Mash Tun, Hoses, And Suction?

[bignath]

Hi all,

last night i had the brewday (night) from hell.....

It ended up with me going to bed and letting the mash tun (esky w/copper manifold) slowly drain to my kettle. Upon waking this morning, went out to the brewery and found a kettle full of wort, so i ended up continuing as normal.

here's a link for that discussion: http://www.aussiehomebrewer.com/forum/inde...mp;#entry805567

Now, i have some questions for the technically minded (cause i'm clearly not one of em).

This was the third brewday in a row where all of a sudden my mashtun isn't draining properly. Previously has worked sweet as. My best time for a double batch is 4hrs 45mins so i'm not complaining too much about that. All has been right with the world until recently.

Things that have changed:

New bag of grain. Same type and brand i always buy, but it's a freshie...
New grain mill. This seems the obvious one, but the new mill was only used for the first time for last nights batch, so it can't be that.
Have used a slightly longer length hose to gravity feed my kettle.

I have pulled the mash tun apart and checked for blockages and cleaned it up nice 'n' good. Found nothing obstructing the flow.
I did however notice that a few clamps on the hose connecting the manifold to the back of the hosetail barb inside the esky were slightly loose. I tightened them back up maybe 1 complete turn with the screwdriver.

I am wondering, if there is any effect of suction or some other physics at play when using different length hoses in an enclosed vessel like a mash tun. I am also wondering if the slightest little hint of something loose can also screw around with suction/syphon type physics laws.

I'm not talking about: "****, that's pretty loose", i mean "i'll just check those clamps, oh yeah, got another turn cranked out of em'" type loose - bugger all. Or is it???

I typically open my mash tun tap to halfway, as i'm paranoid about getting a stuck sparge. When i try to open it further, the flow doesn't change - not sure if this is normal or not.

I also recirculate approx 3 or so litres before draining to kettle to try and get a good grain bed filter happening. No problems previously doing this.

If any one has any advise i would be massively greatfull, as the last 3 brewdays have been bloody painfull. Used to be able to tell the wife and kids, "daddy will be back around blah blah blah time", but now brewday has completely lost all reliability with timing due to collecting my runnings.

Hope i've included enough info about my processes that concern this problem.

Cheers in advance for your help,

Nath

 

[jyo]

Hey, Nath.
Not sure about the length of the hose making too much difference over the short distance from the tun to the kettle.
This might be a stupid Q, but was the grain bed compacted? I've had 2 almost stuck sparges (using a 55 litre esky with copper manifold) where the grain bed became really hard. I was batch sparging and came back outside thinking that it had finished...This involved me blowing air back up through the manifold to unblock, re-stirring and draining really slowly.
I think I was draining too fast though. To remedy I now sparge a lot more slowly (about 1.5 litres a minute) and a couple of handfuls of rice gulls in every brew regardless is simply magic
Hope you get it sorted, mate. It's a PITA.

 

[bignath]

Hey, Nath.
Not sure about the length of the hose making too much difference over the short distance from the tun to the kettle.
This might be a stupid Q, but was the grain bed compacted? I've had 2 almost stuck sparges (using a 55 litre esky with copper manifold) where the grain bed became really hard. I was batch sparging and came back outside thinking that it had finished...This involved me blowing air back up through the manifold to unblock, re-stirring and draining really slowly.
I think I was draining too fast though. To remedy I now sparge a lot more slowly (about 1.5 litres a minute) and a couple of handfuls of rice gulls in every brew regardless is simply magic
Hope you get it sorted, mate. It's a PITA.

Not sure how compacted it was. Didn't look much different when i dumped the spent grain in the bin later this morning. I usually get cracks through the spent grain after it's drained. I noticed that the last few mashes haven't had this so obviously.

