# Recirculating Mash



## Hogan (21/8/07)

I've seen a number of 'arms' that are used in the recirculation of mash to clear it prior to mashing out or sparging. They seem to be mostly manifolds that redistribute the runnings across the top of the mash until they are seen to be clear, the recirculation stopped and the run-off commenced.

Are these arms really necessary for recirculating? 

Could not the top inlet for the recirculation be mounted below the high mash level and the runnings pumped back into the mash without the need for 'arms'. The pressure of the March Pump should stop any flow-back and the fact that the recirculation is going in below mash level should alleviate HSA. Obviously the top inlet would require a ball value which would be turned off with the cessation of pumping. 

A top inlet mounted at a level below the lowest predicted mash level would also remove the necessity for 'adjustable heights' for recirculation arms. 

This is not meant to apply to fly sparging.

Have I got this recirculation business all wrong or what??


Cheers, Hoges.


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## Jye (21/8/07)

A return manifold isnt really that important and what your proposing could very well work. I think it is Justin who just lays a length of silicone tube on top of the mash and recirculates through that, you cant get more simple than that.


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## Hogan (21/8/07)

Jye said:


> A return manifold isnt really that important and what your proposing could very well work. I think it is Justin who just lays a length of silicone tube on top of the mash and recirculates through that, you cant get more simple than that.




Jye - why does it have to lay on top of the mash? Ok, if it was coming in over the lip of the tun that's understandable. But... if the recirculation is being injected through the tun wall what is to stop that injection going directly into the mash below its high level rather than being splashed on the surface. 

Cheers, Hoges.


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## matti (21/8/07)

Look hereLinky.
The actual recirculation copper manifold is meant to be kept under the surface.
I think you are right on thr money here.
I am no expert in equipment but I think it may be worth to a put a ball valve at entry point to mash if you don't have the manifold. 
matti


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## therook (21/8/07)

matti said:


> Look hereLinky.
> The actual recirculation copper manifold is meant to be kept under the surface.
> I think you are right on thr money here.
> I am no expert in equipment but I think it may be worth to a put a ball valve at entry point to mash if you don't have the manifold.
> matti



That links not working for me matti?

rook


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## Jye (21/8/07)

It would be undesirable to inject the recirculated mash downwards, this would disturb the mash bed (grain filter) and the recirc would not clear. If this was happening then a manifold of some type would be need to redirect the recirc upwards.


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## matti (21/8/07)

sorry not for me either but ckeck the grain and grape web site herms systems . http://www.grainandgrape.com.au/articles_o.../gg_herms01.htm
There a picture of the copper manifold and the text explains


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## Hogan (21/8/07)

Jye said:


> It would be undesirable to inject the recirculated mash downwards, this would disturb the mash bed (grain filter) and the recirc would not clear. If this was happening then a manifold of some type would be need to redirect the recirc upwards.




It would not be injecting downwards - just sideways. The small amount of pressure exerted by the March pump should not affect the grain bed when you consider the mash depth, even in a converted keg.

Cheers, Hoges.


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## Screwtop (21/8/07)

Hogan said:


> It would not be injecting downwards - just sideways. The small amount of pressure exerted by the March pump should not affect the grain bed when you consider the mash depth, even in a converted keg.
> 
> Cheers, Hoges.




Correct Hoges, mine runs down under the liquid level and then sideways around the inside of the tun, a bit like whirlpooling, no problem with clear wort, as a matter of fact it improved my run off, used to get that mud/sludge over the top of the grainbed which slowed/stopped the run off. Recirculating during the rest results in beautiful clear wort, mash out is simply directed to the kettle instead of the MLT return.

Screwy


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## deckedoutdaz (21/8/07)

This link will work...

www.grainandgrape.com.au/articles_other/gg_herms01.htm

Daz


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## Tony (21/8/07)

I am guessing you are talking about a fixed return in the tun as aposed to the sparge arm most of us use that go through the top or lid to return the wort.

QUestioning the institution hey...... I LIKE IT 

I did origionally plan to do just this, even mounted a very basic verson but it got in the way when i opened it up to stir the mash or remove the spent grain after the mash

I have mine mounted in the lid so when i remove the lid , it comes out with it, giving me unrestricted access to the mash.

Also if it blocks up for some reason (had it once when an experimental false bottom buckled) its easy to lift out, backflush and return to the brew in a few minuites.

have you ever had to go elbow deep in a 66 deg mash.

