Hi everyone,
Last year I implemented a reciculating mash system to try to get clear wort into the kettle. I’ve had marginal success with it but it’s been inconsistent and I’ve also had lower than my normal efficiency.
After running off to the kettle I’ve noticed that the grain bed is somewhat pulled away from the sides of the mash tun and seems to be somewhat compacted, leading me to think maybe I’m running the pump too fast, even though I have had this happen when cutting back the flow as low as I can from the beginning. I’ve tried stirring at intervals in the mash to uncompact the grain bed. So I’m installing a manometer composed of 2 weldless sight glasses, one above the false bottom and one below, with hope that I can see what is going on and be able to make adjustments from there.
Where exactly, in relation to the false bottom and pump, should I install the sight glasses? What should I look for when using it? Any other insight on getting clear wort into the kettle?
I brew 5.5 gallon batches, full volume mash, in a 15 gallon direct fired tun. Slotted false bottom sits about 3" above the bottom on a rack made of 3" wide SS sheet metal pieces that go together vertically in a tic tac toe type of grid. I pump into the water on top of the grain through a piece of locline with the outlet just under the surface. I condition my grain just before milling leaving the husks intact after milling. Mill gap is about .035 and Mill runs at 120 rpm.
Thanks in advance for your comments.
I am not really sure that you need two sight glasses. From my pro-brewing days, we had a manometer installed at the outlet of the mash/lauter tun and could see if the if the runoff was getting stuck by watching the change in the height of the liquid in the tube. When it started dropping, we slowed the runoff rate.
I may be a bit off base here but I don’t think that the extra sight glass on top of the false bottom will buy you anything.
Thanks for your response, goose. I’m using the double sight glass setup in trying to emulate the manometer on the SS brewtech 20 gallon mash tun. I can’t seem to find much info on manometers on the homebrew level.
You want one below the false bottom and one above it. When the one above the false bottom starts to go down you will need to slow your pump speed or run off. You might also have luck not grinding so fine.
Thanks. So an inch above and below the false bottom? Half inch? Not important?
I recently got a new Mill and I’m still working on determining the best crush for my system.
Personally I don’t think it’s all that important. I recirc to remove the big particles, but then run it off. Hasn’t seemed to make a difference in the clarity or longevity of my finished beers. YMMV of course.
Anyway, you probably have too much flour, i.e. you’re milling the grain too finely. The fine flour particles as well as proteins and lipids from the grain collect as gunk top of the grain bed and form a thin but impenetrable layer called obertieg (or just tieg), which prevents water from percolating through the grain. So the water takes the path of least resistance, which is down the sidewall instead of through the grain. The grain pulls (or is pushed?) away from the wall and efficiency suffers, because you’re running off mostly water. You may not be running the pump fast, but it is indeed too fast relative to the (low) permeability of the grain bed.
Gently raking/cutting through the top layer of the grain bed during runoff helps a lot with this. I use a simple butter knife. Only need to cut ~1 inch (or even less) deep. The idea is to prevent the tieg from forming. Making your grind coarser will also help.
I don’t really see how the manometers will help you here. It’s a process issue, not a measurement issue. But you do want that second manometer immediately above the false bottom, as close to it as possible. Cheers.
Actually, this was my answer, too, but I withheld figuring I’d get yelled at! But, don’t worry about clear wort. I have never found any difference in the finished beer between a clear runoff and a cloudy one. If it was me, my inherent pragmatism would say "why are you going to so much effort to do something that doesn’t matter. Of course, your own decision is up to you.
Good info RC. You hit on my goals there with the comment on longevity. I tend to brew intensively but intermittently. I’ll brew many consecutive batches until my kegs are full and then get busy with something else for a few months. So shelf life is important to me and if clear wort helps meet that goal, I’m all in.
I’ll try opening up the mill to .040 and see if that helps.
As far as cutting the obertieg, I’ve tried that. But since I am doing a full volume mash, the top of the grain is under several inches of liquid so I can’t even see it to know if I’m doing it right. But I’ll keep trying it.
Another thing I’ve been doing is starting the recirculation immediately. I wonder if I should let things settle first?
But does clear wort help with that goal? Not trying to start an argument, but I haven’t seen any evidence that it does.
Denny, I’m just trying to take the advice of Kunze: Cloudy lautering and poor trub excretion lead to large amounts of free fatty acids in the wort, which the yeast cells require to produce new cell substances, but which can also contribute to a reduction in flavour stability.
Also, if the grain bed is compacting and somewhat collapsing towards the center so that the wort is going around the grain bed instead of through it, then my efficiency takes a big hit, which is frustrating to me. I know, throw in an extra pound of grain. But I get great pleasure in designing and building a system and seeing it work as intended.
Now we’re talkin!
Whether it makes a difference or not, as a result of recirculating throughout the mash, I get crystal clear wort in the boil kettle. …and I like it!
If you enjoy it, do it. I go by my experience, and I hate building equipment!
Cloudy wort distracts me from my flow state on brew day.
Not to further the debate about the utility of a long vorlauf, but a long vorlauf is the culprit behind the teig–and therefore it’s ultimately behind the grain compaction and low efficiency you’re experiencing. You’re taking the very fine particles that get through the false bottom and depositing them on top of the bed, where they accumulate. Longer vorlauf = more accumulation. So cutting the teig becomes more important with a long vorlauf.
Do you also do protein rests? They cause a ton of teig. But we’ll save protein rests for another thread 
For cutting the teig, I would just dip in a long spoon until you feel a little resistance, then go a tiny bit deeper and start gently raking. No visual necessary. But a coarser crush alone might fully solve your problem.
Good info, RC. I shall cut the teig and crush coarser to reduce the amount of flour.
An alternative to knifing the top dough (that’s English for Oberteig) is to just take your spoon and gently stir up the top inch or so of the grain bed into the liquid. It will settle with the protein sludge more dispersed through the material instead of as a solid cap.
As Rob just pointed out, cutting the top dough, oberteig, or schmutzedecke is not the way to go. It violates every principal of flow through granular media to just “cut” the layer. What good is cutting a thin groove in the layer going to do in comparison to dispersing and trapping that doughy material within the upper portion of the grain bed???
A manometer is only needed below the false bottom or at the bottom of the tun. Two manometers are not needed. The most important thing that I’ve found in the almost 20 years of brewing with a manometer-equipped tun, is to NOT allow too much drawdown to EVER be applied to the grainbed. In my experience, you don’t want to draw down the head level at the bottom of the bed any lower that the bottom of the bed. When using a pump, you can impose a suction on the bottom of the bed that is several feet below the bottom of the bed. That is way too much suction and that will compact the bed. Monitoring and limiting the drawdown is the best way to avoid compacting the bed.
Regarding the “grain pulling away from the walls”, what sort of false bottom is in that tun? It sounds like the center of the false bottom is collapsing.
Why does my wife’s manometer read zero around me?
Ha! I didn’t even think of that.
It’s a flat, slotted false bottom that sits on a 5 x 3 tic tac toe type of grid. It’s extremely sturdy. I could easily stand on it when it’s installed in the tun. Sorry, I can’t seem to attach a link or picture.
So if I install a single manometer below the false bottom, what will it look like during optimal flow vs. excessive flow?