HERMS – fly sparge 65% efficiency

[MikeSkril]

Hi there!

I used to bath sparge with a cooler and copper manifold with an efficiency around 75%. I moved over to a 10gal SS Brewtech mashtun and my efficacy moved up to 80%.
Now I’m using the SS Brewtech tun within a 3 vessel HERMS system (HLT,MLT,Boil kettle) and I’m getting a brewhouse efficiency of 64%. (my process is pretty much the same as the Electric Brewery)

- The crush has not changed, so I assume that’s not the issue.

- I recirculate thru the coil in the HLT for the whole mash time of 1 hour. Recirculation creates a little whirlpool on the top of the grain bed and the bed is not compacted. The wort circulates very well and I’m sure that there is no channeling.

- I fly sparge for around 40 minutes. The sparge water flows in slowly, not creating a whirlpool on top of the grain bed. Could channeling be the issue?
I sparge till I have 8 gal in the boil kettle. Should I stop before to have less water in the mash tun?

The volumes are not off. I collect 8 gal pre-boil, 1.5 gal boil off, 6 gal into the fermenter.
I did only measure OG when the boil was over, so I don’t know final run off OG.

What do you think?

 

[doug293cz]

Have you done a batch sparge on the current configuration of you system? If not I suggest you try that. If that comes out at the efficiency you used to get, then you know that your fly sparging process is to blame. The most common cause of poor lauter efficiency when fly sparging is channeling.

Brew on

 

[processhead]

It sounds pretty basic, but have you confirmed you are hitting your mash out temperature in the grain bed prior to the runoff?

Low mash out temps = reduced efficiency.
Likewise for low sparge water temp.

 

[LarMoeCur]

If I were you, I'd start taking reading of what is coming out of my mash tun and what is in the boil kettle. I start to monitor wort gravity right about 2 gallons before my the final boil volume. Mainly because I don't want to extract tannins (sparging below 1.010). And, I know if I need to adjust my boil volume to hit my numbers. I'd bet your leaving wort behind in the Mash tun. I can't see you getting less efficient with a recirculating system.

Do you do a mash out? What is the temperature of your sparge water? Do use a sparge arm or just a hose laying on the grain bed? I'm assuming you are using a false bottom in the MLT.

 

[ballz50401]

Be sure to double check your temps with multiple thermometers.

I usually wait about 5-10 minutes after I mash in before I vorlauf and start to recirculate through my HERMS coil. This helps set the grain bed and prevents it from being compacted. I also stir the mash halfway through the sac rest and again let it rest 5-10 minutes before I start the pump back up. This helps equalize the mash temps.

I usually get around 80% efficiency for average gravity brews.

 

[doug293cz]

It sounds pretty basic, but have you confirmed you are hitting your mash out temperature in the grain bed prior to the runoff?

Low mash out temps = reduced efficiency.
Likewise for low sparge water temp.

I disagree. Mash out only affects efficiency if the conversion was incomplete at the end of the allotted mash time. If that is the case, then the mash out improves efficiency by extending the mash time to get more conversion, and increasing the rate of conversion (until the enzymes are totally denatured.) Mash out, and mash out temperature have no effect on lauter efficiency.

It has been shown that sparge water temp has no effect on batch sparge lauter efficiency (ref.) It's plausible that water temp might have an effect on fly sparge efficiency, but the theory of why there would be an effect also indicates it would be a minor affect. I'm not aware of any experimental data that demonstrates an actual effect. Are you aware of any?

Brew on

 

[MikeSkril]

Thanks for the comments!

Some additional info:
- I dont do a mash out but the mash time will rise till I hit sparge temp in the HLT
- I dont use a sparge arm
- I sparge with 168F water but that will drop a little over time
- I've used a few thermometers to be sure about the temperatures
- The Barley Crusher 0.039 gap
It's basically the same process as The Electric Brewery uses.

That's what I'm gonna do:

- get a refractometer and measure multiple times during the whole process
- try one batch using batch sparging to see if the issue is not related to the fly sparging

I don't think that the recirculation is compacting the grain bed. I'm getting a good flow and the wort runs clear after 10 minutes or so.

 

[mirthfuldragon]

I am wondering if you are leaving sugar in suspension with the fly sparge continuing for the duration. How much more wort will continue to drain off once you stop the fly sparge? In other words, stop the fly sparge at 7 gallons (+/-) and let the mash tun drain out.

What I am wondering is that the sparge water is passing through without picking up much if any sugar. Imagine a bucket of water with some red dye in it, and as you fly sparge, the water coming out is red and the water in the bucket is red- it keeps getting lighter red, but is still red. If you stop adding water and let it drain, then all the red water will drain out of the bucket.