I have!

Try it some time..... i dont want to 

thats why i made mine come in through the lid to make it easy to remove.

apart from that there is no real science in it.... just what works for me 

cheers


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## ant (21/8/07)

I have a sparge arm that sits ~6-12 inches above the mash, but delivers only water from the HLT during mash-in and sparging. I recirculate continually for the duration of the mash, exiting from a ball valve underneath the false bottom, and coming back to a full coupler in the top of the MLT. I went for a full coupler as it meant I could put a quick disconnect on the inside of the MLT, which allows me flexibility to change the setup, but currently it has a length of silicone hose which goes around the side of the MLT and sits about an inch or so below the level of the mash. Also easier to remove to pull out the false bottom and clean, etc


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## Justin (22/8/07)

Yeah Hogan, you are on the money in that there is no real science in it-anything will work and what you are proposing would work I'm sure. The only down side I can see is that you are kind of locked into the size of your mash (via the height of the mash). Obviously this depends on your mash tun and how much you vary your mash size, on a big batch you might end up feeding the recirc back into the middle of the grain bed a bit if your return is set up for 5 gallon batches for example. Depends on how you have set up your system and its size etc and if you do batches of varying size.

I do only use a length of silicone hose now I'm batch sparging and it self levels beautifully by itself when I'm recircing, however even if I was fly sparging the hose would work fine as well without a manifold (however I did have one like everyone else when I was fly sparging but now that I have set up a HERMS and recircing constantly I've come full circle again and I'm back to using a very simple manifold-not much more than a T piece in the end of a hose). 

Don't know about you guys but when I was fly sparging and also recircing to set the grain bed before run off the rate at which the return/sparge water was entering the top of the tun it was never going to bore a hole to China in my grain bed. 

I've found in actual use it is pretty hard to upset the grain bed, as in my mash tun the depth prevents any disturbance in the upper portion getting down to the bottom. I use the old 50L stainless MT variety . When batch sparging obviously it doesn't matter how your water gets in there, and honestly it doesn't take much to set the bed and start getting a clear run off when you recirc so you don't really need elaborate return mechanisms unless you have a "really" shallow grain bed.

What do you propose to be the real advantages of setting your recirc up in this way through the side over just setting up a conventionl mechanism? I have no problems with your idea, like Tony I'm keen to see new thoughts and idea etc, but I'm not sure if you will gain too much advantage over the traditional method of doing it. I agree it might be simpler than height adjustable return manifolds but as a few have suggested above about the height adjustable manifolds, nice but not totally necessary.

Some of the downsides I could see in your design are 1. not being able to see the flow rate of your return by checking the output, you'll be flying blind on exactly what your flow rate will be out of the pump. 2. If your flow stops and you get a stuck run off, unless your height is perfect and you an see the current of water/wort flowing back into the tun you might not be able to see it easily straight away (I'm always pulling my hose out of the surface to check the speed it's flowing at). Worth thinking about as that might sway you one way or the other?

If you are worried about rigging up a mechanism to come through your lid, why not do it how I have which is basically exactly what you have proposed but I've come back in the side of the tun nearer the top. That suits any size mash and you can just use the hose to get down to your bed height. Just don't use a hose that is too short so it shoots directly into your bed, a bit of extra length is good here so it lays on the top and directs the flow from driving straight in. You can see what I'm talking about here: http://hbd.org/discus/messages/366/33903.html?1187582191

Happy to keep the discussion up. Nice to see a good brewing related topic to chat about.

Cheers, Justin


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## Stuster (22/8/07)

Just to play devil's advocate, I'd just like to point out that there may not be such a huge need for recirculating. Research in the last ten years seems to show that getting a crystal clear run-off is not the benefit it was thought to be. I'm certainly not saying it will hurt your beer to do it, but it may be of little or no benefit. Now if you feel better doing it, then go right ahead, but just don't say I didn't try to save you some work.  

If anybody's interested in reading a load of science :blink: the study is here. Basically, the study showed that there was almost no difference between beers made with clear or turbid wort from the lauter tun. Taste tests were the same, clear wort beers kept slightly better, but fermentation and head retention were better from the cloudy wort. 

Anyway, as I say, not to put you off if you want to do this, more to reassure people that there's no need to go crazy getting crystal clear wort. As long as you keep the big bits out of the boil, you'll be fine.


