BIAB Recirc. Issues. Can it be my crush?

[BroomVikin]

I'll start by saying that a very generous HBTer gifted me a Corona mill a few years ago. I let it sit around for quite a while and then just recently decided to give it a try. I cranked the gap down to almost closed, crushed my first batch of grain, and have been getting great efficiency ever since. Think 77%-84%! The catch is this, during recirculation I have serious issues with the wort draining through the grain fast enough to keeping up with the outflow of the kettle. I'm constantly having to stir the mash so I don't run the level below the mash dry. When I say constantly I mean about 15-20 seconds of stirring every 2 minutes or so. As you might guess this gets VERY tiresome over the course of an hour. I have a mini ball valve on the outflow of the pump and it is throttled back almost to closed. So much so that my temp. probe actually reads about 1-1.5 degrees low due to the drastically reduced flow rate. If I open the valve all the way and stir like crazy the probe usually goes up at least a degree. Honestly it's getting really old and I'd like to fix the issue. What I'm wondering is if I'm actually crushing too fine and that the grain is acting more like mud than just a "filter". I've never gotten any off flavors from the crush being too fine (I've read about actually grinding the husks too much being a negative) but I'm starting to wonder if that might be some of my recirculation issues. Thoughts? Ideas?

 

[LittleRiver]

Stop recirculating and the problem will go away.

I get 80%+ efficiency without recirculating, without sparging, and without hassle.

 

[Smellyglove]

A pic of the crush would be helpful. But without any more info I'd say that the crush is a probable culprit. A corona mill tightened down just pulverizes the husks, it doesn't crush, it obliterates the husks. You need more intact husks. And if you loosen the gap to keep more intact husks your efficiency will probably drop if you mash the same as before. Imo a corona-style mill is not optimal for a recirculation mash.

I had the same issue while I was waiting for my lhbs to get a new mill and had to use a huge coffe grinder, which is the same principle as a corona-style-mill. I had to chose between flow or efficiency when recirculating.

 

[BroomVikin]

Stop recirculating and the problem will go away.

I get 80%+ efficiency without recirculating, without sparging, and without hassle.

A) How do you keep consistent mash temps over an hour? Do you measure temperature manually and adjust power to the element?
B) How are you preventing temp stratification w/o stirring or recirculating?

 

[BroomVikin]

A pic of the crush would be helpful. But without any more info I'd say that the crush is a probable culprit. A corona mill tightened down just pulverizes the husks, it doesn't crush, it obliterates the husks. You need more intact husks. And if you loosen the gap to keep more intact husks your efficiency will probably drop if you mash the same as before. Imo a corona-style mill is not optimal for a recirculation mash.

I had the same issue while I was waiting for my lhbs to get a new mill and had to use a huge coffe grinder, which is the same principle as a corona-style-mill. I had to chose between flow or efficiency when recirculating.

I wish I had taken a picture of the crush. I'll try to remember next time. I really don't mind adding an extra half pound of base grains to make up for loss in efficiency if less of a crush will solve the problem. I'm happy to just have my LHBS double crush for me and call it a day if that would fix the problem. I typically only get to brew about every 6 weeks so the extra expense would be minimal.

 

[Smellyglove]

I wish I had taken a picture of the crush. I'll try to remember next time. I really don't mind adding an extra half pound of base grains to make up for loss in efficiency if less of a crush will solve the problem. I'm happy to just have my LHBS double crush for me and call it a day if that would fix the problem. I typically only get to brew about every 6 weeks so the extra expense would be minimal.

Yes that extra malt (and possible extra for the milling at the lhbs) should be your last worries if it gets you through a hassle-free brewday.

 

[RM-MN]

A) How do you keep consistent mash temps over an hour? Do you measure temperature manually and adjust power to the element?
B) How are you preventing temp stratification w/o stirring or recirculating?

A. Why do you care if the temperature drops over the course of an hour. If you set the Corona fine, the conversion will be over before the temperature drops. I've found conversion to be complete in less than 5 minutes with my crush/grind. YMMV. Never stop the mash before 20 minutes, 30 minutes preferred, or you will have beer with alcohol and little flavor. Extracting the flavor takes more time.

B. I stir when I add the grains. That's it. Conversion happens so fast that stratification isn't a problem.

 

[NeoBrew]

I had this same problem with BIAB. I started adding equipment to try to mitigate it. By the time I was done tinkering I was so close to 3 - vessel brewing that I just switched to that.

RM-MN makes a good case for simplicity. If you can just let go of the idea that absolute precision is critical, you will make your brewing and equipment much simpler.

After doing my switch I think I realized what had been causing the problem all along. When you recirculate you MUST keep the flow at the minimum rate that you can get temp control from. When I was doing BIAB I would tend to start the pump full out and then turn it down until I got a nice slow flow. When I switched to 3 vessel I learned that this practice compacts the grain bed in the first few seconds and it's an uphill battle after that. I'm not sure what it is, but once this is done, no amount of stirring seems to get you back to a functional mash.