The new mill i bought is the mashmaster mini mill (cheers Ross, it's an awesome unit) and i purchased it because i was thinking my mash might have been too fine and i wanted the ability to be able to adjust it for slight variations in grain size, and i wanted to be able to adjust it easily. My last mill (crank) was a great mill, but a pain in the ass if you wanted or needed to alter the gap setting.
The crush i got from the minimill was from a 1.1 or 1.2mm setting and it looks fantastic. Very little flour, and the grains that looked like they were untouched, literally fell apart when i picked them up. I thought this would be perfect as the husks should have made a nice filter bed and not compacted down as much. And i hit all my intended targets so i don't thing this gap setting is having a detrimental effect. Might change the setting back closer to 1mm though, as i've heard a lot of brewers like this gap setting.

I also had to blow back up the tube to try and free up some flow, but no good. Still trickled out. It's like the tap in the kitchen is on the slowest flow rate. That's what i'm getting out of my tun. It's never done this until the last three batches...it's giving me the shits.

I even tried taking the lid off the mash tun thinking it might be a similar principal to a plastic 10lt water container where you have to puncture a hole in the top to get it to flow freely due to air displacement..Didn't make a rats ass of difference. (not that i seriously thought it would).

I've got a 1/2 all thread going to a standard brass hose clip on type male connector, that takes the female clip on, and the tube goes straight to kettle.

Have also heard of brewers that are able to open their taps all the way and let it pour in. Hell, how i'd like to be able to do that....

Cheers for your thoughts,

Nath

 

[bignath]

Actually just had a thought....

If the seal on the male clip on hose attachment that accepts the female was wearing out, and therefore letting a small amount of air into the flow, would that disrupt anything???

Next brewday i might try hose clamping my transfer tube to a standard hose tail barb on my mash tun and do away with the clip on system to see if this makes a difference.

When i'm dealing with this issue "in the moment", it definitely FEELS to me that it's some kind of weird physics at play here, screwing with my system. I mean how hard can it be....Put grain in hot water, let it soak, open tap, beer comes out...


thoughts??

 

[Acasta]

I had a similar issue to this, with a REALLY slow draining. I believe the problem was having air trapped inside the tube (connecting the FB). What i've been doing since then and havn't had a problem is:
Add strike water
attach hose
open hose and lower it to fill
then lift it up fast
This should get all air out of the tubing. May or may not work, but can't hurt.

 

[bignath]

I had a similar issue to this, with a REALLY slow draining. I believe the problem was having air trapped inside the tube (connecting the FB). What i've been doing since then and havn't had a problem is:
Add strike water
attach hose
open hose and lower it to fill
then lift it up fast
This should get all air out of the tubing. May or may not work, but can't hurt.

Yeah that's kind of what it feels like is going on. Just not sure why it's only started happening though.

So, if i try your method, are you saying that when i transfer my strike water, i attach mash tun to kettle drain tube, open the tap on the mash tun, lower hose and then raise it to get the air bubble out. Then add grain to mash tun?

Kind of like priming the transfer tube before i add the grains?

thanks for your input acasta,

Nath

 

[jyo]

I'm thinking that unless you are actually siphoning, a leak in the hose shouldn't make a difference...could be wrong though. The air pocket in the line is something that has shit me a few times too. A couple of 'full bore' turns of the tap for half a second blows it out though.
Maybe post a pic of your set up, mate.

 

[Tim F]

Just in the off chance, there's no way anything has got clogged up in your manifold is there? Does it flow freely if you just put water in the tun?

If that is flowing OK it has to be something to do with your grain/crush.

 

[bignath]

Just in the off chance, there's no way anything has got clogged up in your manifold is there? Does it flow freely if you just put water in the tun?

If that is flowing OK it has to be something to do with your grain/crush.

Definitely not clogged up manifold. Clear as a whistle..

I know it flows freely when i'm cleaning at the end of the day. I hook up the garden hose to the out tap and reverse flush the manifold, and then let it drain back out the tap. This works and flows very well, but i have to say i haven't as yet tried just water and using the hose as well. Will give this a go....