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## Sammus (22/8/07)

My first HERMS attempt didn't even get me crystal clear runoff... it was clear sure, clearer than the first litre of runoff from my non herms batches.... And i was recirculating super slow with a manifold of sorts that didnt disturb my grainbed (which was also quite deep, given my 50L s/s type of mash tun)... only thing I got from it was temp stability and a 10% drop in efficiency (i'm pretty sure that was due to something else though)


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## Lukes (22/8/07)

I use the silicone hose and copper elbow's method too.
You can see it sinks a little into the mash in a 50 ltr tun.
Batch sparge.







- Luke


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## devo (22/8/07)

i don't bother with a manifold anymore. I simply use a single piece of hose and get a pretty clear run off after a 15 minute reticulation.


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## razz (22/8/07)

When it comes to recirc during the mash I'm with Stuster on this one. I haven't done it for sometime now and it hasn't had a negative effect on my brews. In fact, I find I'm getting more consistent results with efficiency. I only bother to recirc through the herms for mashout.


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## SJW (22/8/07)

After seeing what they use up at Potters Brewery I stopped worrying about my system. At Potters in the Mash Vessel they use what could only be decribed as a glof ball shaped shower head that sprays water from a great height.(Maybr Scotty could expand a bit more on this) So with my 2 inch fall from a copper pipe with a splayed end on it, and valve controled from the pump I dont think it is such a big deal how u do it!  

Steve


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## Zizzle (22/8/07)

Hogan I've done exactly what you have suggested before with my brewbot.

Check out my Keep Cold mash tun:






I didn't want to put a hole in the lid since I plan to move away from this tun eventually and sell it on.

So I pulled out the thermometer out and put the hose into there, which you can see is pretty low on the tun.

I don't have HERMs setup yet, so have programed the 'bot to just do a 1 minute recirc at the end up the mash/sparge to clear up the wort.

I have a flow switch in the wort loop so I can still tell if a sparge is stuck.

I'm hoping that having clearer wort at sparge time means less trub in the kettle at the end (and so less loss) but haven't really tested the difference.

But so far, despite reentry being quite low in the grain bed, it seems to clear up the wort nicely.


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## Hogan (23/8/07)

Apologies for not answering sooner but have been away from the keyboard for couple of days.



Justin said:


> I've found in actual use it is pretty hard to upset the grain bed, as in my mash tun the depth prevents any disturbance in the upper portion getting down to the bottom. I use the old 50L stainless MT variety wink.gif. When batch sparging obviously it doesn't matter how your water gets in there, and honestly it doesn't take much to set the bed and start getting a clear run off when you recirc so you don't really need elaborate return mechanisms unless you have a "really" shallow grain bed.



This is the point that really kicked off the original post. The power of a March pump is not much more (if at all) than what comes from a gravity feed. The only difference between them is that the pump can push the water up.




> What do you propose to be the real advantages of setting your recirc up in this way through the side over just setting up a conventionl mechanism? I have no problems with your idea, like Tony I'm keen to see new thoughts and idea etc, but I'm not sure if you will gain too much advantage over the traditional method of doing it. I agree it might be simpler than height adjustable return manifolds but as a few have suggested abonve about the height adjustable manifolds, nice but not totally necessary.



Mainly I wanted to cut through the mindset that you can't recirculate back into the mash without using a manifold. The injecting of return fluid back into the mash through a single stream will not upset the grainbed or cause HSA when it is done below the surface. As SJW says, at Potters they bomb the return liquid from high up back into the tun. Even so your idea of having the inlet up high and running a silicon hose from the inside down to mash is a good one.



> Some of the downsides I could see in your design are 1. not being able to see the flow rate of your return by checking the output, you'll be flying blind on exactly what your flow rate will be out of the pump. 2. If your flow stops and you get a stuck run off, unless your height is perfect and you an see the current of water/wort flowing back into the tun you might not be able to see it easily straight away (I'm always pulling my hose out of the surface to check the speed it's flowing at). Worth thinking about as that might sway you one way or the other?



Both good points and definately got consideration during the head scratching process.





Stuster said:


> Just to play devil's advocate, I'd just like to point out that there may not be such a huge need for recirculating. Research in the last ten years seems to show that getting a crystal clear run-off is not the benefit it was thought to be. I'm certainly not saying it will hurt your beer to do it, but it may be of little or no benefit. Now if you feel better doing it, then go right ahead, but just don't say I didn't try to save you some work.
> 
> Anyway, as I say, not to put you off if you want to do this, more to reassure people that there's no need to go crazy getting crystal clear wort. As long as you keep the big bits out of the boil, you'll be fine.