My advice would be to try on your next mash to start with the pump completely closed and open it only a crack. See how that goes.

 

[azdavid]

Try mixing in a couple handfuls of Rice Hulls to the grain. This will help the grains from compacting to much and should aid in the flow through the bag.

 

[TANSTAAFB]

I used to really stress about recirculating and maintaining mash temps too. I kept adding equipment and ultimately things just got too complicated, it took too long to clean up, and I wasn't really enjoying my brew days. Switched to BIAB and an induction cooktop and won't be going back! RM-MN is right, conversion happens very quickly because the malt we use is highly modified. I hit my mash temps, wrap my kettle with a thick foam exercise mat I picked up cheap, and leave it alone. Depending on what else I'm doing I might pull the bag after 30 minutes or I might go run errands and leave it for a couple of hours. All good!

 

[LittleRiver]

A) How do you keep consistent mash temps over an hour?

I insulate the kettle.

As others have already stated, with a fine crush conversion happens very quickly -- so quickly that insulation is all it takes. I usually mash for 1-2 hours, it varies because I'm usually off doing something else.

Do you measure temperature manually and adjust power to the element?

I use a thermometer with a remote probe so I can monitor the temp without removing the insulation, but in reality I don't usually look at it. I am not worried about a few degrees temperature drop. I usually go do something else like yardwork or run errands during the mash.

Only on one one extremely cold day (I brew in an area of my shop that does not have HVAC) did I have to add a little heat during the mash. I turned the burner on low, and stirred constantly till I got it back to where I wanted it. I did not remove the bag, nor was it damaged.

How are you preventing temp stratification w/o stirring or recirculating?

I stir the grains in thoroughly, insulate the kettle, and go away. Over stressing about temperature stratification does neither me nor the enzymes any good.

There seems to be a pervasive notion among brewers that more complicated systems are somehow inherently "better". It's OK to geek out on hardware if that's what makes you happy. But it doesn't necessarily make better beer, or a better brewing experience.

I really enjoy the elegant simplicity of full volume, no sparge, no squeeze, no recirculation BIAB. It is just so easy and hassle free it's like cheating, and the beer is great!

 

[greyghost]

I use a 1/2 # rice hulls in every brew.

 

[BroomVikin]

Brewed again today and just went with the regular crush from the LHBS. My recirculation was much better but my efficiency dropped from 76-78% down to 64%. Worth it for sure for the reduced headache but I'd sure like to at least be up around 72%.

 

[robcj]

I used to really stress about recirculating and maintaining mash temps too. I kept adding equipment and ultimately things just got too complicated, it took too long to clean up, and I wasn't really enjoying my brew days. Switched to BIAB and an induction cooktop and won't be going back! RM-MN is right, conversion happens very quickly because the malt we use is highly modified. I hit my mash temps, wrap my kettle with a thick foam exercise mat I picked up cheap, and leave it alone. Depending on what else I'm doing I might pull the bag after 30 minutes or I might go run errands and leave it for a couple of hours. All good!

Love it. After years of overcomplicating my process, I recently went back to basics too--just a bag in a kettle on a propane burner. I rarely mash more than 30 minutes and I only boil for 30 minutes too. (Heresy, I know. I won't even get into all the other rules I'm breaking on the cold side of my brew process.) My brew days are shorter, easier and more fun--so I brew more often.

 

[robcj]

I'll start by saying that a very generous HBTer gifted me a Corona mill a few years ago. I let it sit around for quite a while and then just recently decided to give it a try. I cranked the gap down to almost closed, crushed my first batch of grain, and have been getting great efficiency ever since. Think 77%-84%! The catch is this, during recirculation I have serious issues with the wort draining through the grain fast enough to keeping up with the outflow of the kettle. I'm constantly having to stir the mash so I don't run the level below the mash dry. When I say constantly I mean about 15-20 seconds of stirring every 2 minutes or so. As you might guess this gets VERY tiresome over the course of an hour. I have a mini ball valve on the outflow of the pump and it is throttled back almost to closed. So much so that my temp. probe actually reads about 1-1.5 degrees low due to the drastically reduced flow rate. If I open the valve all the way and stir like crazy the probe usually goes up at least a degree. Honestly it's getting really old and I'd like to fix the issue. What I'm wondering is if I'm actually crushing too fine and that the grain is acting more like mud than just a "filter". I've never gotten any off flavors from the crush being too fine (I've read about actually grinding the husks too much being a negative) but I'm starting to wonder if that might be some of my recirculation issues. Thoughts? Ideas?

Crush could certainly affect your recirculation. As others have mentioned, rice hulls could help.

