# Adding Recirculation - My Easy Urn Upgrade



## RobB

For years my brewery has been very simple; just a 40L Birko urn, a voile bag and an over-the-side element for step mashes. After a few years of watching jealously from the sidelines as the Braumeister took off, I went to a friend’s BM brewday and was bitten by the recirculation bug.
I had the funds and spousal approval to buy a Braumeister but I couldn’t bring myself to buy one without at least _trying_ to build my own recirculating system. What I ended up building borrows heavily from QldKev’s system as well as the Grainfather, except that I intend to use this as a full volume (i.e. no sparge) system.
Apart from working well, I wanted my new system to be as simple as possible to minimise the parts which would need cleaning and to keep the cost down if it all turned to crap and I ended up buying the Braumeister anyway. It also had to be built with my fairly limited skills and tools. For these reasons, I decided to recirculate downwards, mimicking the Grainfather and BrewEasy rather than the Braumeister.
I brew 12 litre (3 gallon) batches, but I think this system would work well for normal 19 litre batches even though it may require a sparge step to be added. Alternatively, you could apply the same ideas to different vessels.
The malt pot is the good old Big W 19 litre stock pot. Its thin walls make it cheap and easy to work with. Four stainless bolts make up the legs, the handles have been cut off and replaced with holes for hooks, and the bottom has been butchered to drain the wort. The slots were made with a 1mm cutting disk every 10 degrees and are 3cm long with 1cm spaces.......at least that’s what they were meant to be (don’t look too closely, I told you my skills were limited!). It’s pretty much a carbon copy of QldKev’s until you get to the big hole in the middle.



The hole is for the overflow drain, which is similar to the Grainfather’s except that their telescoping version was beyond my capabilities, so I will use different lengths of threaded pipe according to the size of my grain bill. No thread tape is necessary; some wort will flow through the mash and some will flow down the central pipe. If there is a leak path between the two, it’s not an issue.


This bit is important – Unlike the Braumeister and BrewEasy, which have very low density elements, urns like the Birko have high density elements. If wort proteins and flour are allowed to build up around a high density element, they can be scorched which will ruin your brew and quite possibly your element as well. Regardless of what your system looks like in the end, I strongly recommend that the wort flow is kept high when using a high density element. QldKev’s system lets the pump run flat out and he uses ball valves to balance the flow between the malt pot and a bypass. I do something similar, except that my bypass is the central drain. The pump still runs flat out, but I let gravity sort things out rather than plumb in two ball valves.
I need a top filter to stop grain disappearing down the central drain, and this was made using an Ikea spatter guard (of course!) and an HDPE chopping board which I cut up. Esky mush tuns are made from HDPE, so I am comfortable using this material in my mash, particularly since the product from which it was cut was intended for food preparation and is dishwasher safe. The frame is nice and rigid and the material was so easy to work with.


Here’s the assembled system – note the lack of valves. When it is not in the kettle, I simply keep the outlet hose elevated by draping it through one of the urn’s handles. The hose connectors are stainless and silicone nut and tail connectors from Nev at Online Brewing Supplies. I love these connectors! The thread doesn’t play a role in the seal, other than to squeeze an O-ring against the end of a male fitting, so again there is no need for tape. The pump is a Kaixin which puts out 19 L/min at zero head and about 15L/min once it is draped up onto the top filter.


The pot drains by sitting on a repurposed shelf from a bar fridge.
It’s all very simple, but does it work? Here is its maiden brew:
Dough in at about 40 degrees. My crush was fairly coarse and I added 5% rice hulls. The water volume was calculated such that when the wort reached the overflow pipe inside the pot, the wort level in the urn would be just above the bottom of the pot. This would give a good head difference to ensure flow through the grain, while ensuring that the wort wasn’t “raining” back into the urn. Opinions vary on HSA, but 90 minutes of constant rain is tempting fate.


I stirred the mash and let it sit for five minutes before turning on the pump. To my relief the level in the malt pot only crept up very slowly, indicating that most of the liquid was heading downwards through the mash. The level eventually rose to the drain, but the trickle going down there was far less than the 15 litres per minute gushing from the outlet.....for now........
By the end of a 52 degree protein rest, it was clear that more wort was going down the central drain. I decided to check for a stuck mash, which is easy to do with this set up. I simply directed the outlet hose down the gap between the urn and the pot and watched the wort level in the pot. When I saw that the wort level kept dropping below the top of the drain, I knew that wort was still flowing through the grain, just not as much as the pump could dump on top. That’s OK; that’s what this design is about. The mash takes what it can while the drain lets the pump run unrestricted. Based on the rate at which the wort level dropped during my test, the grain bed was draining top to bottom in about two minutes. I was happy with that so replaced the hose ready to ramp up to a beta rest. That’s when things got weird.