You're not the devils advocatae Stuster but a breath of fresh air. Whilst researching this topic I have also found support for the belief that *not* removing the little bits and pieces of chaf that get through the grain bed into the kettle is not such a bad thing. Time is not really a constraint with my brewing day but I also do not want to waste it unnecessarily performing tasks I do not need. I will be doing a temperature step mash on friday using my old esky and immersion heater. This time I will not be carrying out the plastic jug ladle process from runoff line back into the top of the mash until clear. I will let it all go into the boiler and rely on my filtering process from the kettle to the fermenter and the fermenter into the keg to trap any bits and pieces. I'll report on the result and if satisfactory there will be one less hole to drill in my new MLT and no recirculation system required.




razz said:


> When it comes to recirc during the mash I'm with Stuster on this one. I haven't done it for sometime now and it hasn't had a negative effect on my brews. In fact, I find I'm getting more consistent results with efficiency. I only bother to recirc through the herms for mashout.



Razz I think Stusters comment was aimed at wort clarity during the mashout and sparge phase - not recirculation during temperature steps.


Thanks to all for their input, ideas and suggestions. No negatives received here, just a different slant on the positive. 


Cheers, Hoges.


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## Pumpy (23/8/07)

One of the things I enjoyed most about recirculating the mash was watching the the wort get clearer thinking ,this was going to make for a better beer .  

Following your post I will not enjoy my mashing the same from now on ,thinking it may be a waste of time 
 

Hoges you "Kill Joy "

Pumpy


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## Tony (8/9/07)

I dont think clearing the wort is a bad thing. 

I had a good read of all that and i think ita all probably true. I would rather the smother beer than the reduced head retention. I dont have a problem with head retention anbd my beer is smooth and clear so i will stick with recirculating

Here is what it takes out of your beer.

this is a pic of what settles on top of the mash when you recirc to clear it.

just to think this could end up in the kettle kind of makes me think its worth while

cheers


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## Weizguy (8/9/07)

Tony,
That's a nice pic of tieg.

However, I read that it's not filtered out by the mash bed, but is a result of the proteins in the bed becoming cross-linked and set a bit like a rubbery jelly.

I often get that in my beers. Probably more the result of a good protein rest, than good recirc.

Happy to be disproved.
Seth


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## bugwan (9/9/07)

I recirculate into a saucepan (normally three runs of 500MLs) and then pour that back over the grain bed. It's one part of the brewing process that seems never to be questioned and yet one we all religiously include in our brew days...

I always thought that it was meant to firstly clear the wort of husks (prevent tannin extraction/astringency via the boil) and to settle the grain bed. Frankly, I've never seen a grain husk in my recirc liquor, nor does the grain bed seem to need any more settling than it's already received over the previous hour of stasis.
I use a stainless braid in the MLT, so there's no chance of Tony's bucket of sludge reaching my kettle! I hope...


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## Thirsty Boy (9/9/07)

Thanks for the link to that study Stuster, very relevant for some stuff that I am trying to work out with BIAB brews. But... back on topic.

I'm with SJW, I have seen too many commercial set-ups that splash, bash and stir the shit out of their mash, sparge or wort, that I choose not to worry about the whole HSA thing. I try not to actually splash the stuff around too much... but I don't try all that hard

I have my HERMS return manifold (which is just a bit of tubing with some holes drilled in it) mounted on the inside of the lid of my eski mash tun; the liquid simply falls the distance to the surface of the wort. If it were an open system, I'd worry about heat loss during the fall, but inside a closed insulated container... where's it gonna go?

I've actually only just started to constantly recirculate, giving it a trial to see what it does to my temp stability. I only ever used to run the HERMS to move up a temperature step and for a final vorlauff. But I have never (well, once or twice just for fun) tried to shoot for brightly clear wort, I just run the pump for a few minutes for each batch sparge round until it isn't opaque any more. If it were taking me 20 or 30 minutes instead of 2 or 3, I would only bother to recirc till there were no chunks and be done with it.

Interestingly, and fairly on topic for this thread; as a part of one of the boringly repetitive BIAB arguments I find myself unable to resist participating in... Darren has proposed that you might even be able to boil the whole grist without doing terrible damage to the final quality of the beer... thus resulting in you being able to dispense with the bag part of BIAB and the majority of other kinds of systems.

