Mash recirculation huge divot in grain

[itivino]

Recirculating in the mash with just a tube, similar to Kal's setup, I quickly get a huge divot in the grain where the recirc tube outlet is, almost all the way down to the false bottom (roughly 8 inches). Going to use a pic from Kal's setup - the divot would be in the 7pm position (at the end of the recirc tube), V shaped and about 6 inches deep.

Does everyone get that with this type of re-circulation arm/tube ? Is it creating one big channel that kills efficiency? If so, is it best to live with it and stir ever once in a while during the mash? And if so, stir only the "top" of the grain and avoid the bottom grain bed?

More details on my setup: RIMs, re-circulating at 1gpm (though the above still happens at slower speeds), chugger pump, 30 gallon kettle, false bottom. I've tried changing the location of the end of the tube and the divot forms wherever the output of the tube is.

 

[orangehero]

So what is your efficiency?

 

[itivino]

So what is your efficiency?

It's a bit inconsistent - anywhere between 65% and 80%.

 

[bobeer]

I brew at my LHBS on their Blichmann easy brew sometimes and I have to slow down the flow rate of the circulation to stop that from happening. It it's coming out of the pump too fast I get the grain moving around and I also get the hole you're speaking of.
Getting the flow rates all locked in takes me forever. I'm either losing too much in the mash, not having enough water in the HLT or not pumping fast enough to make the pump happy. I find getting the flow right and doing a mashout really helps my efficiency.

 

[itivino]

I brew at my LHBS on their Blichmann easy brew sometimes and I have to slow down the flow rate of the circulation to stop that from happening. It it's coming out of the pump too fast I get the grain moving around and I also get the hole you're speaking of.
Getting the flow rates all locked in takes me forever. I'm either losing too much in the mash, not having enough water in the HLT or not pumping fast enough to make the pump happy. I find getting the flow right and doing a mashout really helps my efficiency.

Kettles and Grains ? Brew Loco ?

Yeah, that does seem to help, though we still get the digging even at sparge speeds of 1qt/min on ours. Am thinking of getting a flow meter for the consistency and testing of different flows. Amazed that Kal's doesn't cause this, watching his videos he seems to re-circ at a really high speed, 2gpm+ (at least visually, the whirlpool looks that fast).

 

[bobeer]

Kettles and Grains ? Brew Loco ?

Yeah, that does seem to help, though we still get the digging even at sparge speeds of 1qt/min on ours. Am thinking of getting a flow meter for the consistency and testing of different flows. Amazed that Kal's doesn't cause this, watching his videos he seems to re-circ at a really high speed, 2gpm+ (at least visually, the whirlpool looks that fast).

Brew Loco. K&G is too expensive. George is a great guy but I can find pretty much everything he sells cheaper else where.

When I brew on the Brew Easy at the shop I try to lay the hose on the side instead of it facing downwards. I'm sure you've tried this but the flow seems to rush over the grain bed and cause a whirlpool. Maybe try playing with the speed of the line-out from the mash? Maybe you're having the wort leave too quickly? Like I said in my first response this part of the brew process isn't as easy as the Blichmann name suggests in their "Brew Easy" name for the product. This easily adds an hour to my brew day...
Let me know what you try and what you come across. I'm interested to maybe apply some of your techniques for helping my own process on that system.

 

[thereverendmaynard]

I have the same issue. I have thought about cutting some slits in the hose to lower the flow rate out the end of it.

 

[itivino]

One thing Cathy says she tries is to lay the recirc tube over the sparge arm on the blichmann so the wort runs down the sides of the pot, though she says it still causes the issue.

I do lay mine on the top like the pic above, I've tried restricting the hose and increasing the flow to get more horizontal force, but that doesn't seem to help either.

I may try your suggestion of slowing down the flow out of the mash, though I've always been careful of restricting the flow before the chugger pump. I could do that if I used a grant though, similar to the blichmann.

Worse comes to worse, may just lay down some aluminium foil across the entire mash, or stir it every few mins. Or maybe I'm making too big a deal out of a divot, but it seems to me like it would cause massive channeling.

The slits I'm sure would help too - though even the smallest flow causes divots in our system.

 

[Stillraining]

Could you guys lay a false bottom screen on the grain bed and let it filter down through that.?

 

[kal]

When you posted this on my forum you mentioned having milled at 0.039" gap setting.

I suggest milling around .050" gap setting (looser).

If you mill too fine, it'll cause flow restrictions which will in turn make the wort dig into the grain to find a way through.

One way to tell that you're having flow problems through the grain is to close the pump all the way and then open it quickly all the way and see if your sight glass level drops a lot. If it does, your grain bed doesn't have good flow.

Kal

 

[kal]

Forgot to ask: What kettles and false bottom are you using? I was assuming Blichmann but if you've got some other false bottom / kettle combo that causes side wall shunting then that could exacerbate the issue as well.