The strong flow from the pump created such a strong whirlpool that the wort was actually draining very slowly down the central drain while the outer edges of the whirlpool rose steadily to the top of the pot. I was worried that I had made my drain too small (half inch) to cope with the overflow, but then I noticed that slight adjustments to the position of the outlet hose made a huge difference to the wort level above the drain. I settled on a high tech solution: I dropped a small drinking glass onto the top plate to act as a baffle against the whirlpool. The result was amazing and immediate. The wort level dropped right down with only a very sedate trickle going down the drain.
Having to tame the whirlpool was the only drama during this maiden run. I stepped the mash to beta (62), alpha (72) and mash out (78) and was left with beautifully clear wort.


I’m looking forward to adding a brain to this system. I managed the mash steps manually by turning the element on until I hit the desired temperature, then backing off the dial until the element clicked off. This kept me within 1 degree of my target for steps as long as 30 minutes. I wasn’t sure whether the urn’s thermostat would be up to the job, but with the whole wort volume recirculating every two minutes, I’m guessing that the temperature throughout the mash was very even and this kept the element from constantly flicking on and off – another benefit of rapid flow.
When I lifted the malt pot (note to self, find a lower brewing surface!) the wort drained within minutes. I was a couple of litres short, so I tipped some cold water over the top filter to give the grain a rinse. Pre-boil efficiency was 82%.
The wort I collected at the end of the boil was the clearest I have ever produced and I was able to leave the break behind easily.
The whole build was easy, fun and fairly inexpensive. For about $200 I turned my urn into something pretty special. A lot of brewers seem to be building their own recirculating systems, so I hope I have provided some food for thought.


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## Cervantes

This is brilliant...............

I'm halfway through building something very similar using an old keg with a pot inside, but this has given me the inspiration I needed to finish it off. The overflow and top filter plate are where I was stuck, but now I'm going to copy your ideas 

Then add Lael's controller once it's available and it should be done.

Just one question................

Have you considered a clamp type arrangement to hold the top filter in place rather than a nut?

I ask this as even with the BM I find that efficiency improves if the top filter is removed and the grist stirred a couple of times during the mash and a clamp would make this an easy operation.


Edit: Spelling & Clarification


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## RobB

*Item/**Vendor*/*Price* 
Malt Pot - Big W $19
S/S Bolts for Legs - Bunnings $15
Cutting Disc - Bunnings $2
Flap Disc - Bunnings $7
Step Bit - Bunnings $10
2mm Cobalt Bit - Bunnings $5
Lifting Hooks (S-hooks) - Bunnings $2
HDPE Chopping Board - (?) kitchen shop $19
Ikea Screen - Ikea $3
S/S Screws for Top Filter - Bunnings $7
Assorted S/S Pipe Bits for Central Drain - ebay $15
Magnetic Drive Pump - Back 2 Basics Brewing $75
3 x Hose Connectors (HERM-IT Soft Core) - Online Brewing Supplies $36
3 x Hose Clamps - Bunnings $6 
*$ Total* *221*


*Stuff I Already Had* 
Skin Fitting for Urn Outlet - Whitworths (yachting supplies) $17
Silicone Hose - Online Brewing Supplies $15


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## RobB

Cervantes said:


> Just one question................
> 
> Have you considered a clamp type arrangement to hold the top filter in place rather than a nut?
> 
> I ask this as even with the BM I find that efficiency improves if the top filter is removed and the grist stirred a couple of times during the mash and a clamp would make this an easy operation.


In the end I didn't even use a nut, I just held the filter down with the female coupling which also gives me my constant liquid height above the mash. I considered making the filter more easily removable by swapping two of the screws (which hold down the Ikea screen) with stainless eye-bolts to give me easy lifting points. I would still have to unwind the coupling, but that's all of five seconds. But if you have a clamped alternative, then why not? I have shamelessly borrowed from three or four existing systems, so there is plenty of room for personal touches.


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## Hairy Maclary

Brilliant work. I love how this also seems to be a solution to having burnt on malt on the Birko element.


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## paulyman

Awesome work.

I'm in the process of setting up something similar, but no where near as far along. I love the idea for the overflow pipe!

I had thought about a fixed length that I'd rise or lower into the main vessel depending on the grain bill.


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## Tahoose

I think this is a great system, and don't worry about pinching ideas if they didn't want to share it they wouldn't have posted them up.

Thanks for sharing.


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## Budron

This is a brilliant setup! I have been looking at ideas to pimp out my current BIAB system and this looks like the direction I could head in.

Do you mind if you post links to the items you bought off ebay for the S/S central drain? Or even just the descriptions?

Cheers and well done!


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## neo__04

Pretty impressed with the work on the chopping board.

How did you go about chopping it up?

