Grain bed doughing up every few minutes.

[CafeRoaster]

Had my LHBS store mill up this batch, just like the last two brews. The mill is not adjustable. I'm using the same recipe and grains as the last two brews as well.

I noticed the pump starting to sound like a washing machine. I couldn't figure out what was happening, but finally saw that there was no liquid below the grain basket. Picked it up and nothing even trickled out. Put it back in, stirred up the grain bed, and it still barely trickled out. I texted my dad (much more experienced brewer). He said 3.7 gallons was not enough for 8.56 lbs for grains to mash with. I added 3 gallons, and it started working much better. I'm still mid-mash, and I'm having to break up the dough ball every five minutes!

Anyone know what's happening?

Attaching recipe and image of grain crush. Grainfather suggested 3.7 gallons to mash with, Brewfather suggest 4 gallons.

 

[Happy Tails Brewing]

I don't have a good answer for you. I like to mash in at a 1.5 qt per pound with .5 gal of deadspace. That is your 3.7 gallons. This is a pretty thin mash. You should have no issues with thickness. I think you had plenty of water. Your crush looks a little fine, but nothing that I would suspect would stop flow altogether. My best guess is that in doe in you didn’t fully let the grain absorb the water and mix well enough before you started to recirculate. With 6.7 gallons you should have water with a little bit of grain currently. Are you sure your water amounts are accurate? In you didn’t add as much at the beginning as you thought that could be your issue.

 

[Bobby_M]

What kind of brewing system is it exactly? Are you throttling the recirculation flow at all? You should be, just a trickle.

 

[hottpeper13]

Do you let the grains gelatinize before you start to recirc?

 

[CafeRoaster]

I don't have a good answer for you. I like to mash in at a 1.5 qt per pound with .5 gal of deadspace. That is your 3.7 gallons. This is a pretty thin mash. You should have no issues with thickness. I think you had plenty of water. Your crush looks a little fine, but nothing that I would suspect would stop flow altogether. My best guess is that in doe in you didn’t fully let the grain absorb the water and mix well enough before you started to recirculate. With 6.7 gallons you should have water with a little bit of grain currently. Are you sure your water amounts are accurate? In you didn’t add as much at the beginning as you thought that could be your issue.

Water amounts were accurate to the ounce.

What kind of brewing system is it exactly? Are you throttling the recirculation flow at all? You should be, just a trickle.

Oh, sorry! Modified Grainfather G30 - no overflow pipe, no top plate.

You know… I did not throttle the valve. Went wide open. Got more guidance on this in particular? Specifically, why and how to tell how much is enough?

Do you let the grains gelatinize before you start to recirc?

I don’t think I did! I did stir really well and had no clumping. Added all 8.56 lbs over the course of about 4 minutes, stirring with one hand and pouring the grains in with the other. Once they were all in, I stirred up a nice whirlpool. Then I immediately attached the recirc hose and started up the pump.

 

[jschein]

Oh, sorry! Modified Grainfather G30 - no overflow pipe, no top plate.

You know… I did not throttle the valve. Went wide open. Got more guidance on this in particular? Specifically, why and how to tell how much is enough?

I have a G30 also. Next time you brew fill the malt pipe with your grain and slowly lower it into the water. Let it sit a couple of minutes and recirculate slowly at first to set the grain bed

 

[hungupdown]

Compacted grain bed syndrome. Easily acheived by vigorous stirring, or by recirculating before the grain has hydrated.
Gently add grain to (submerged) malt pipe, with minimal stirring, just enough to break up dough balls without knocking off attached air bubbles.
The trapped air increases grain buoyancy, so gives a more open grain bed. Let the grain bed 'rest' for 10min to hydrate, and the swelling grains to 'lock' together, before starting recirculation. That forms your filter, don't destroy it by any stirrirg later.
Gradually increase recirculation rate, but back it off, if the wort level in the malt pipe ever rises more than 1/2 inch.

Without recirculation, levels inside and outside the malt pipe are the same, and its a 'floating' grain bed.
Recirculation generally causes some difference in wort levels between inside, and outside, the malt pipe,. Everything inside the malt pipe, that's above the outer level, is no longer 'floating', and it's weight is then resting on the grain bed.
If the outer level, ever drops below base of the malt pipe, then full weight of grain and mash water, rests on the bottom layer of grain. This is very likely to compact the grain bed.

Late stirring will also detach the previously trapped flour, which will likely then settle out on the base, and burn during boil (on an AIO system).

 

[Happy Tails Brewing]

Here is how I set my flow rate. I set my recirculation rate so that the volume doesn't rise. It will rise a little, but you want the wort inside the pipe and outside the pipe to be as close to the same level as possible. If I see the level in the pipe rising, I will shut the pump off for a little while for the levels to stabilize and maybe stir and then turn back on close the valve a litter bit. Then I watch and repeated. Once the flow is correct, I can walk away for a while. I try to make sure the level inside the pipe doesn’t rise by more than an inch. I always make sure i don't stir for the last 15 min of the mash so that the grain bed as a chance to filter the "flour" out before the boil. I also recirculate while I raise the temp for a mash out and then recirculate for 10 min once I get to temp. This seams to work for me.

 

[keystonehb]

Also for your all in one systems like the Grainfather it is recommended that you use some amount of rice hulls in every batch. Rice hulls do not at flavor or color but they help allow water to circulate through easier.

 

[VTMongoose]

Also for your all in one systems like the Grainfather it is recommended that you use some amount of rice hulls in every batch. Rice hulls do not at flavor or color but they help allow water to circulate through easier.

By any chance, have you ever tried pre-rinsing your rice hulls, and tasting the disgusting brown astringent water that results from doing so?

I always recommend pre-rinsing rice hulls. I was chasing astringency issues in my wheat beers for the better part of a year until this fixed it for me.

 

[keystonehb]

That is interesting. I have never heard anyone having an issue like that from rice hulls in the past nor have I noticed any myself.

 

[Jag75]

I use a Grainfather and dont use hulls on every brew . Only ones with wheat and oats .
When i do use , I don't rinse . Not even on a 3bbl batch

 

[hungupdown]

By any chance, have you ever tried pre-rinsing your rice hulls, and tasting the disgusting brown astringent water that results from doing so?

View attachment 875900

I always recommend pre-rinsing rice hulls. I was chasing astringency issues in my wheat beers for the better part of a year until this fixed it for me.

Have you tried pre-rinsing any whole grains, or oat husks, to compare what comes off?

That is interesting. I have never heard anyone having an issue like that from rice hulls in the past nor have I noticed any myself.

Have only used oat husks so far, and no astringency issues from these.
I used to taste astringency in many of my beers. But only sparging at 80°C or below (cooler towards the end) seems to have sorted that.

have a sack of rice hulls I'll be starting on soon. So maybe I should a pre-rinse comparison, with oat hulls, before using them.

I use a Grainfather and dont use hulls on every brew . Only ones with wheat and oats .
When i do use , I don't rinse . Not even on a 3bbl batch

I only usks/hulls in my BZ, for recipes with above about 30% wheat or Rye. I then add 10% husks, by weight (of the wheat /rye amount).

 

[VTMongoose]

Have you tried pre-rinsing any whole grains, or oat husks, to compare what comes off?

Nope. I have actually moved away from using rice hulls entirely on my recent brews as I have my system and mill dialed in to where I no longer have issues with mashes sticking during/after protease rests even with the 50-60% wheat beers I regularly produce.