Author Topic: Mash/Brewhouse Efficiency  (Read 622 times)

Offline Kirk

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Mash/Brewhouse Efficiency
« on: December 31, 2017, 03:58:19 PM »
A few questions regarding Mash/brewhouse efficiency.

My efficiency always seems to be quite low... ~ 60%. I have a electric HERMS system which constantly cycles the mash through my heat exchanger. The temp probe which monitors the mash temp is connected via a Tee in the mash tun output ball valve. I feel this is the best way to get an overall mash temp reading, as the mash liquid is thourally mixed, as opposed to measuring it inside the tun, where pockets of different temperatures will be found.

I typically doe in and mix the grist well until I hit my target mash temp, then start slowly recirculating the mash through the heat exchanger. I don't typically stir the mash a lot, but this time I did more than usual. I let the mash go 60 mins, then ramp up to around 158 as I was heating the Sparge water. One thing that I think could be hurting my efficiency is the sparge arm and plastic distributor. In order to get a better mash temp control, the flow rate of the grist is set quite slow, which doesn't allow the wort coming back into the mash tun to "hit" the entire surface of the grain bed. I've often thought this could be a source of my poor efficiency. I've thought about designing more of a circular device with lots of holes to spread out the wort/sparge water coming back to the tun, to help even out contact with the grain bed. I have the same problem during sparging.

Sparge - I heated the sparge water to around 167 or so then proceeded in fly sparging until I hit my boil volume of 7.75 gallons.

I've tried both draining some of the first runnings before starting the fly sparge, and starting the fly sparge at the start. Neither appears to be making any significant increases in my overall efficiency.
Mash temps are those typical to produce good fermentability and body (152-154F).

I try to maintain ~ 1 to 2 inches of water above the grain bed during the sparge as well.

Thoughts?? I'd like to hear how others are setting up and conducting their mash/sparges.

I've also gotten grain crushed from 2 different mils.


Online BrewBama

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Re: Mash/Brewhouse Efficiency
« Reply #1 on: December 31, 2017, 05:01:23 PM »
If you’re not hitting your OG or FG and/or volumes, check not only crush but accurate brewing liquor measurement.

Brewhouse efficiency is a result of accumulated losses from A to Z. Leaving wort in the mash tun, in the kettle, or in the fermenter all add up. Accurate measurement of strike and sparge liquor, wort run off both in the kettle pre boil, boil off, and into the fermenter post boil.


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Offline mabrungard

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Re: Mash/Brewhouse Efficiency
« Reply #2 on: December 31, 2017, 07:05:29 PM »
The temp probe which monitors the mash temp is connected via a Tee in the mash tun output ball valve. I feel this is the best way to get an overall mash temp reading, as the mash liquid is thourally mixed, as opposed to measuring it inside the tun, where pockets of different temperatures will be found.

NOPE!!!!!

This is exactly the wrong place to measure wort temperature. Wort temperature MUST be measured immediately downstream of your heat source or you will overheat your wort. The temperature of your exiting wort doesn't matter AT ALL. That exiting wort temperature will eventually reach your targeted mashing temperature, but you can't drive your heating system's response with the exit temperature reading.

If you haven't been monitoring your wort temp right after the heater, you have probably missed learning that the wort temp has been way too high and all of your enzymes may have been denatured.

Don't worry about your wort distributor as long as you have liquid depth over the bed. You could use anything and it will work equally well. A hose sitting on top of your bed is fine too and it will help reduce oxidizing your wort. By the way, a sprinkler setup increases your heat losses, so its far from ideal in a RIMS or HERMS.

My experience is that the main things affecting efficiency are crush and the duration of runoff. A finer crush improves efficiency, but you have to balance that with the ability to get flow through the bed. The runoff duration should be at least 15 minutes and pushing that much longer does improve extraction efficiency.
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Offline Robert

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Re: Mash/Brewhouse Efficiency
« Reply #3 on: December 31, 2017, 07:11:05 PM »
Do you mean your efficiency is ~60% or your yield? (I notice some confusion on these terms sometimes.)  Yield is ratio how many lbs. of extract you get from how many lbs. of grain.  Efficiency is ratio of how much extract you get to how much you could expect under ideal conditions. If your YIELD is ~60%, that's still ~80% efficiency, which is not great but within the realm of what some homebrew system give, so you are probably just looking at tweaking your system, being more careful, accurate, and so on, and maybe tweaking your setup and procedures a bit.  If your actual efficiency  is in the 60% range, you may need to really reexamine your whole system.  Something's not right there. Or if you like your beer otherwise, you could just buy extra malt and leave everything alone!
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Offline denny

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Re: Mash/Brewhouse Efficiency
« Reply #4 on: December 31, 2017, 07:12:02 PM »
The runoff duration should be at least 15 minutes and pushing that much longer does improve extraction efficiency.

unless you batch sparge....
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Offline Kirk

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Re: Mash/Brewhouse Efficiency
« Reply #5 on: January 01, 2018, 03:02:51 PM »
The temp probe which monitors the mash temp is connected via a Tee in the mash tun output ball valve. I feel this is the best way to get an overall mash temp reading, as the mash liquid is thourally mixed, as opposed to measuring it inside the tun, where pockets of different temperatures will be found.