 

[Thirsty Boy]

You need to check a few things

As someone suggested - is your mash bed actually compacted? Instead of just "dumping" it, dig into it with a knife and look at a "slice" through it. See how its sitting around your manifold, is it really solid at certain points? is it loose and fluffy all the way through?

Are you getting a layer of fine stuff settling on top of your grain bed after you recirculate? If so it an kind of seal up the rain bed and cause it to suck down - poke holes in it. In fact thats a good way to check if its grain bed compactiong thats the issue. Give your grain bed a bit of a raking like it would get from lauter tun knives. Take a big arsed kitchen knife - at one point in your mash tun poke it all the way through to the bottom. Now grab it an inch or so short of full depth and cut your mash bed into a nice grid or diamond pattern with about 1 inch gaps between cuts. You arent disturbing the most important bottom inch or so of your grain bed and you allow liquid to more easily permeate your grain bed. You can even cut all the way down to your manifold without too much drama. If this gets things flowing, its a grain bed issue.

And take your hose completely off the mash tun, stick a bucket under the outlet and see what your flow rate is like through the tap with no more terminal gear on it...if its no good through the tap you know the problem is prior to that point.

I suspect your new bag of grain. If nothing else works - try doing either a protein rest on it, or if you are feeling really keen a beta glucan rest AND a protien rest, or if you are feeling really really keen... The beta and protien rest via a decoction. If that loosens it up, you probably just have a batch of sticky malt. Course it might be easier to just buy a brews worth of a different grain and see how that goes.

 

[real_beer]

I have pulled the mash tun apart and checked for blockages and cleaned it up nice 'n' good. Found nothing obstructing the flow.
I did however notice that a few clamps on the hose connecting the manifold to the back of the hosetail barb inside the esky were slightly loose. I tightened them back up maybe 1 complete turn with the screwdriver.

I am wondering, if there is any effect of suction or some other physics at play when using different length hoses in an enclosed vessel like a mash tun. I am also wondering if the slightest little hint of something loose can also screw around with suction/syphon type physics laws.



Nath

Hi Nath,

It could possibly be the actual hose inside your mash tun collapsing from the heat and weight of grain sitting on it.
If so the problem might be getting worse as the tube gets older & softer.
You could try inserting a few small stainless steel springs in the hose to support it & at least eliminate it as the cause.

Cheers

 

[bignath]

See how its sitting around your manifold, is it really solid at certain points? is it loose and fluffy all the way through?
Hmm, no idea of that one, will check this out next time i brew.

Are you getting a layer of fine stuff settling on top of your grain bed after you recirculate? If so it an kind of seal up the rain bed and cause it to suck down...
When i recirculated the first runnings (emptying mash of strike water), there wasn't any. Didn't pay any attention to looking for it either way - first or second runnings. Didn't get that far to see the grain bed on the second runnings. Gave up and went to bed. When i checked it in the morning, there was "fine stuff" grey in colour sitting on top of the spent grain. There always has been previously.

One thing i did notice, is that when i opened up the mash tun before recirculating, there was no water on top of the mash like there usually is. It already looked quite dry, even though i reckon i extracted somewhere between 15-20 litres out of the first runnings. I'm thinking this was due to the coarser crush with the mill first time use and maybe the husks soaked up more water???

And take your hose completely off the mash tun, stick a bucket under the outlet and see what your flow rate is like through the tap with no more terminal gear on it...if its no good through the tap you know the problem is prior to that point.
Will definitely try this one next time too...

I suspect your new bag of grain. If nothing else works - try doing either a protein rest on it, or if you are feeling really keen a beta glucan rest AND a protien rest, or if you are feeling really really keen... The beta and protien rest via a decoction.
Will look into this. I know what you mean by the terminology, just need to think the process through as to how i actually acheive it. If mash tun was a keggle, then it'd be easy, just gas fire it, but not sure about how to either utilise my immersion heater, or use water additions to ramp up temps. Will read up on methods...

