Constantly recirculating and still getting grain particulate in my kettle

[ryanj]

I'm 2 batches in with my new custom built E-HERMS system and this last batch was really smooth. I worked out a ton of issues I had with my first batch and was able to get record high efficiencies. BUT, there was one odd issue...

Let's start with some background info:

• Mashing in a 10 gallon cooler with domed false bottom.
• Grain is conditioned and mill is set to .035
• After dough in, I let my grainbed set for about 5 mins
• Constantly recirculating throughout the entire 60 min mash at about 2-3gpm
• After mash I do raise my temps to 170 and fly sparge for about 45 mins

Even though I'm recirculating throughout the entire mash process, and the the wort looks extremely clear, when I go to fly sparge, I'm seeing grain particulate passing through hose and into the boil kettle.

I didn't worry much about it, but it seems odd since I'm not disturbing the grain bed at all during the mash.

I figured I could back the mill down a bit or use a BIAB bag for another layer of protection. Anyone have any recommendations?

 

[Smellyglove]

It might be that you're recircing with a too high flow. So you're sort of "sucking" the tiniest particles through your grainbed. I know this has always happened in my setups if I recirculated with a too high flow. Or your grainbed is not thick enough to act as an (very) efficient filter.

2-3 gpm sound a bit high (for me). I calculated with 2.5 gallons for your example.

 

[Hwk-I-St8]

If everything is good while recirculating....no grain particles in the liquid that recirculating...then it sounds like and issue with the fly sparge. When you add sparge water to the mash while sparging, how is it added? Could you be disturbing the grain bed with the sparge water?

How was you efficiency? I ask because I think a disturbed grain bed would cause channeling and a loss of efficiency.

 

[Rodent]

I constantly recirc during my mash as well thanks to using a HERMS to adjust mashing temps when/as needed. I have a dome style false bottom in my Chapman tun, and the 'seal' around the bottom edge is near perfect against the bottom.

your 2-3 gallons/minute seems rather high IMO. my recirc rate is closer to 1/2 gallon/minute, and outside of an occasional grain particle my wort is grain free every time. I've pushed the recirc rate to over 1 gallon/minute without sucking any grain particles, but I seldom use this high of flow due to the large quantity of grains on the 2X IPAs and RISs I tend to brew most often

 

[ryanj]

If everything is good while recirculating....no grain particles in the liquid that recirculating...then it sounds like and issue with the fly sparge. When you add sparge water to the mash while sparging, how is it added? Could you be disturbing the grain bed with the sparge water?

How was you efficiency? I ask because I think a disturbed grain bed would cause channeling and a loss of efficiency.

I calculated an 88% mash efficiency. One of the best preboil gravities I've ever gotten. When fly sparging, I'm adding hot water from my HLT via a locline arm. I'm keeping 1-2" of water above the grainbed and when I'm done sparging, the grainbed looks immaculate. I'm PRETTY sure I'm not getting channeling.

 

[ryanj]

It might be that you're recircing with a too high flow. So you're sort of "sucking" the tiniest particles through your grainbed. I know this has always happened in my setups if I recirculated with a too high flow. Or your grainbed is not thick enough to act as an (very) efficient filter.

2-3 gpm sound a bit high (for me). I calculated with 2.5 gallons for your example.

I'm taking a wild guess on the flow rate. My pump is rated at 5-6gpm and I'm running it at about half speed during mash recirculation.

When I fly sparge, I turn it down as low as I can go (which ends up being about a 45min sparge).

You bring up "thickness" -- I've always mashed at 1.75qt/lb. I know that's considered "thin", but I always had decent luck in my batch sparge days with that mash thickness. Should I drop down to 1.25-1.5? Do you think that plus maybe a slightly slower recirculation will help?

Remember... the grain particles only start flowing when fly sparging at a VERY slow rate...not during mash recirc.

 

[Smellyglove]

I'm taking a wild guess on the flow rate. My pump is rated at 5-6gpm and I'm running it at about half speed during mash recirculation.

When I fly sparge, I turn it down as low as I can go (which ends up being about a 45min sparge).

You bring up "thickness" -- I've always mashed at 1.75qt/lb. I know that's considered "thin", but I always had decent luck in my batch sparge days with that mash thickness. Should I drop down to 1.25-1.5? Do you think that plus maybe a slightly slower recirculation will help?

Remember... the grain particles only start flowing when fly sparging at a VERY slow rate...not during mash recirc.