 

[processhead]

I disagree. Mash out only affects efficiency if the conversion was incomplete at the end of the allotted mash time. If that is the case, then the mash out improves efficiency by extending the mash time to get more conversion, and increasing the rate of conversion (until the enzymes are totally denatured.) Mash out, and mash out temperature have no effect on lauter efficiency.

It has been shown that sparge water temp has no effect on batch sparge lauter efficiency (ref.) It's plausible that water temp might have an effect on fly sparge efficiency, but the theory of why there would be an effect also indicates it would be a minor affect. I'm not aware of any experimental data that demonstrates an actual effect. Are you aware of any?

Brew on

I can only site my own experience in 3 or 4 instances where I forgot to raise my mash to 168 degrees :smackrior to fly sparging. In those cases my sparge water was at the correct temperature, but the mash was still at 152 degrees.

In each of those instances, my efficiency dropped considerably as indicated by my SG being several point lower going into the kettle.

I can only attribute this to leaving some sugars behind in the mash due to the lower temperature of the mash at the start of the run off.

When I raise my mash temp to 168 before the run off, my numbers always go back up where they normally should be. Don't know what else to tell you.
YMMV

 

[jcav]

Hi Mike, I follow the same method as the Electric Brewery also. Just thought I'd mention to check your gap setting on your mill as it might have changed. I use the recommended 0.045 inch or (1.14 mm) gap setting which is about the width of a credit card. Also do not be afraid to keep an inch or two of water on top of the grain bed when sparging. You will get a little bit of a whirlpool in the beginning and then as you use up your sparge water the level will go down eventually.

I tend to keep water on top of the grain bed as long as I can when sparging as I do not have any channeling. I adjust the pump going into my boil kettle at a rate that it takes me between 55 minutes to an hour to collect my boil volume which is about 13.24 gallons for my system. I average 85% total brewhouse efficiency and mash efficiency in the 90's.

I read somewhere that if you have a good false bottom and no channeling that in theory you could put all of your sparge water on top of your grain bed, or even an infinite amount if your vessel could hold it, as you start to sparge, and it would not make a difference. The water on top squeezes the water through the grain bed like a piston under force as it goes through, into the pump and on into the boil kettle. Hope you get it figured out....

Edit: Oh yea I also always mash out!
John

 

[doug293cz]

I can only site my own experience in 3 or 4 instances where I forgot to raise my mash to 168 degrees :smackrior to fly sparging. In those cases my sparge water was at the correct temperature, but the mash was still at 152 degrees.

In each of those instances, my efficiency dropped considerably as indicated by my SG being several point lower going into the kettle.

I can only attribute this to leaving some sugars behind in the mash due to the lower temperature of the mash at the start of the run off.

When I raise my mash temp to 168 before the run off, my numbers always go back up where they normally should be. Don't know what else to tell you.
YMMV

A lot of brewers report the same behavior. The explanation is simple. Your conversion was incomplete at the end of your allotted mash time. The mash out gave additional time, and a rate boost due to the higher temp, for more conversion to occur, thus increasing conversion efficiency. The mash out cannot affect conversion efficiency if you have already converted 100% of the convertible starch. I have never seen any plausible mechanism for a mash out improving lauter efficiency, nor can I think of any. If you can explain why mash out could increase lauter efficiency, I would love to hear about it.

Brew on

 

[processhead]

A lot of brewers report the same behavior. The explanation is simple. Your conversion was incomplete at the end of your allotted mash time. The mash out gave additional time, and a rate boost due to the higher temp, for more conversion to occur, thus increasing conversion efficiency. The mash out cannot affect conversion efficiency if you have already converted 100% of the convertible starch. I have never seen any plausible mechanism for a mash out improving lauter efficiency, nor can I think of any. If you can explain why mash out could increase lauter efficiency, I would love to hear about it.

Brew on

The explanation I have heard most frequently works for me and is consistent with the physical effect of temperature on most fluids, sols and solvents.

Sugars in the mash become more soluble at higher temperatures with a resulting increase in extraction efficiency.

As simple example, compare how difficult it is to dissolve a spoonful of DME in a glass of room temperature water vs. a glass of hot water.

Granted, we are not talking about the same temperature extremes in a mash tun, but the same principle applies.

At higher temperatures, the liquid part of the mash also become less viscous allowing more efficient flow of sparge water through the mash at run off.
As an extreme example, compare the effect of heat on a container of LME at room temperature and at 180 degrees F.

To the OP, please accept my apologies for topic drift.

 

[doug293cz]

The explanation I have heard most frequently works for me and is consistent with the physical effect of temperature on most fluids, sols and solvents.

