stirring Mash While Recirculating

[Jeremy W]

Question for those out there that continuously recirculate their mash through a HERMS or RIMS setup. Do you still stir your mash every 15 minutes or so?

Reason for the question:
I've typically paused recirculation every 15 minutes or so to do a quick stir, then restart the pump. Two brews ago (a hefeweizen), I got distracted during the mash and didn't stir at all, and still hit my numbers pretty much bang on. On my last brew (yesterday, a NEIPA) I tried the "no stir" method again and missed my pre-boil gravity by a couple of points. I have to wonder if I might be able to get away not stirring on some brews, but for something like an NEIPA, with a bunch of flaked oats, maybe I got more channeling through the mash due to the gumminess of the grain bed or something.

Anyway, curious what others are doing during their recirculating mash.

Cheers!

 

[Sammy86]

I pause and stir at the 30 minute mark and before sparging.

 

[TheMadKing]

Question for those out there that continuously recirculate their mash through a HERMS or RIMS setup. Do you still stir your mash every 15 minutes or so?

Reason for the question:
I've typically paused recirculation every 15 minutes or so to do a quick stir, then restart the pump. Two brews ago (a hefeweizen), I got distracted during the mash and didn't stir at all, and still hit my numbers pretty much bang on. On my last brew (yesterday, a NEIPA) I tried the "no stir" method again and missed my pre-boil gravity by a couple of points. I have to wonder if I might be able to get away not stirring on some brews, but for something like an NEIPA, with a bunch of flaked oats, maybe I got more channeling through the mash due to the gumminess of the grain bed or something.

Anyway, curious what others are doing during their recirculating mash.

Cheers!

I think you're right that it's just a matter of how much channeling you end up getting due to your flow rates and grist composition.

I generally stir every 15 min as well and let the grain bed reset before recirculating again. I also recirculate at a trickle to minimize channeling

 

[Jtvann]

No stirring at all for me. I try to just be consistent with whatever I do and not chase efficiency numbers. Stirring might gain some points, but I’m satisfied with what I get and it’s repeatable.

 

[day_trippr]

I fly sparge on a 20 gallon 3v2p single tier herms rig. I underlet the strike, let everything sit for a couple of minutes, then give the mash one good stir, lid it again and let it sit for maybe five minutes, then start the recirculation pump and slowly ramp up to 2-3 gpm. Stirring the mash again is contraindicated, so that one stir is it for the brew day...

Cheers!

 

[sibelman]

Contraindicated because...? (I too only stir before recirculation begins)

 

[day_trippr]

Because I spent all that recirculation time making a nice grain bed/filter yielding clear wort!

Cheers!

 

[seatazzz]

My last brew (a blonde) I didn't stir at all after the initial dough-in, and I recirculate (side note; that word is damn hard to type) through most of the mash. I got super-clear wort out of it and good SG. I have done batches where I stirred a few times, and I think the wort comes out cloudier; I do MIAB and mill my grain very fine. If I keep the recirculation rate down, I don't get channeling, and wind up with super clear wort and hit my numbers pretty much. Also I'm lazy; and setting a timer every fifteen minutes, getting up from my comfy chair to turn off the pump and stir the mash, might interrupt my time on HBT.

 

[Bobby_M]

Stirring disrupts the grain bed which could actually cause more compaction than leaving it alone. Raking the top couple inches is a different thing, which can prevent channeling.

 

[Bassman2003]

I think paying attention to your mill gap is important if you recirc. A larger gap is most likely better as you will get more distribution, sort of like the role of rice hulls. I also agree that getting the stirring out of the way before the recirc makes sense for clear wort. A slow sparge runoff helps as well.

 

[Vale71]

Contraindicated because...? (I too only stir before recirculation begins)

Cloudier wort.

You can't control temperature if you're not recirculating while waiting for the grain bed to settle again. Depending on whether your tun is insulated or not this could cause some temperature drift.

 

[micraftbeer]

I use a BrewCommander with the mash schedule programmed in and set the timer for it to come on and hear the water to strike temperature early in the morning. I set my alarm clock to get out of bed and mash in, make everything is stirred up really well and no dough balls, then I let the controller do it's thing with mash schedule while I go back to bed. I continually recirculate with my pump through a RIMS. I meet my mash tun again after my alarm goes off again that my mash is done and it's time to sparge.

This starting early in the morning is simply awesome, and I can get so many more brew days done this way when I'm all done at lunch time. If I had to sit the mash even once, this process wouldn't work and my brew days would take up a greater portion of my <awake> day.

 

[TheMadKing]

Cloudier wort.

You can't control temperature if you're not recirculating while waiting for the grain bed to settle again. Depending on whether your tun is insulated or not this could cause some temperature drift.