I didn't mean mash thickness, but the physical depth of the grainbed, sorry I was unclear.

How do you know the particles don't flow during mash recirc? Have you routed the locline to a glass or something to visually inspect?

If you have a thin grainbed, then you have less filtering. I'm seeing more dirty wort the less malt I use. Big bills are "crystal" clear, while the smaller beers do indeed have some particles in them, which sort of makes me cry when I see them.

Do the particles come during the entire time of the sparging, or maybe just at the end? I have to cut my draining a bit short, or else I'll pull gunk, but this is with an Infussion mash tun.

 

[mpmccann]

Honestly I have never had a grain-free finished wort into the boil kettle. I constantly recirculate through a rims setup but it is still the same principal. I also have a sight glass inline with the wort flow so I can see it better. I think you are always going to get some grains in there. How much grain are we talking about being left behind in your BK? If it is less than a table spoon full I would say that is probably par for the course. Now if you are talking about a half pound of grain then yes something is not right.
Also a slower re-circulation will most likely help, plus you will be less likely to have a stuck mash because you won't be compacting or sucking the grain down as tightly.

 

[ryanj]

I didn't mean mash thickness, but the physical depth of the grainbed, sorry I was unclear.

How do you know the particles don't flow during mash recirc? Have you routed the locline to a glass or something to visually inspect?

If you have a thin grainbed, then you have less filtering. I'm seeing more dirty wort the less malt I use. Big bills are "crystal" clear, while the smaller beers do indeed have some particles in them, which sort of makes me cry when I see them.

Do the particles come during the entire time of the sparging, or maybe just at the end? I have to cut my draining a bit short, or else I'll pull gunk, but this is with an Infussion mash tun.

I use the clear high temp silicone hose from BargainFittings and I can see them trickling down as I sparge. The particles appear to flow throughout the whole sparging process. It's not a lot, but it's really frustrating to watch after I know I just spent an hour recirculating absolutely clear wort.

It's just so weird because there's no difference in my MT when recirculating vs sparging. The ball valve is wide open and I'm limiting the flow at the pump different. Mash recirc = 1/3-1/2 flow and Sparge = the lowest I can flow while still moving wort.

 

[ryanj]

Honestly I have never had a grain-free finished wort into the boil kettle. I constantly recirculate through a rims setup but it is still the same principal. I also have a sight glass inline with the wort flow so I can see it better. I think you are always going to get some grains in there. How much grain are we talking about being left behind in your BK? If it is less than a table spoon full I would say that is probably par for the course. Now if you are talking about a half pound of grain then yes something is not right.
Also a slower re-circulation will most likely help, plus you will be less likely to have a stuck mash because you won't be compacting or sucking the grain down as tightly.

It's tough to say how much made it into the BK. A lot of the particles got caught up in the "loop" I created with the hose. The particles settled at a low spot and then since the pump was turned all the way down, the flow was slow enough to keep them there.

If I had to guess, probably about a tablespoon or so. This was a 10.5lb grain bill (kind of small), so maybe it was just specific to the bill size?

Either way, I'm 100% positive I didn't have any channeling or bed compacting. After my fly sparge, the bed was immaculate and nice a soft (not all dense like it had been in previous batch sparge batches).

 

[Smellyglove]

I use the clear high temp silicone hose from BargainFittings and I can see them trickling down as I sparge. The particles appear to flow throughout the whole sparging process. It's not a lot, but it's really frustrating to watch after I know I just spent an hour recirculating absolutely clear wort.

It's just so weird because there's no difference in my MT when recirculating vs sparging. The ball valve is wide open and I'm limiting the flow at the pump different. Mash recirc = 1/3-1/2 flow and Sparge = the lowest I can flow while still moving wort.

But when recirculating you have a much higher flow, can it be that particules are flowing too fast for your eye to catch?
You haven't mentioned this, so I guess you haven't noticed if it happens. Do you turn off your pump between mashout and sparging? If you do, and if you're recirculating with a too high flow, you will suck air which can get trapped under your dome, or just in between in the grainbed. If you shut your pump off, that air is not being "pulled" any more, and will rise to the surface messing up your grainbed. This has happened to me several times. Then the wort will get dirty when you transfer to the BK.