If that loosens it up, you probably just have a batch of sticky malt.
Any idea if this is common or not?
I have never heard of it before, but i know you are a far more advanced brewer than i so i don't doubt it's possible.

It could possibly be the actual hose inside your mash tun collapsing from the heat and weight of grain sitting on it.
Nah it can't be that. Sorry should have been a little more specific. When i say i use some hose to get from manifold to back of hose tail barb, i mean that it's just used to bridge the two together. half of the short piece of hose is connected to the hose barb, and the manifold sits up hard against the barb inside the hose so there's no place for the hose to actually compact...

Another thing i've wondered since last night's postings, if i make my manifold bigger (more drainage points) is this likely to free up the problem, or make the problem worse? If my mash is prone to sticking at the moment, does having more points to drain from lessen the likelihood of a stuck sparge, or could it make it happen even easier?

At the moment, i just have a single length of copper tube running the length of the interior of the esky. I know it's not the greatest design and I know most people have a rectangular or squarish design with more lengths up the middle type thing, but mine has been working like this very well in the past and saw no reason to think about changing it's design until now.

Thanks for the thoughts guys, if any one has other ideas, please let me know...

cheers,

nath

 

[Acasta]

Got a picture of it? May help with some design issues for other to take a look.

 

[yardy]

Got a picture of it? May help with some design issues for other to take a look.

+1

 

[bignath]

Inside pic showing my mash tun copper tube outlet.




Esky is a square shaped coleman, taller than it is wide. The walls of the esky are just out of shot...

Yes i know it looks filthy in this photo, trust me, it's not as bad as it looks.

Yes i know it isn't the best design in the world, but as mentioned previously, has worked a treat for me in the past.

Copper tube touches the back of the hose tail, inside the tubing, so there's no chance of this compacting and stopping the flow.

There are slots cut in the underneath side of the pickup tube, and the end is crimped shut.

 

[bignath]

and here's the pic of the hose connector on the 1/2" all thread.

 

[Tim F]

that does look like a pretty small manifold. You said you used to get more cracks in the grain bed - I wonder if what's happening is you were getting channeling before you changed your grain/crush for whatever reason which meant wort was running straight through but now that this isn't happening any more, the small manifold isn't enough to drain quickly. If it was me my next step would be a bigger manifold - hose braid works for me and it's pretty cheap.

 

[mattyra]

Hi Nath,

Could it be that something has actually gone wrong in the tap only allowing it to open a certain amount.

I would try filling the mash tun with just water and see if it comes out normally. Its also a good way to make sure that it is most likely a grain issue.

 

[bignath]

Hi Nath,

Could it be that something has actually gone wrong in the tap only allowing it to open a certain amount.

I would try filling the mash tun with just water and see if it comes out normally. Its also a good way to make sure that it is most likely a grain issue.

Yep, checked it just now, both with the transfer hose attached and also without it. Flow's freely, uninhibited - great.

So does that mean it has to be a manifold or sticky grain issue?

I will build a "proper" manifold soon and see how i go. I was gonna do this years ago, but when this pickup tube worked for me i thought i'd leave it alone. Looks like it has some flaws...

The thing i still don't get though, is how come it's only been a problem now....

I'm ruling out the new mill, as it also happened on the last two batches with my previous mill which was left at factory gap setting. I opened up the gap setting on the new mill for first use as i thought that the previous two may have been due to a crush being too fine. It certainly was a lot coarser, but the problem with flow was identical as to before so i don't think it's the mill.

So, i'm heading toward either the grain (fresh bag for all three problematic batches) being more "sticky" as mentioned by TB, or the manifold. Therefore i will build a new manifold and try and rule that out....

Cheers, and if there are any more thoughts, i'd love to hear about them.

Nath

 

[dent]

A change in your water(seasonal)/mash pH can cause differences in how well your conversion occurs - if there is more starchy glue around than usual then it might be part of the problem.