So the mash filter is just the chopping board cut up as shown and a splatter guard with a few screws holding it to the chopping board?

I like it.


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## RobB

Budron said:


> This is a brilliant setup! I have been looking at ideas to pimp out my current BIAB system and this looks like the direction I could head in.
> 
> Do you mind if you post links to the items you bought off ebay for the S/S central drain? Or even just the descriptions?
> 
> Cheers and well done!


I bought the drain fittings from these guys:

http://www.ebay.com.au/itm/1-2-Male-x-1-2-Male-Threaded-Pipe-Fitting-150MM-Stainless-Steel-SS304-BSP-NEW-/111410935425?ssPageName=ADME:L:OU:AU:3160
They are cheap but the delivery (free) was slow and you get what you pay for. The material quality is fine, but the threads aren’t flash. This isn’t a problem for the central drain, since minor leaks end up at the same destination as the main flow. However, I wouldn’t use these fittings outside the urn or anywhere where a leak would cause grief – get the proper stuff from the site sponsors for this.

If you are happy to use brass, then Bunnings have plenty of options, as would a plumbing supplies shop. Bunnings had up to 300mm all-thread in brass, but I couldn’t find anything longer than 150mm in stainless. If anyone has longer stainless, it would be Wayne at Beerbelly.

For other drain ideas, here’s a similar project from a fellow AHB’er: http://aussiehomebre...r/#entry1249573




Neo__04 said:


> Pretty impressed with the work on the chopping board.
> 
> How did you go about chopping it up?
> 
> So the mash filter is just the chopping board cut up as shown and a splatter guard with a few screws holding it to the chopping board?
> 
> I like it.


The chopping board was really easy to work with. I used a drill to drill out the “corners” of each cut-out so that I wouldn’t have sharp points where cracks might start. I then cut out the shapes with a jigsaw. I used a fine toothed blade, set the speed fairly high, but took my time working around each cut. I think the board was 13mm thick.
The stainless Ikea screen cuts easily with scissors and is just screwed down with small stainless screws. The screen comes with a handle which is attached to two disks which sandwich the mesh. Once you chop out the handle and drill through the centre, the remains of the two disks actually form a nice reinforcing washer at the centre of the mesh. Just make sure you clamp the disks when you’re drilling because you don’t want the disks to tear out of the mesh if the drill bit decides to bite.

A couple more notes for anyone looking to do something similar:

In my first post I forgot to mention that I also use the pump for recirculation during chilling, so there’s another box ticked.

When sizing your malt pot, remember that the top of the drain has to sit a couple of centimetres below the rim of the pot. Allow for a constant head above the screen (I hold the screen down with a female coupling which is about 3cm long) and you lose at least 5cm of your malt pot’s height. That’s about 4 litres in a Big W 19 litre pot. The remaining 15 litres will probably only take about 4.5 kg of grain. That’s not a problem for my 12 litre batches, but for a “normal” 19 litre batch you might want to investigate alternative malt pots.

If you are looking to do something similar, keep in mind that I already owned the urn and chiller. If you are starting from scratch, take the $236 worth of parts listed above, add $300 for the urn and $100 for the chiller (based on an 18m coil of copper tubing) and you’re up to $636. That’s getting close to the Grainfather’s RRP with a smaller malt pot and the urn’s dial thermostat. To make the comparison more like-for-like, add $50 for an STC and weldless thermowell and you’re nudging $700. I’m not trying to put anyone off – I loved making it, love using it, it works beautifully and I won’t be changing anything except to add Lael’s controller – but spelling out all the facts will help fellow brewers make the right decisions. I’m quite proud of what I have built, but if you’re not a DIY’er, an extra couple of hundred will get you something similar out of a box with all the warranties and dealer support which come with it.


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## QldKev

I only just found this build today. Really like the splatter screen ontop to prevent grains escaping into the wort. I've always been worried about it as a possibility, although touch wood it has not happened to me yet. So how are the beers from it?


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## stux

Great build. Love the minimalism, without sacrificing any functionality. And minimalism means less to clean. And less to things to go wrong.


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## mosto

I've been thinking about adding recirculation to my basic BIAB setup. Currently, I use a 38L crab cooker pot in which I installed a 2200W element, ball valve and temp gauge. I use the insert that came with the pot as it makes lifting the bag out easier and I can sit on a wire fridge shelf on top of the pot to drain while I ramp up to a boil. It all works quite nicely, but I the only step mashing I do is from sac rest to mashout, and I stir the whole time during the ramp as I find the grain bed acts as a bit of an insulator to wort below it (where the element and temp gauge sit) and there is a disparity in temperature between the top and bottom of the wort. If I add a pump which draws from under the grain bed and pumps wort back up and over the side back into the insert and bag I should maintain a more even temperature, and if I add an STC (or similar) and thermowell inline somewhere in that return line, I should be able to do more step mashing. My only concern is the insert, which would effectively act as a malt pipe. It came with ~1cm holes through the bottom and the sides. One of the benefits of recirc is clearer wort by filtering it through the grain bed. However, I'm worried the return wort would run out the side holes rather than being filtered through the grain bed. Is this a justified concern? If so, any suggestions to overcome this? Could somehow 'block up' the side holes? Not sure how I'd do this.

