Malt pipe issues with stuck mash

[Dubzie]

Hey lads,

I have a 82L brew pot with a 56L Malt pipe. The holes i have drilled are 2mm from memory


I have a recirculating system similar setup to qldkev with a mid return and a top return.
Old photo, i've since added a mid return and upgraded the pump.


I regularly brew a clone of Stone & Wood Pacific Ale which consists of 60% pale and 40% wheat.
I think that my LHBS mills the grain i get too fine (i think i remember him mentioning that it's set to 0.9 mm) and at this stage I cant afford my own mill and motor
Problem is because of the fine mill, bits of the wheat block the drilled holes and my mash gets stuck, the malt pipe fills up and ive nearly run the element dry on a few occasions, i literally have to scrape the bottom of the malt pipe to get any of the wort to drain once it gets stuck.

Any suggestions here?
More holes, bigger holes?

 

[crowmanz]

you tried rice hulls? throw a bunch in your mash in addition to the 60/40 pale/wheat and it should help preventing the stuck sparge/mash.

 

[n87]

Rice hulls?
There is also not a huge amount of holes there.

My setup (56L pot in 82L) i have punched 9 27mm holes in the bottom, and put a 30cm false bottom in.

Although i have a mill, and i widened the gap when i moved from bag to pipe

 

[evildrakey]

Rice hulls?

http://www.craftbrewer.com.au/shop/details.asp?PID=700

You use them as a neutral agent to add volume and loosen your Mash... But at 40% wheat, even with my Braumeister I'm add Rice Rulls to avoid a stuck run...

 

[QldKev]

I'd cut some slots in the base. Imho they work heaps better than round holes. Depending on the mill i don't think 0.9mm is too small. It is what I use both at home and also at work

 

[Dubzie]

Rice hulls?
There is also not a huge amount of holes there.

My setup (56L pot in 82L) i have punched 9 27mm holes in the bottom, and put a 30cm false bottom in.

Although i have a mill, and i widened the gap when i moved from bag to pipe

505 holes to be exact

What did you use for the false bottom?

 

[n87]

505 holes to be exact

What did you use for the false bottom?

Currently between bottoms. the first one I got didnt have enough open area for my liking (~7%)
Looking for something in the 20-50% range to hopfully aid in recirc. Waiting for a few shops to answer my questions... i will have to chase them up actually.

 

[Dubzie]

http://www.craftbrewer.com.au/shop/details.asp?PID=700

You use them as a neutral agent to add volume and loosen your Mash... But at 40% wheat, even with my Braumeister I'm add Rice Rulls to avoid a stuck run...

Yea i looked at rice hulls but because of how light they are they are expensive to ship, none of my LHBS stock them.

Edit:
There is a local place that sells them but in 125KG bags which is a HUGE amount

 

[n87]

I rekon go through with the bulk buy idea, you would get 25kg for about the price of a shipped 1kg bag.

 

[Dubzie]

Currently between bottoms. the first one I got didnt have enough open area for my liking (~7%)
Looking for something in the 20-50% range to hopfully aid in recirc. Waiting for a few shops to answer my questions... i will have to chase them up actually.

I thought about putting big holes in and using a false bottom myself, was thinking of using alu/ss fly screen as the gap is 2.1mm

 

[n87]

I thought about putting big holes in and using a false bottom myself, was thinking of using alu/ss fly screen as the gap is 2.1mm

interesting, however i would like it domed so you get a more even drain
I guess it depends on how many, and what size holes.

 

[Dubzie]

interesting, however i would like it domed so you get a more even drain
I guess it depends on how many, and what size holes.

Exactly, is there such thing as too much flow?
I guess i can experiment with this pot put some large holes like yours, try the Aluminium Flyscreen, and if they doesnt work out, resort to using a bag in the malt pipe till i can buy a new pot.

 

[n87]

You can always restrict the flow with the pump and how fast you pull the pipe out.

i have a hydraulic punch if you want to borrow it

 

[Dubzie]

You can always restrict the flow with the pump and how fast you pull the pipe out.

i have a hydraulic punch if you want to borrow it

I have a step drill bit, but i think i'll just use the largest drill bit i have and evenly space it in the current drilled pattern.

 

[MHB]

Mill Coarser - or get it milled properly
More holes - 505 X 2mm = 1,586.5mm^2, if your pipe is around 400mm in diameter 125,663.7mm^2. You only have 1.26% void, should be around 10% or more. Or cut slots, a 1mm SS cutting wheel is great.
Slow the pump down - Throttle on the outlet
Better design - if you work out the sizing properly the pipe will overflow before enough is pulled out of the kettle to expose the element. Quite likely if you adjust your batch size you can set it up to work that way with what you have. A top filter screen might work well in that case so too much malt doesn't floated off and into the kettle.
Mark

 

[Dubzie]

Mill Coarser - or get it milled properly
More holes - 505 X 2mm = 1,586.5mm^2, if your pipe is around 400mm in diameter 125,663.7mm^2. You only have 1.26% void, should be around 10% or more. Or cut slots, a 1mm SS cutting wheel is great.
Slow the pump down - Throttle on the outlet
Better design - if you work out the sizing properly the pipe will overflow before enough is pulled out of the kettle to expose the element. Quite likely if you adjust your batch size you can set it up to work that way with what you have. A top filter screen might work well in that case so too much malt doesn't floated off and into the kettle.
Mark

Math! I like it!

I do dial back the flow of the pump but it gets to a point no matter how much I dial it back it nearly stops draining all together, then i have to scrape the bottom of the pipe to dislodge the pieces of wheat stuck in most of the holes. I guess it starts off ok because the wheat just sits in the holes, but as soon as they start adsorbing some of the water and swelling up it blocks the holes.

Yea i thought of making an overflow hole, but i do single, double sometimes tipple batches in this rig so that wouldn't really work for me.

Might have to see if i can borrow a hand grinder and cut some slots in the bottom, see how that goes to start with.

 

[QldKev]

Also try setting the mash bed before trying to open up the flow. It makes a huge difference.

 

[Dubzie]

Also try setting the mash bed before trying to open up the flow. It makes a huge difference.

Didn't know about this.
I do usually just let it crank as soon as i've finished mixing in, I always wondered if the flow was too quick that could be causing the mash bed to compact.
Will also give this a try

 

[MastersBrewery]

When recirculating any HB system after mash in and mixing let it rest for 5min then start recirc at <1/3 pump throttle for 10min to set the bed. Then slowly throttle to wide open.