Help me troubleshoot - Recirculation, low efficiency, "batch" sparging

[zman_]

Hey guys,

I recently (3 batches ago) upgraded to a new system and have been having a few variable issues with recirculation, efficiency, and other techniques I was hoping the collective expertise of the internet could help me troubleshoot. Before we get started, this is my system:

• 20g kettle, 4x 1.5" TC fittings (2 capped, 1 for a thermometer, one with a dip tube/butterfly valve).
• 300 micron stainless solid-sided mash basket (sits ~3" off the bottom)
• Center inlet chugger pump + soldered 1.5" TC fittings on inlet/outlet
• Detachable whirlpool arm used for mash recirculation and post-boil whirlpool/hop-stand (externally mounted, ~15" long so comes in a few inches above the bottom of the basket (when inserted) or kettle.
• 25' Stainless counterflow chiller
• 1/2" ID silicone tubing, 1.5" butterfly valves, 1.5" TC fittings connecting everything up

With that out of the way, here are the issues that have popped up:

In my most recent batch (designed to be ~11G of a ~8% DIPA, 35# of grain, 39oz of hops), I had planned to reserve ~3.5G of water for a pour-over sparge after pulling the basket out of my mash as I couldn't run a full volume mash due to the amount of grain (I top out around 28-29# for full-volume of heavily hopped beer when shooting for 11G post-boil wort).

Heated my strike water (~14.5 gallons), mashed in, hit my desired temp, broke up dough balls, let things settle down a bit, and turned on the pump (as low as possible) trying to get some recirculation going. I wasn't able to get any sort of recirculation going and resorted to stirring occasionally to try and ensure even conversion/efficient conversion. 15min in I checked my mash pH and it came in a touch low (5.25 measured against 5.3 predicted), but within a reasonable realm. Mashed for 1hr, lifted the basket above the kettle to drain, started heating the collected wort and poured over the 3.5g of reserved water over the top of the grain, letting it drain into the kettle. I checked both first runnings gravity and pre-boil gravity, both of which were low (~1.058 preboil compared to an expected ~1.070). First runnings, sparge, and pre-boil volumes were almost exactly as predicted.

I went through, boiled/added hops/cooled/transfered to fermenters/pitched yeast/etc and everything is happily fermenting away now. OG was low ~1.065 against 1.080 predicted, so this beer will come in much lower in ABV. My main questions/where I hope I can get some help is: Why did my efficiency take such a hit compared to previous batches? And how can I improve my technique to take full advantage of the recirculation ability/etc?. I had previously done 2 other batches on this system, both full volume mashes and hit all of my numbers (temp, volume, pH, gravities) on the nose. I maxed out the system with 28.5# of grain and obtained a comparable OG to using 35# of grain, which is disappointing to say the least - All full-volume batches on this system (And previous systems) have been 70%+ efficient with numbers almost exactly as predicted.

The potential issue points that I've identified from reading/etc are:

• Dough balls/dry spots not efficiently converting. Potential solution: efficient recirculation, more careful stirring/breaking up of dry spots/dough-balls.
• Inefficient recirculation - I wasn't able to get any real movement going. My initial thought is that this is due to the return from my whirlpool being within the grain bed rather than returning on top of it. Potential solution: replace stainless WP arm with silicone hose that sits on top of grain bed (or locline or something similar). Another potential issue: too fine crush - from what I have read, crushing too finely can inhibit your ability to efficiently recirculate. Some places I've seen suggest backing the crush size off pretty significantly and then making up efficiency due to the recirculation.
• Coarse crush - Most places discussing efficiency with BIAB suggest crushing as fine as possible. This conflicts with the information I've seen about improving recirculation and I would appreciate any insight into how to balance these two competing interests.

I apologize that this has turned into more me throwing ideas up and seeing what sticks. Trying to summarize/streamline:

I am hoping to get some advice about how to maintain efficiency in a single vessel BIAB system when attempting to obtain high starting gravities and exceeding my vessel's capacity for a full-volume mash.

Additionally, I am hoping to get some advice on how to improve my recirculation technique as I eventually want to incorporate an outboard RIMS tube (as a precursor to eBIAB) which would rely on being able to efficiently/consistently move wort over the heating element and draw wort from the mash tun/kettle evenly.

Thanks for any/all help! I am currently at work, but if it would be helpful, I can provide more specific recipe information/session information or equipment information when I get home tonight.