Do you have any insight as to how much effect, if any, a small amount of temperature drift during the mash actually has on your wort profile and/or finished beer? I have this issue but I have been subscribing to the law of averages when it comes to mash temps. I'm probably not creating mathematically precise sugar profiles in my wort, but I tend to think that that any variations due to temperature drift are within the margin of error of human senses

 

[micraftbeer]

My thinking on recirculation is mainly about consistency/controllability. Now you obviously could argue if you're being consistent within the range of acceptability, who really cares... But my thought with constant recirculation with RIMS is if I want 148F mash (for real or bias-induced-perception differences in the finished beer), I don't have variables like a bigger grain bill or different batch size affecting that mean temperature as much over the ~1 hour mash. Plus I frequently do step mashes, so I obviously need the recirc/RIMS to be effective for that. And if for whatever reason my strike water calculation plus grain temperature wasn't spot on, I can count on being able to adjust in to the desired mash temp and not dork around with grabbing some boiling water or ice cubes to try to adjust.

 

[Genuine]

I usually stir mine halfway through the mash or when I see it go clear. Once it clears up again, it's about time to drain to the kettle for the boil.

 

[Oleson M.D.]

Never stir the mash after dough in is complete. Unless you like cloudy wort!
Re-circulation will take care of any issues, and the temps will average out through the grain bed. You have to get the flow volume set correctly. The "Goldilocks" area...not too fast, not too slow, just right.

 

[ScrewyBrewer]

I intermittently use a long handle whisk to stir the mash as it is recirculating but disagree that creates cloudy wort. Below are pictures of an Amber Ale that I brewed on August 21, 2021.

 

[Hwk-I-St8]

I'm still working out the process on my newly built K-RIMS rig, but so far my process is to underlet, stir/check for dough balls, settle for 5 mins, vorlauf (recirc directly back to mash tun), the do full recirc through the kettle. I have a chapman thermobarrel so my temps don't change much during the rest or vorlauf.

So far this seems to work very well.

Question on recirc rate....what's a good flow rate and how do you measure it?

 

[Jtvann]

I'm still working out the process on my newly built K-RIMS rig, but so far my process is to underlet, stir/check for dough balls, settle for 5 mins, vorlauf (recirc directly back to mash tun), the do full recirc through the kettle. I have a chapman thermobarrel so my temps don't change much during the rest or vorlauf.

So far this seems to work very well.

Question on recirc rate....what's a good flow rate and how do you measure it?

Back when I was measuring it (I don’t anymore) I aimed for 1.5 gallons per minute. I tried various means to measure from simple to more complex. Easiest was to just get a quart mason jar and put my recirculation line in it. Time it for a minute and do the math. Most complex was plumbing a rotameter in line into my system. It worked great, gave a visual on flow rate through the whole process and I really liked it. I think I spent about 40-50 dollars on it. After a few uses I noticed the plastic coupler on it was warping slightly. It wasn’t designed for the heat. I’ve still got it but don’t use it anymore. It still works and doesn’t leak. I just visually didn’t like it and it was one more moving part adding to complexity that ultimately I just didn’t need.

My advise is to set to a rate slow enough that won’t compact your grain bed. Go fast enough to maintain your temps and be able to ramp up to mash out or step temps without taking forever. Somewhere in that window is fine. That window is grain bill specific though. Rice hulls help.

 

[Jtvann]

I guess I do still sorta measure. I use a Ssbrewtech mash tun that has a manometer. I set to rate rate that doesn’t pull suction. If liquid is dropping in the tube from under the false bottom in relation to the one above it, I’m going too fast.

 

[day_trippr]

I have sight gauges on all 3 of my 20g kettles and I do exactly the same - use the mlt sight gauge to set the recirculation rate. I find the rate where the level starts to drop then back off a bit, check a few times over the next minute, and adjust as necessary 'til it's stable. At that point it always putts along without further messing about for the entire mash. I usually end up between 2 and 3 gpm.

I had been thinking about adding one of those flow meters but all the ones I looked at were rated for below 180°F. There would be times the temperature could get close to that (end of sparge) so I passed. I wonder if there are metal and glass versions?

Cheers!

 

[Jtvann]

I have sight gauges on all 3 of my 20g kettles and I do exactly the same - use the mlt sight gauge to set the recirculation rate. I find the rate where the level starts to drop then back off a bit, check a few times over the next minute, and adjust as necessary 'til it's stable. At that point it always putts along without further messing about for the entire mash. I usually end up between 2 and 3 gpm.

I had been thinking about adding one of those flow meters but all the ones I looked at were rated for below 180°F. There would be times the temperature could get close to that (end of sparge) so I passed. I wonder if there are metal and glass versions?

Cheers!

Mine worked great, but it was deforming. Mash out temps are too much for it. Someone doing BIAB would probably be fine.

 

[Dog House Brew]

Underlet my strike, stir, and mash. I don’t stir the mash again.