What does your return look like? Do you return the wort to the top of your kettle? Does the return splash down onto the mash or is it somehow inserted into the mash? When I used to recirculate during the mash, I learned it worked best when I used tubing to return the wort to middle or lower third of the mash to rouse the grain into suspension. Otherwise the grain would compact and flow would slow or cease.

Another factor is whether or not you have something like a false bottom, bazooka tube or standoff to keep the bag from getting sucked into your kettle outlet.

I had a pretty cool BIAB RIMS setup but I recently gave up on the additional time and effort that it required. My conversion and attenuation haven't suffered.

 

[BroomVikin]

What does your return look like? Do you return the wort to the top of your kettle? Does the return splash down onto the mash or is it somehow inserted into the mash?

Another factor is whether or not you have something like a false bottom, bazooka tube or standoff to keep the bag from getting sucked into your kettle outlet.

For my return I use the Loc Line Circle Flow kit.

I try to get it just at or under the surface of the wort. I don't think my bag is getting anywhere near the dip tube to clog up the works. I use a false bottom and it's about 3" off the bottom of the kettle.

 

[cooper]

This is great info! I was also struggling with recirculation issues due to crush size etc. my next batch is going to get stirred thoroughly and then get a sleeping bag wrapped around it for an hour and we’ll see how that goes.

 

[PsychoBiter]

Others have had success letting the mash settle for 15 min before you start recirculating. Let the grain bed get situated before you start pulling on it form the bottom with your pump.

Insulate your mash tun and possibly won't need to recirculate depending on outside temps and how big a batch. We only lose a couple degrees over the hour when properly insulated but don't recirculate.

 

[Jeff_T]

I've never recirculated, although for a while I'd been wanting a fancy eBIAB system, but like a few others have mentioned basic BIAB brewing has been outstanding for me and very enjoyable. I too crush super fine, mash in, stir, cover the pot and wrap with a sleeping bag. Come back 30 min - 2hrs later depending on what I've got going on, pull the bag, let it drain while coming up to a boil. It's super simple, makes brewing a fun and easy day and I regularly hit 80% efficiency.

 

[MX1]

Not sure if anyone asked yet, but where did you get your BIAB bag? Do you know the mesh size?
The system I am about to order has a 210 micron mesh bag, seems a bit tight to me, but I will give it a go once or twice.

IIRC the standard is around 300-400 micron, and there are a few vendors here that can hook you up for a good price.

Just a thought

MX1

 

[TANSTAAFB]

Not sure if anyone asked yet, but where did you get your BIAB bag? Do you know the mesh size?
The system I am about to order has a 210 micron mesh bag, seems a bit tight to me, but I will give it a go once or twice.

IIRC the standard is around 300-400 micron, and there are a few vendors here that can hook you up for a good price.

Just a thought

MX1

@wilserbrewer is the way to go!

 

[Yambor44]

Robcj,

I had issues with 2 of my first 3 BIAB's getting stuck on recirculation as well. After some investigating I ordered a 400 micron bag that just came in a couple of days ago. However, my original 210 micron bag is pretty large and flexible and now that you mention this I would bet that was my issue - the bag getting sucked into the outlet. There is no screen of any type there and I did not have my bag secured at the top of the kettle. As long as it was draped over the top sides of the kettle I didn't worry about it.

I'm going to do another recirculating mash with the 210 micron bag and make sure it's secured.

 

[MX1]

Robcj,

I had issues with 2 of my first 3 BIAB's getting stuck on recirculation as well. After some investigating I ordered a 400 micron bag that just came in a couple of days ago. However, my original 210 micron bag is pretty large and flexible and now that you mention this I would bet that was my issue - the bag getting sucked into the outlet. There is no screen of any type there and I did not have my bag secured at the top of the kettle. As long as it was draped over the top sides of the kettle I didn't worry about it.

I'm going to do another recirculating mash with the 210 micron bag and make sure it's secured.

I would like to know the outcome of this, mine will be in a basket, but still the performance of the 210 micron bag has me concerned

MX1

 

[ScrewyBrewer]

When I say constantly I mean about 15-20 seconds of stirring every 2 minutes or so. As you might guess this gets VERY tiresome over the course of an hour.Thoughts? Ideas?

What is the mash thckness?

 

[BroomVikin]

@wilserbrewer is the way to go!

That's what I use. I really like it but it didn't seem to make a difference re: my circulation issues.

 

[BroomVikin]

What is the mash thckness?

I prefer to sparge with about a gallon or so if I can but typically I'm pretty close to a full volume mash.

 

[Yambor44]

I would like to know the outcome of this, mine will be in a basket, but still the performance of the 210 micron bag has me concerned

MX1

As was mine! Don't know where my mind was on that reply! Back to the 400 micron...so glad you posted this.