Sugars in the mash become more soluble at higher temperatures with a resulting increase in extraction efficiency.

As simple example, compare how difficult it is to dissolve a spoonful of DME in a glass of room temperature water vs. a glass of hot water.

Granted, we are not talking about the same temperature extremes in a mash tun, but the same principle applies.

At higher temperatures, the liquid part of the mash also become less viscous allowing more efficient flow of sparge water through the mash at run off.
As an extreme example, compare the effect of heat on a container of LME at room temperature and at 180 degrees F.

To the OP, please accept my apologies for topic drift.

There is never any sugar in the mash that needs dissolving. The sugar is in solution when it is created. Solubility of maltose at mash temps is 67% by weight (i.e. two lbs of maltose will dissolve in one lb of water.) This equivalent to an SG north of 1.300. You can't get anywhere near the solubility limit in a mash, so none of the sugar created in solution can precipitate out.

The viscosity of wort only drops about 16% going from mash temp to mash out temp (ref.) This would increase the rate at which you could drain the mash for a batch sparge, but for a fly sparge, you purposely slow the run off rate below the max possible to limit channeling. Then, as the sparge water works its way thru the grain bed the viscosity decreases much more than the initial viscosity decrease due to increased temp. Thus what remains in the grain bed has nothing to do with the viscosity of the original wort, as the original wort has been replaced by highly diluted wort. And, efficiency is determined by what remains in the grain bed.

Brew on

 

[cod3ck]

Pulling the noob card here --
What is the advantage to doing a fly sparge on homebrew size batches?

Doesn't throwing a buck or two more grain with a batch sparge spare the time and headache?

 

[doug293cz]

Pulling the noob card here --
What is the advantage to doing a fly sparge on homebrew size batches?

Doesn't throwing a buck or two more grain with a batch sparge spare the time and headache?

Theoretically, a fly sparge is more efficient than a single batch sparge, but only by about 5 percentage points on lauter efficiency. However, a poorly conducted fly sparge can easily have much lower efficiency than a batch sparge. It's much simpler to insure that a batch sparge is correctly done than a fly sparge, as there is no concern about channeling with batch sparging. With a double batch sparge you should be able to get within about 2 percentage points of a good fly sparge. Also, if you use a coarser crush to prevent stuck sparges when fly sparging, you could end up with lower conversion efficiency, thus losing the advantage you gained with lauter efficiency.

When it comes down to homebrewing, it's all about the preference of the individual brewer. You weigh the pros and cons of each process, and then make a choice based on your own criteria of what is best. There is no wrong choice.

Brew on

 

[processhead]

There is never any sugar in the mash that needs dissolving. The sugar is in solution when it is created. Solubility of maltose at mash temps is 67% by weight (i.e. two lbs of maltose will dissolve in one lb of water.) This equivalent to an SG north of 1.300. You can't get anywhere near the solubility limit in a mash, so none of the sugar created in solution can precipitate out.

The viscosity of wort only drops about 16% going from mash temp to mash out temp (ref.) This would increase the rate at which you could drain the mash for a batch sparge, but for a fly sparge, you purposely slow the run off rate below the max possible to limit channeling. Then, as the sparge water works its way thru the grain bed the viscosity decreases much more than the initial viscosity decrease due to increased temp. Thus what remains in the grain bed has nothing to do with the viscosity of the original wort, as the original wort has been replaced by highly diluted wort. And, efficiency is determined by what remains in the grain bed.

Brew on

I agree with your statement about the sugars already being in solution. My statement about solid DME sugars being more soluble in warmer water really doesn't apply in this case.

Where I believe a higher mashout temperature does improves sparge efficiency is its effectiveness in rinsing of the dissolved sugars that are absorbed by the grain bed at the end of the mash.

During the sparge, the sugar/solution absorbed in the grain bed will be more easily diluted and rinsed from a 170 degree mash than they will from a 152 degree mash, all other things being equal, i.e. sparge water temperature and equivalent volume.

Consider the amount of time and effort it take to completely rinse out a rag soaked in cold beer wort vs warm beer wort using hot water. Again, the example is extreme, but I believe the same principles apply.

This is the only way I can explain my empirical evidence during my mashing experience.

 

[LarMoeCur]

Thanks for the comments!
Some additional info:
- I dont do a mash out but the mash time will rise till I hit sparge temp in the HLT
- I dont use a sparge arm
- I sparge with 168F water but that will drop a little over time
- I've used a few thermometers to be sure about the temperatures
- The Barley Crusher 0.039 gap
It's basically the same process as The Electric Brewery uses.