 

[pricelessbrewing]

Step 1: Take detailed measurements

Step 2: Use this https://pricelessbrewing.github.io/BiabCalc/#EfficiencyEvaluation to evaluate each efficiency component.

If conversion score is low, check pH, crush, and dough in/recirc isn't thorough enough.

If lauter and/or sparge score is low, recirculation is causing channeling or stratification of the wort.

If brewhouse is lower than mash, then you have kettle losses.

 

[zman_]

Thanks for that link, I use the BIAB calculator all the time but didn't realize there was that option/feature to it. Quickly punching in approximate numbers (my session sheet/numbers are at home), I get a conversion efficiency of ~72%. Lauter/sparge efficiencies are fine from what I can tell and brewhouse is slightly lower than mash.

In terms of troubleshooting conversion efficiency:

• I build my water profile off deionized water using Bru'N water targeting a mash pH around 5.3. I measured it on this batch at 5.25 which is a bit lower than expected but, reasonable.
• My crush is currently set to about the width of a credit card. I am not sure if that is too low or too high, given my desire to recirculate and would love some guidance from someone who has success doing BIAB recirculation as to if I should increase the gap or decrease the gap in an effort to maximize recirculation.
• I think that leaves me with needing to improve dough in and/or recirculation. What are people's suggestions on how to improve recirculation? Would any of the ideas discussed above (increasing mill gap, changing recirculation return to be on top of the grain bed, etc..) be advised or are there other things that I should try?

Thanks for the help! Hopefully I can get this sorted out...

 

[pricelessbrewing]

NP. Let me know if you have any feedback on my calculator.

Do you dough in by hand first? I would definitely do that, then switch to the recirc once it's all broken up.

As far as recirculation specific trouble shooting, I have no idea. I do use one.

 

[andrewmaixner]

Your system sounds very similar to mine (see https://goo.gl/photos/gkuuU55rpdBnr6qp7 ) I set my crush so the rollers were quite tight on a .041 metal feeler gauge setting.

Perhaps you could post pictures of your system?

You said that your recirculation goes in15 inches below the top of the kettle. That could be skipping a lot of the grain, though a few stirs should negate that as you mentioned.
I adjust my recirculation input so that it is just a couple inches below the top of the mash.

How well did you let it drain before rinsing? Could your rinse have been channeling instead of rinsing it all?

 

[zman_]

NP. Let me know if you have any feedback on my calculator.

The most pressing feedback I can think of is: the calculator is pretty darn awesome. The inches per gallon conversion and everything provided in inches makes it much easier to measure everything (as I am cheap and don't have volume markings). One minor thing I can think of that I have been missing is having "saved sessions" or "equipment profiles" so I don't have to enter all my parameters each time I use it. That is likely beyond the scope of what you're trying to do and having to type in a few numbers each time I use it isn't terrible by any means, but would be nice. The other thing I can think of would be to have a print layout that fits easily on a single sheet of paper for people who don't want to have a computer around when they are brewing (although I always do).

Do you dough in by hand first? I would definitely do that, then switch to the recirc once it's all broken up.

I do dough in by hand first and try my best to ensure even incorporation of the grain/no dough balls/etc. I currently have a stainless mash paddle but I've been considering getting one of the oversized wisks for better dough ball killing potential. I generally dough in, wait for 10-15min for temps to equlibrate/etc, take a pH sample (and get it cooling), before priming the pump and trying to get recirculation started. It worked well for my full-volume batches (start slow, set the bed, then speed up), but never really got started on my most recent batch.

Your system sounds very similar to mine (see https://goo.gl/photos/gkuuU55rpdBnr6qp7 ) I set my crush so the rollers were quite tight on a .041 metal feeler gauge setting.

Perhaps you could post pictures of your system?

It does look pretty similar to your system. One major difference is that I have a solid sided basket which should help to channel all liquid through the grain bed instead of creating currents through the lower-resistance mesh sides, but I think that also makes my recirculation efforts more difficult (reliant on good filtration through the grain bed).

I will try and snap some pictures when I get home. I have to put everything back on the stand to take the pictures but that shouldn't be too terrible.

You said that your recirculation goes in15 inches below the top of the kettle. That could be skipping a lot of the grain, though a few stirs should negate that as you mentioned.
I adjust my recirculation input so that it is just a couple inches below the top of the mash.