Kal

 

[pretzelb]

When you posted this on my forum you mentioned having milled at 0.039" gap setting.

I suggest milling around .050" gap setting (looser).

If you mill too fine, it'll cause flow restrictions which will in turn make the wort dig into the grain to find a way through.

One way to tell that you're having flow problems through the grain is to close the pump all the way and then open it quickly all the way and see if your sight glass level drops a lot. If it does, your grain bed doesn't have good flow.

Kal

Does the .050 gap assume conditioning the grain first?

 

[kal]

Does the .050 gap assume conditioning the grain first?

Nope!

Kal

 

[pretzelb]

Nope!

Kal

So then I assume you've changed from the .045 gap you wrote about on the site. Was there a test you did to explain the change?

 

[thereverendmaynard]

So Kal - at .05 you dont see any divot on the side where the hose outlet is? Is this when you are running your pumps at full flow?

 

[itivino]

So Kal - at .05 you dont see any divot on the side where the hose outlet is? Is this when you are running your pumps at full flow?

To add to the question, full open I think can vary wildly (at least on my own system) depending on hose length and RIMs vs. HERMs. A fully opened 1/2 ball valve on HERMs may be 2gpm but on a much shorter RIMs it could be 6gpm.

 

[kal]

So then I assume you've changed from the .045 gap you wrote about on the site. Was there a test you did to explain the change?

The 0.045" gap size recommendation in my grain mill article are for people building my setup as documented, with the parts I recommend (in this case the important parts are the kettle/false bottom/hoses/pumps I recommend).

I'm recommending itivino try 0.050" because (a) he's not using the same false bottom and (b) 0.039" isn't working for him. (.045" wouldn't be much of a change). On my setup I've tried from 0.040" to 0.050" and have not noticed any difference. Using a different setup may give different results.

So Kal - at .05 you dont see any divot on the side where the hose outlet is? Is this when you are running your pumps at full flow?

I see a bit, maybe a 1-2" depression. I run both my MLT and HLT pumps open 100% during mashing. I slow them down during sparging of course.

For complete details on my brewing process, see my BREW DAY STEP BY STEP article. There may be other things I do differently too, and without asking 1000 questions you'd never know what's different.

To add to the question, full open I think can vary wildly (at least on my own system) depending on hose length and RIMs vs. HERMs. A fully opened 1/2 ball valve on HERMs may be 2gpm but on a much shorter RIMs it could be 6gpm.

Yup. Would also depend on the pumps and false bottom too. Pretty much anything that the fluid has contact with would/can affect flow.

Kal

 

[BudgetBrewer]

I have had the same issue... Im using keggles, Silicone hose such as yours thru 45' of 1/2" rims tube with a chugger. I found just slowing the flow down a bit, keeping a bit more water on top of the grain bed helped... Seemed to spread it out, not so concentrated of flow close to hose outlet. I still get some divot but still getting around 85% efficiency...

 

[BudgetBrewer]

Currently enjoying an unfiltered Falconers Flight from the system. Really tasty. Gonna haveta brew again...

View attachment 1463091722192.jpg

 

[thereverendmaynard]

http://www.ssbrewtech.com/products/re-circulation-manifold-for-infussion-mash-tuns?lssrc=related

Just saw this on ssbrewtech. Looks like it would solve this problem.

 

[SlanginDueces]

I built an exact copy of Kal's system and also recirculate with the valves full open and have never had this issue. I do not even really see a divot at all to be honest. My efficiency is dead on 85% every time.

 

[thereverendmaynard]

My kettles/false bottom/pumps and hoses are the same as Kals, and I get a pretty good size divot at the hose outlet. I am going to try increasing my crush size - im at factory default 039 right now, and i think the HBS are also pretty tight as well. I ordered that SSBrewtech thing i posted above so will give that a go as well (i think that will resolve it). I am running in the low 80's efficiency as well on my last few brews.

 

[itivino]

By fully open, is that a full 7 gallons per minute or more like 1.5 gpm ?

 

[SlanginDueces]

Not sure what the gpm is but I use March pumps and have the valves completely open

 

[itsnotrequired]

My kettles/false bottom/pumps and hoses are the same as Kals, and I get a pretty good size divot at the hose outlet. I am going to try increasing my crush size - im at factory default 039 right now, and i think the HBS are also pretty tight as well. I ordered that SSBrewtech thing i posted above so will give that a go as well (i think that will resolve it). I am running in the low 80's efficiency as well on my last few brews.

did you order the ssbrewtech manifold? have you tried it out?

 

[thereverendmaynard]

Yup. I have used it 3 times now. No more divot. Works great.

 

[itsnotrequired]

Yup. I have used it 3 times now. No more divot. Works great.

have you noticed increased efficiency?

 

[thereverendmaynard]

I have only 7 AG brews under my belt - and I am running low 80's for mash efficiency.... haven't really noticed a big difference... maybe a couple % points, but this is not a very scientific measure....