Lauter Time is ridiculous!

[kai]

Mill works just fine and doesn't crush too much. I transfer from my mash cooker to the LT very slowly so I don't shear the grain and make it smaller allowing it to get stuck in the plates.

How do you slow your transfer from MT to LT?

VSD / VFD on the pump? Throttling back a valve on the outlet of a centrifugal pump?

Because the second will introduce more shear.

Just trying to look at something obvious that might be missed...

[kai]

I am confused as the the source of air bubbles under your screens. If you are underletting sufficiently, there should be no air pockets at the beginning of lauter. I suggest underletting at least 4" over your screens.

I experienced this once time in several years of brewing. It turned out to be a loose triclamp on the run-off pipes to the kettle (grantless brew house) letting air into the lauter during run-off. Coincedentally it was 60% wheat. Check everything for tightness (air tight, not just liquid tight), and insure a sufficient amount of water over the screens before pumping over from your mash.

In my experience, if you compact a bed hard enough then the pump will suck in air from somewhere... anywhere...

[kai]

Sparge & Runoff speeds get monitored very closely. I make sure that out=in.

Seems like the bed does a weird slow compaction over the course of half the kettle full volume (i.e. I get half of my start volume collected) and that's when I end up having to literally re-mix the whole mash (in the LT) and recirc. until ready to go again.

The LT has manometers on it so I can monitor liquid levels. It seems as the bed compacts more, the manometers keep dropping. It's like the bed is letting wort through somewhere, but overall liquid level drops to the point where it doesn't even register. Then, after the huge re-mix, manometers show near-full again, and then begin the slow drop. Compaction is a concern. No idea why it's happening. Fundamentally, I believe I'm doing everything right.

Thanks, and keep 'em coming.

Sorry for the triple post, but I keep rethinking.

If your manometers are behaving like that, then it sounds to me like no liquor is getting through the top part of the grain bed at all (ie not reaching the inlet of the upper manometer).

Since you are getting the bulk of your grain crushed by someone else, I would be inclined to worry about the quality of that crush, in particular the amount of fines present. A large amount of fines might well give you the problems you are experiencing.

Even in my homebrewing days I rarely trusted someone else to crush my grain for me...

[jwalts]

Tanner,

If you have mash mixers but not lauter rakes and you don't find any other problems, I'd try mixing only during mash-in (i.e. turn off the blades afterward and leave them off). I'd also do some trial-and-error to figure out how slowly you can run your mixing blades before your brewhouse efficiency begins to suffer. Having to mix during mashout may defeat the purpose of raising the temperature, so I'd try skipping that as well.

Could you reduce your vorlauf flowrate too? What's the diameter of your lauter tun?

Joe from down the road at Ale Asylum

[porter]

2 more things

What is your efficiency?

I find that with milling issues- especially when it's too fine, you have exceedingly high efficiency but a lot of problems with runoff.

Do you get a thick layer of that grey "peanut butter" that settles on top of the mash during the sparge?

Again- looking at how fine the grain is milled...

[Port Huron]

Hi Folks,

Thanks for the ideas. I'll be brewing tomorrow, and will see if I can see anything else that's obvious, or anything I haven't mentioned before. To answer a few of the latest questions:

-- Air -- Yes, I'll give all of the gaskets a check. Maybe that's an un-noticed problem.

-- Milling -- My base malt is pre-milled (we're just milling specialties on a small homebrew mill for a few more weeks). This has been a hot topic around the brewery lately. A lot of discussion has centered around the fact that the malt company might be milling too finely for our needs. I'm probably going to buy some screens to check, but the "peanut butter" layer is definitely there. The efficiency is always through the roof - 94% range. But the lauter time is almost not worth it.

-- Mash pump speed is controlled by VFD. Valves are wide open and speed of pump controlled.

-- JOE - The Mash mixer is just two large paddles - plenty of room below (so I'm hesitant to think they'd do a whole lot of shearing ???)
Question on the Mash-out -- My Mash Cooker is also my Brew Kettle. Steam jacket on both bottom and sides. If I didn't mix, wouldn't I be over-heating a good portion, just to achieve 168+ in the center?

-Vorlauf rate is slowed WAY down. Slower than the rate that I pump to kettle. LT to Kettle rate is around 1 BBL/ 8 Min. or more.

- LT Diameter is 6' and the grain bed rarely exceeds 12" high.

-- MANOMETER STUFF - if the liquor isn't reaching the upper manometer, where the heck is it going? There is always a visible amount of sparge water/wort on top of the grain, so I know I'm not drying the bed out. Is it sneaking out the side, and just dribbling to the bottom? I never keep much more than an inch or so of liquid above the grain, just to make sure I don't add any over-compaction with water weight.

I'll check a few things out tomorrow and give an update.

More Ideas always welcome! Thanks for everyone's help!!!!

Tanner

[jwalts]

Sorry, I meant that you try skipping the mashout altogether. Your lauter loading (grain weight divided by false bottom area) seems appropriate, so that shouldn't be a problem. Your manometer tubes won't necessarily measure your the liquid levels - their purpose is to measure the pressure differential between the top and bottom of the mash - so it doesn't surprise me that they get all wonky when your grainbeds compact.

Joe

[Matt Dog]

When I started on a new brewhouse many moons ago we had a similar problem. Somehow the VFD got messed with to the point that it transfered from the mash cooker to the lauter very slowly even at the highest setting. We talked to the guys that used to own it and determined we were transfering the mash too slow. We had to reset the VFD and a faster pump over solved our problem. Maybe your sending it over too slow and beating it up as a consequence?

[mmussen]

I'm not sure if this will help at all as I have a combi mash/lauter tun but the single biggest factor I've found in improving my run off times has been to thin out the overall mash. I don't know why that's what worked but I've managed to cut 20 to 30 min off my sparge times keeping my efficiency about the same (80ish %). It might be worth giving that a try

[Port Huron]

Solution Found! -- I think.

Folks,

Good News!

It seems that I've got a handle on the lautering problem/delay.

We had been using pre-milled base malt from our supplier. When we started out, we didn't have a commercial mill, and only milled our specialty grains in-house (to save time).

We got a new batch of malt in last week (whole), and fired up the commercial mill we recently purchased.

WHAT A DIFFERENCE!!! Lauter time was way down. It came in around an hour and 45 minutes. I've got to believe the milling was the difference. I had always wondered if the crush was way too fine on the pre-ground stuff. I think I was right. I'm able to set the crush just how I'd like it, and it's great.

If anything else pops up, I'll throw it out there, but we may be able to put this one to bed.

Thanks for all of the input!

Tanner
Port Huron Brewing Company
Wisconsin Dells, WI

[Beer_Nut]

Good. Glad to hear you got it sorted out. It definitely sounded to me like an issue with the grist.