My main reason for wanting to recirc is even wort temp and ability to step mash, but if I'm going to do it, I may as well get all the benefits.

Cheers,


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## RobB

QldKev said:


> I only just found this build today. Really like the splatter screen ontop to prevent grains escaping into the wort. I've always been worried about it as a possibility, although touch wood it has not happened to me yet. So how are the beers from it?


The beers are great. It's working really well and I'm still astounded by the clarity of the wort.



mosto said:


> I've been thinking about adding recirculation to my basic BIAB setup. Currently, I use a 38L crab cooker pot in which I installed a 2200W element, ball valve and temp gauge. I use the insert that came with the pot as it makes lifting the bag out easier and I can sit on a wire fridge shelf on top of the pot to drain while I ramp up to a boil. It all works quite nicely, but I the only step mashing I do is from sac rest to mashout, and I stir the whole time during the ramp as I find the grain bed acts as a bit of an insulator to wort below it (where the element and temp gauge sit) and there is a disparity in temperature between the top and bottom of the wort. If I add a pump which draws from under the grain bed and pumps wort back up and over the side back into the insert and bag I should maintain a more even temperature, and if I add an STC (or similar) and thermowell inline somewhere in that return line, I should be able to do more step mashing. My only concern is the insert, which would effectively act as a malt pipe. It came with ~1cm holes through the bottom and the sides. One of the benefits of recirc is clearer wort by filtering it through the grain bed. However, I'm worried the return wort would run out the side holes rather than being filtered through the grain bed. Is this a justified concern? If so, any suggestions to overcome this? Could somehow 'block up' the side holes? Not sure how I'd do this.
> 
> My main reason for wanting to recirc is even wort temp and ability to step mash, but if I'm going to do it, I may as well get all the benefits.
> 
> Cheers,


I had a similar problem when step mashing with the urn when I used BIAB. I got around this by using an over the side element for the mash steps, stirring throughout each ramp.

I think the wort would mostly run through the upper holes in the side of a crab cooker insert, which may not give you enough of a grain filter. I'm just guessing, so maybe it would be worth borrowing a pump if you can. I can't remember where I saw it, but somebody has made a recirculating system with a crab cooker in which the wort returned through a spear of copper pipe down the middle of the grain bed, rather than just returning to the top of the bed. The spear was drilled full of holes so that even if the wort went through the side holes of the insert, it would still travel through the width of the grain bed (rather than the depth).


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## Mr B

With the clearer wort, do you get less trub?

I assume so?

Are the beers brighter (less protein in the ferment or something)?


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## RobB

Mr B said:


> With the clearer wort, do you get less trub?
> 
> I assume so?
> 
> Are the beers brighter (less protein in the ferment or something)?


The wort is certainly much brighter. During a recent brew with 100% pilsner malt, I could see the element at the bottom of the urn through the full depth of the wort. That's something I would never have dreamed of while I was BIABing.

I try not to worship the efficiency gods, but I'm getting the same efficiency into the kettle as my BIAB days and slightly better overall efficiency due to having clearer wort with less trub. The improvements in clarity and efficiency are really an added bonus; I went down this path to make my rig more suitable for automation using the Brauduino.


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## dannymars

Malty Cultural said:


> When sizing your malt pot, remember that the top of the drain has to sit a couple of centimetres below the rim of the pot. Allow for a constant head above the screen (I hold the screen down with a female coupling which is about 3cm long) and you lose at least 5cm of your malt pot’s height. That’s about 4 litres in a Big W 19 litre pot. The remaining 15 litres will probably only take about 4.5 kg of grain. That’s not a problem for my 12 litre batches, but for a “normal” 19 litre batch you might want to investigate alternative malt pots.


+1

I just built a system like this with a 50L aluminium pot and one of these 19 litre BigW pots. First time using it was a stuck mash that required constant stirring. It was next to impossible to get the temperature right and hold it too, especially using gas. This overflow pipe may help somewhat (mine doesn't have one). Live and learn, I've gone back to BIAB until I'm certain I have a solution to this, may need to look at a bigger vessel.


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## darren996

Great build, I really like it.

Just curios, is the top filter required on the malt pipe ? Could you just attach a bazooka screen with a 1/2" nipple to the top of the overflow pipe, this would keep the grain out of the overflow pipe


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