Now I think that there is a fair chance that Darren is actually taking the piss out of me... but I have decided to give it a go just for the sake of science. I think there is a very slight chance it actually might work... Decoctions boil the hell out of a portion of the grist; in a triple decoction, probably most of it gets boiled eventually. Why not just boil the whole lot at the end of the mash and be done with it?? Then when you lauter, you are lautering out your spent grain, your hops, your break material and anything else... and putting finished wort straight through a counterflow and to the fermentor.

I dont really expect it to do anything apart from produce a whole lot of tannins and a nasty starch haze (at a minimum) but I reckon its worth a crack with small batch experiment at least.

Anyway, I think Hogans idea of a return below the surface of the wort would work just fine.. you could almost set up a "mash whirpool" that would achieve the same thing as a stirrer in a constantly agitated mash system. You could at the L:G ratios of BIAB, but a standard mash would probably be a bit thick I suppose.

Sorry to ramble... I just kept thinking up more stuff to write. Better get myself a beer to take my mind off it.

Cheers

Thirsty


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## Tony (9/9/07)

bugwan said:


> so there's no chance of Tony's bucket of sludge reaching my kettle! I hope...



I hope you dont think that came out of my kettle :blink: 

was cleaning out my mash tun with the little blue bucket and saw the level of sludge that had been caught on top from the recirculation of just 5 min during the batch sparge.

cool hey

cheers


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## Ross (9/9/07)

I have more cloudy worts than clear worts going into the kettle, as the false bottom on my mash tun fits terribly & I've never got round to fixing it. I just use a hop sock to catch the bigger particles & don't stress either way. Beer quality is spot on to my tastes either way, fresh or aged. My observations are that a cloudy wort seems to have a much better cold break formation at the end. This is maybe why I've had some problems with long term stability when trialling "no chill", as there's much more break transferring to the fermenter. 

cheers Ross


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## domonsura (9/9/07)

For the return into the lauter tun, I just use a plain old piece of tube, I've messed around with all manner of return bowls/plates/disperser mechanisms and they all added one thing - something else to clean, without providing any other benefits over the straight hose return (which sits just under the surface of the mash water level. Pictured here while I'm slicing the top of the mash....)





I use my pump to recirculate the entire sparge water mass through my mash and the kettle continuously for an hour as my sparge, I recirculate directly into the mash/lauter tun until it clears initially, and then swap the hose over to the kettle and blast the runnings straight in there....(I have 2 ball valves on my kettle) Here's a snap of the first runnings entering the clean sparge water in the kettle.....always a bit of a moment for me...





So I don't sparge into a separate vessel at all, and when I'm finished the sparge, I simply turn the burner on to start raising the overall temp (sort of mashout) till 75-80 degrees, and then I tuen the return to the tun off, and allow the kettle to finish filling with the burner on. Usually, by the time the tun is empty, the kettle is starting to boil, I let it do it's little hot break thing then make the first hop addition.
I tend to achiever 75% eff plus routinely, usually a little higher especially since I have standardised my crush by getting my own mill, and have been using BB malts lately as well which I seem to get better eff with....

For what it's worth Ross, by nature of the way I run everything through the chiller straight from the boil in the kettle, all of the 'cold break' goes into my fermenter. I haven't really noticed any stability issues. How long would stability issues take to raise their ugly heads?
Also for what it's worth, I don't bother getting the wort crystal clear (as you can see) before I bump it over to the kettle, because regardless of if it's clear or a bit cloudy, the wort out of the kettle is crystal clear inevitably as long as there is a good boil. I just make sure that there aren't solids getting in there....


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## Ross (9/9/07)

domonsura said:


> For what it's worth Ross, by nature of the way I run everything through the chiller straight from the boil in the kettle, all of the 'cold break' goes into my fermenter. I haven't really noticed any stability issues. How long would stability issues take to raise their ugly heads?



3 to 6 months... Which is unlikely to affect many people who are kegging. I have no idea whether the same problem would occur with bottled beer that tends to be kept longer.

Cheers Ross


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## chris.taylor.98 (9/9/07)

One question I have is to what extent flavour variation is effected by wort clarity.

I have found that I was getting some astringency and a distinctive grainy flavour when not recirculating enough. 

Cheers 
Chris


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