Yeah, its a 15" whirlpool arm designed (given the name) for whirlpooling primarily. I was hoping that, if the mash was thin-enough that I would be able to create enough motion to get the recirculation benefit. Also, I wanted to keep my options open for doing 5g batches in the 20g pot so I needed it to reach pretty low. I think I will make some adjustments so that it returns just a few inches below the top of the mash, I just need to work out exactly how to do that (free-hanging silicone tube, or rotating the TC whirlpool arm, or getting a shorter whirlpool arm made, or connecting my contraption to the stand mast, etc...). Hopefully pictures will clarify what I am talking out a bit.

How well did you let it drain before rinsing? Could your rinse have been channeling instead of rinsing it all?

I suspended the bag over the kettle for ~10+ min and also did a bit of a "squeeze/press" with a bucket lid to make sure that I got a good amount out. I hit the expected first-runnings volume so that went as expected. Also, even my first running gravity was low, indicating that the issue was present even before sparging. I don't think the rinse was channeling as the sparge efficiency is good in the above efficiency calculator and the sparge appeared to saturate the grain bed/drain pretty slowly, but it is always a possibility.

 

[pricelessbrewing]

The most pressing feedback I can think of is: the calculator is pretty darn awesome. The inches per gallon conversion and everything provided in inches makes it much easier to measure everything (as I am cheap and don't have volume markings). One minor thing I can think of that I have been missing is having "saved sessions" or "equipment profiles" so I don't have to enter all my parameters each time I use it. That is likely beyond the scope of what you're trying to do and having to type in a few numbers each time I use it isn't terrible by any means, but would be nice. The other thing I can think of would be to have a print layout that fits easily on a single sheet of paper for people who don't want to have a computer around when they are brewing (although I always do).

If you go to the top right, there's a "data functions" section. Click that, then you can either save the data locally (saves all input variables, and ties it to the "saved Data" input. So you can enter "Template" into Saved Data, then click save data locally. Close the browser, re open it, and click Load local data and all the "template" info will be entered automatically.

Alternatively, you can click export data, and it will fill the "saved data" text box with a string of all your input variables. You can save this wherever you want, in a spreadsheet, a notepad, email doesnt mater. Close the browser, re open it, and paste the datastring into Saved Data and click "import data". All the data will get entered automatically.

Eventually I'll switch to BeerXml, but that'll need recipe formulation first.

As for print layout, I'm still thinking about how I would be able to do it. I'm an amateur-grammer not a pro-grammer so it takes me awhile to learn new stuff that I want to do. But it's on the to-do list.

I do dough in by hand first and try my best to ensure even incorporation of the grain/no dough balls/etc. I currently have a stainless mash paddle but I've been considering getting one of the oversized wisks for better dough ball killing potential. I generally dough in, wait for 10-15min for temps to equlibrate/etc, take a pH sample (and get it cooling), before priming the pump and trying to get recirculation started. It worked well for my full-volume batches (start slow, set the bed, then speed up), but never really got started on my most recent batch.

That should be fine given your mill gap and pH. I would recommend NOT using the recirculation on you rnext brew, and seeing what your conversion efficiency is. If it's still <90%, then focus on that before doing the recirc. Otherwise maybe a recirc expert will chime in with some ideas.

 

[zman_]

...Well I didn't even know those were options. Thats amazing!

To the people (person?) who wanted pictures, they are attached.

Looking at them, I am not sure why I thought that I would ever get an efficient recirculation with the whirlpool arm/recirc return so low in the mash basket. I think the major thing that I need to do is find a way to return the recirc higher into the mash. Thoughts? Silicone tube? LocLine? Shorter stainless WP arm?

Question for those who recirc - what mill gap do you use? Do you find any benefits/troubles with a smaller/larger gap? It would seem to me that a smaller gap would make recirculation harder/slower, but I am not sure if that is actually the case.

 

[andrewmaixner]

Aah, I thought you might have one of the colorado brew systems. Here is a huge thread and a smaller thread that might help you, specifically about the several iterations of your system:
https://www.homebrewtalk.com/showthread.php?t=575659
https://www.homebrewtalk.com/showthread.php?t=530987

 

[wilserbrewer]

My guess would be that a significant portion of your water outside the basket never passed through the grain decreasing your lauter. Even a manual recirculate of this water may have helped considerably.

 

[TexasWine]

My guess would be that a significant portion of your water outside the basket never passed through the grain decreasing your lauter. Even a manual recirculate of this water may have helped considerably.

This^^^^ If you were never able to really circulate, then you had a substantial amount of water just sitting outside that pretty solid sided basket. That would hurt your efficiency.

