Vacuum breaker on MLT for setting recirculation flow rate

[Truman42]

Well I finally solved my stuck mash issues. Turns out it was just my drill crushing the grains too fine even though I tried to run it as slow as possible. I ended up adding a wiper motor to my mill which at a grain mill gap setting of 1mm gave me a perfect crush.
It took 15 mins to crush my grain but I measured my salt additions and did other things while it was milling away happily.

My efficiency went from 62% to 82%which I was very happy about. I would have been happy with 70% so to get 82% is bloody awesome. I ran the re circulation with the valve set at 3/4s open with no stuck mash at all so next time will open it right up.

I must admit it feels great when you finally solve a problem that's been plaguing you for awhile now.

Here's my new mill motor setup



And here is the crush I'm getting. Looks spot on to me. The husks have opened up to release their goodness but are still in tact enough to create a nice filter bed.

 

[Yob]

What was your flow rate?

 

[Truman42]

What was your flow rate?

With the tap at 3/4 I got around 3 litres per minute on my last brew. Fully open about 5 litres per min but I was reluctant to keep it fully open for fear of getting another stuck mash. But next time I will go full throttle.

 

[Yob]

Don't live in fear man

 

[Camo6]

Great stuff Troy. That buggers even uglier than my setup! Good idea with the pc supply. I've got one from an Apple desktop I'd planned to use but it's a bit bulky, and the 4wd battery I'm using hasn't needed recharging for over a year and a half. What voltage and amperage is that sucker? I think I've got one from an old laptop somewhere.

Lol @ Yob. Do it man, let er rip.

 

[Truman42]

Yeh ugly is the word... It's actually a down light transformer. Converts 240 v to 12v AC then the square terminal thingy is a bridge rectifier to convert the 12v AC to DC. Not sure how many amps though and I'm not at home ATM. The motor only spins at around 50 RPM so quite slow but there is always something to do whilst I'm milling anyway.

 

[Camo6]

Nice work, never considered that. Mines about the same rpm. Turn it on and walk away. Weigh out salts, measure out hops etc, etc. My crush has minimal flour and keeps a lot of whole grains that fall apart with a gentle pinch. My only problem is my hopper holds more than the receiving vessel and I keep forgetting to buy a bigger bucket! Good to see you've cracked your problem. 82% is great!

Edit: (cracked pun not intended but I'll take it)

 

[KillerRx4]

I built a Vacuum break into my MLT plumbing after rigging it for recirculated mashing. It helps easily identify a compacting bed enabling me to cut the bed if necessary to prevent a stuck recirculation & also prevents it from crushing the false bottom in a high vacuum situation. This happened once on on a large mash with some notoriously sticky malts.

Pic attached.