That's what I'm gonna do:

- get a refractometer and measure multiple times during the whole process
- try one batch using batch sparging to see if the issue is not related to the fly sparging

I don't think that the recirculation is compacting the grain bed. I'm getting a good flow and the wort runs clear after 10 minutes or so.

For sure get a refractometer or just use your hydrometer and take more readings.

I think you should run another batch and do a mash out. A quick internet search of "will a mash out effect efficiency" yielded 100 post of the exact same problems you describe. Almost all of them showed gains in efficiency by doing a mash out. Sparging with 170F water does not raise the temperature of the grain bed.

Arguments about what the mash out is really doing is moot. All you should care about is "does it raise my efficiency?". I don't think anyone can argue that preforming a mash out when fly sparging adds to your efficiency numbers.

I'm also not a fan of the single hose laying on the grain bed. I know a lot of brewers do it and have great results. But to me you're asking for channeling. Your rinsing the grain bed not hosing it down. Think of washing your car or watering plants. A single stream of water goes to one spot. If that hose moves to the edge of the grain bed that water is running right down the side and rinsing nothing. Now if you have a good inch or two of sparge water above the grain bed and the hose floats you maybe ok.

Not knowing your exact processes and setup make it difficult to pin point it exactly. I'd start with a mash out. The mash out is the only way to brew constantly. Brewing is about controlling the variables. Not stopping the enzymatic process at the same point each brew day leaves a lot of variables that you may not be able to replicate again.

 

[MikeSkril]

I'm also not a fan of the single hose laying on the grain bed. I know a lot of brewers do it and have great results. But to me you're asking for channeling. Your rinsing the grain bed not hosing it down. Think of washing your car or watering plants. A single stream of water goes to one spot. If that hose moves to the edge of the grain bed that water is running right down the side and rinsing nothing. Now if you have a good inch or two of sparge water above the grain bed and the hose floats you maybe ok.

Yeah, I really think that my problem comes form channeling during the sparge. I have a 3-4 inches of water on the grain bed and the hose is floating on the outside of the kettle. The sparge water flows in slowly, not moving the top water much, I will try to find another way to sparge more evenly.

On the other hand, the hose method seems to be working fine for The Electric Brewery:

 

[LarMoeCur]

In that video to me it looks like the hose is along the edge of the bed. I know Kal has posted his numbers and gets great efficiency. It could be your false bottom or where you drain from or you're draining rate. I'd still do a mash out and maybe try a different way to deliver the sparge water.

 

[MikeSkril]

In that video to me it looks like the hose is along the edge of the bed. I know Kal has posted his numbers and gets great efficiency. It could be your false bottom or where you drain from or you're draining rate. I'd still do a mash out and maybe try a different way to deliver the sparge water.

Yeah, I'll do some tests when I find the time to brew.

I don't think that the false bottom is the issue. I had 80% efficiency with this mash tun when batch sparging, no mash out.

In my fly sparge, I drain 8 gal in 45 minutes, that is the same rate as Kal uses.

 

[MikeSkril]

I fixed the issue!

- I tightened the mill a little
- I did a mash out
- I've used a sparge ring instead of a hose on the grain bed

82% mash efficiency! I'm happy with that.

 

[processhead]

I fixed the issue!

- I tightened the mill a little
- I did a mash out
- I've used a sparge ring instead of a hose on the grain bed

82% mash efficiency! I'm happy with that.

That's Great!
Now tell us, which of the three fixed it?

 

[cod3ck]

That's Great!

Now tell us, which of the three fixed it?

+1

....sparge ring?!

 

[itsnotrequired]

I fixed the issue!

- I tightened the mill a little
- I did a mash out
- I've used a sparge ring instead of a hose on the grain bed

82% mash efficiency! I'm happy with that.

sounds like you have it figured out but i was going to add your sparge time seems short. sparging duration is time-dependent, not rate dependent. i believe most sparge times are on the order of 60-90 minutes, regardless of batch size. most of mine are on the order of 75 minutes and i get good efficiency.

think of a large macro-brewer making a 1000 gallon batch. at the rates you mentioned, they would spend days sparging

 

[augiedoggy]

was going to ask if it was possible your grain might be old or poor but I see you got it sorted out now.

 

[MikeSkril]

That's Great!
Now tell us, which of the three fixed it?

Good question. I don't have time to brew a lot, so did not change only one thing at a time to figure out what the issue was. Maybe it was a mix of all of the points I've changed.

I got my self a refractometer, and measured the mash every 15 minutes. That helped me to understand if the mash is going well.

After calculating, my brew-house efficiency is 75% and mash efficiency is 82%.