 

[ryanj]

But when recirculating you have a much higher flow, can it be that particules are flowing too fast for your eye to catch?
You haven't mentioned this, so I guess you haven't noticed if it happens. Do you turn off your pump between mashout and sparging? If you do, and if you're recirculating with a too high flow, you will suck air which can get trapped under your dome, or just in between in the grainbed. If you shut your pump off, that air is not being "pulled" any more, and will rise to the surface messing up your grainbed. This has happened to me several times. Then the wort will get dirty when you transfer to the BK.

Interesting. I am turning my pump off between mashout and sparging since I need to swap hoses. Are you suggesting keeping the pump on and just closing the ball-valve on the pump "outlet"?

I don't *think* I'm recirculating too fast, but I can always dial it back a bit more. I'm using one of these pumps: https://www.aliexpress.com/item/Hig...tainless-Steel-Head-Homebrew/32793792417.html and dial the flow back to about 1/3-1/2 with the ball valve.

 

[Smellyglove]

Interesting. I am turning my pump off between mashout and sparging since I need to swap hoses. Are you suggesting keeping the pump on and just closing the ball-valve on the pump "outlet"?

I don't *think* I'm recirculating too fast, but I can always dial it back a bit more. I'm using one of these pumps: https://www.aliexpress.com/item/Hig...tainless-Steel-Head-Homebrew/32793792417.html and dial the flow back to about 1/3-1/2 with the ball valve.

If this is actually happening then no, don't keep the pump on, but dial back flow to match your grainbed and false bottom. It might flow freely without compacting, but when you're operating at the very limits of your false bottom and grainbed throughput, air is sucked in before you get noticable compacting. This is at least my experience. It might seem "fine", but some times after I shut down the pump to rearrange hoses, lots of air is surfacing from the grainbed, basically rendering it useless for filtration during lautering. Also too much flow will cause some channeling, which will not filter particles out in the channels.

Either way:

What I'd look for is:
Not deep enough grainbed, so it's not filtering satisfactory.
Too much flow.

I believe I said this in the other thread you made about the compacting issue you had a few weeks back. If you stick you mash paddle down there it should be more or less equal density throughout the grainbed. It should feel like you're stirring in spaghetti (great description @Yooper)

 

[Smellyglove]

Interesting. I am turning my pump off between mashout and sparging since I need to swap hoses. Are you suggesting keeping the pump on and just closing the ball-valve on the pump "outlet"?

I don't *think* I'm recirculating too fast, but I can always dial it back a bit more. I'm using one of these pumps: https://www.aliexpress.com/item/Hig...tainless-Steel-Head-Homebrew/32793792417.html and dial the flow back to about 1/3-1/2 with the ball valve.

You should route your locline into a jar you use for measurment and use a stopclock/timer function and see what your rate is actually at. Just let it flow for 15 seconds and multiply by four to get your pr minute flowrate. then you can mark your valve with the setting. Although flowrate varies with gristsize and grist composition (flaked, wheat, etc), but can mark with flowrate @ x pounds of grain. You can use different colored markers for instance to indicate a range of gristsizes.

For instance: Red marker can indicate between 4-6kg of grains, green marker indicates 6-8 kg of grains etc. Use tape on both parts of your ball valve, align lines and mark the tape.

 

[ryanj]

If this is actually happening then no, don't keep the pump on, but dial back flow to match your grainbed and false bottom. It might flow freely without compacting, but when you're operating at the very limits of your false bottom and grainbed throughput, air is sucked in before you get noticable compacting. This is at least my experience. It might seem "fine", but some times after I shut down the pump to rearrange hoses, lots of air is surfacing from the grainbed, basically rendering it useless for filtration during lautering. Also too much flow will cause some channeling, which will not filter particles out in the channels.

Either way:

What I'd look for is:
Not deep enough grainbed, so it's not filtering satisfactory.
Too much flow.

Roger that -- I'll dial back the pump even further and see if that solves my problem. From what I understand, the speed of recirculation has no real effect on the overall quality of the final product, so no point in pushing it.

...right?

 

[Smellyglove]

Roger that -- I'll dial back the pump even further and see if that solves my problem. From what I understand, the speed of recirculation has no real effect on the overall quality of the final product, so no point in pushing it.

...right?

Absolutely correct. The recirculation is just to maintain mash temps, aid in some efficiency and filter the wort. If it's not filtering correctly then only two of three positives are present.

 

[Smellyglove]

If you feel that you have to dial it bac down to under what is stated as "standard" (1C increase pr minute) during step mashing you have the option of just going with your flow and adjust your mashing regime accordingly.

Just figure out what works for you, and brew in harmony with your setup