As far as not being able to circulate, your mash was definitely thicker this batch than the others, but not sure if that was the issue. I personally use a gap of 0.040. Others go all the way to 0.050. The problem with using a fine crush when circulating the wort are many fold. Compacted bed and channeling if a passage is found are two.

I personally prefer a bag lining the entire kettle as opposed to a basket. You get more cross sectional area for a given kettle, which means a lower face velocity and a lower chance of having flow issues. Also, there's no way to bypass the bag lining the kettle as with a mesh sided basket.

 

[zman_]

So, I'm not so sure that is the issue. Given the slow filtration through the grain bed/mesh bottom, I was consistently having to throttle the pump down/stop any flow since I was pulling all of the liquid from outside of the basket into the basket (increasing the volume within the basket to dangerous levels and risking pulling air into the pump). Because of this, I pulled all of the "dead water" through the grain bed a few times. I am more inclined to think that mechanism of water/wort return into the grain bed is pretty crap (as it is so far down into the bed) and makes the bed unable to set/filter appropriately. The dead space might become a problem when I have more efficient filtration, but I don't think its the issue for now.

Reading through the topics on similar systems, I have found other people with a similar problem with recirculation/etc but haven't found any great solutions...although I still have to get through the bulk of the 90+ page topic.

 

[andrewmaixner]

So, I'm not so sure that is the issue. Given the slow filtration through the grain bed/mesh bottom, I was consistently having to throttle the pump down/stop any flow since I was pulling all of the liquid from outside of the basket into the basket (increasing the volume within the basket to dangerous levels and risking pulling air into the pump). Because of this, I pulled all of the "dead water" through the grain bed a few times. I am more inclined to think that mechanism of water/wort return into the grain bed is pretty crap (as it is so far down into the bed) and makes the bed unable to set/filter appropriately. The dead space might become a problem when I have more efficient filtration, but I don't think its the issue for now.

Reading through the topics on similar systems, I have found other people with a similar problem with recirculation/etc but haven't found any great solutions...although I still have to get through the bulk of the 90+ page topic.

Sounds like some of the more recent posts there have had good luck replacing the low return arm with just a high silicone hose, or with a SS BrewTech recirculation manifold https://www.ssbrewtech.com/products/re-circulation-manifold-for-infussion-mash-tuns

 

[ReverseMonk]

Sounds like some of the more recent posts there have had good luck replacing the low return arm with just a high silicone hose, or with a SS BrewTech recirculation manifold https://www.ssbrewtech.com/products/re-circulation-manifold-for-infussion-mash-tuns

I've often looked at those ss brewtech manifolds, with the idea of putting it at the bottom of the mash sitting on the false bottom(not at the top), and using a fairly forceful pump flow to keep the whole mash flowing up in suspension. Temps would be super consistent, I would think that extract efficiency would improve (and possibly be faster and more consistent), and you would eliminate compacted grain beds and the problems that stem from that. I know you might wind up with a fairly murky wort, but I'm not worried much about that.

Anyone have any practical experience with this manifold in BIAB brewing?

 

[newnick]

I've been recirculating for a pretty good while now. This is what I would try if I were you. Make a 5 gal. batch, full volume recirculating to the top of the bed with a normal crush not a fine crush. See if your luck is better. I believe your crush might be to fine and your making to high of a gravity batch for the size of your kettle. Maybe try a 7.5 gal. batch.

 

[zman_]

Thanks for the suggestions. At least from some quick calculations, I should be able to mash that much grain, and quite a bit more, without getting too thick (taking the normal ~1.25qt/# thickness as an upper limit). But I do agree that I need to work through the recirculation. I think I will first try doing a bit thinner mash, but still adding in in a sparge step (so maybe ~30# of grain or so) with a silicone hose returning the wort on top of the grain bed (starting slow/etc before ramping up). If that goes well, great. If not, then I can look into breaking down into smaller batches, manifolds, etc.

 

[doug293cz]

You have a significant volume of water/wort outside of you basket. That liquid really doesn't contribute to your effective mash thickness. You should be using:

Effective Mash Thinning Volume = Strike Water Volume - Outside Basket Volume​

to calculate your effective mash thickness. You are trying to recirculate thru a much thicker (less fluid) grain bed than you think you are. If you keep your effective mash thickness (as defined above) thinner than 1.25 qt/lb, your max grain bill weight will go way down.

Also, as beat to death above, get the recirc return up near the top of the mash.

Brew on