NOPE!!!!!

This is exactly the wrong place to measure wort temperature. Wort temperature MUST be measured immediately downstream of your heat source or you will overheat your wort. The temperature of your exiting wort doesn't matter AT ALL. That exiting wort temperature will eventually reach your targeted mashing temperature, but you can't drive your heating system's response with the exit temperature reading.

If you haven't been monitoring your wort temp right after the heater, you have probably missed learning that the wort temp has been way too high and all of your enzymes may have been denatured.

Don't worry about your wort distributor as long as you have liquid depth over the bed. You could use anything and it will work equally well. A hose sitting on top of your bed is fine too and it will help reduce oxidizing your wort. By the way, a sprinkler setup increases your heat losses, so its far from ideal in a RIMS or HERMS.

My experience is that the main things affecting efficiency are crush and the duration of runoff. A finer crush improves efficiency, but you have to balance that with the ability to get flow through the bed. The runoff duration should be at least 15 minutes and pushing that much longer does improve extraction efficiency.

Thanks for your reply.

A couple things. I have a counterflow heat exchanger design which has a PID controlling the HLT water temp. I typically set this for approximately 2-3 degrees higher than the mash water temp. The HLT water is pumped through the outer heat exchanger tube opposite the wort direction from the mash. The small temperature delta between the HLT controlled temp and the mash temp keeps my mash temp within about a degree of my set point. I can't see how the wort temp exiting the heat exchanger is any higher than the HLT set point. So in this particular case, the HLT was set to 155, and my mash was targeted at 153-154.  If anything it should cool slightly from the HLT output to the mash entry point, but my hoses are very short (1'). Also I keep the lid on the mash tun to help hold the heat at the set point.

My crush has been suspect for sure. I've bought my grain from 2 different home brew shops, but with basically the same results. I do feel that my runoff might be too quick, but I'd say it takes at least a 1/2 hour to get to 7.5 gallons or so.

It makes me sick when hear people saying they get 80% efficiency! :)

Offline Kirk

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Re: Mash/Brewhouse Efficiency
« Reply #6 on: January 01, 2018, 04:34:57 PM »
Do you mean your efficiency is ~60% or your yield? (I notice some confusion on these terms sometimes.)  Yield is ratio how many lbs. of extract you get from how many lbs. of grain.  Efficiency is ratio of how much extract you get to how much you could expect under ideal conditions. If your YIELD is ~60%, that's still ~80% efficiency, which is not great but within the realm of what some homebrew system give, so you are probably just looking at tweaking your system, being more careful, accurate, and so on, and maybe tweaking your setup and procedures a bit.  If your actual efficiency  is in the 60% range, you may need to really reexamine your whole system.  Something's not right there. Or if you like your beer otherwise, you could just buy extra malt and leave everything alone!

Yeah there is definitely some confusion with the terms. BeerSmith tells me my Mash efficiency, which I take to be YIELD, is ~ 69-70%. My pre-boil numbers were 1.039 @ 7.75 gallons (12lbs of grain). My system boils off at ~ 2 gallons per hour, so I got ~ 5.75 gallons at the end of my boil. I lost a little going from the boil to the fermentor, but ended up with ~ 5.25 gallons at 1.052. BeerSmith tells me this is a Brewhouse efficiency of ~ 62%. So I guess my mash eff/yield could be a little better, but not terrible. I do push all the wort remaining in the heat exchanger / chiller coil out into the fermentor as well.


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Re: Mash/Brewhouse Efficiency
« Reply #7 on: January 01, 2018, 04:39:08 PM »
I have a kettle RIMS system (though the recirculation aspect of it is the only important part I suppose), and doing no-sparge I hit 72% consistently (at least that is the number I put in Beersmith which correctly predicts my output wort gravity).  I was having problems where I was down closer to 60, and here are some of my observations from my system. 

The crush was counter intuitive compared to batch sparging.  When I had the crush finer, I had to drop the recirculation rate which didn't help for temperature control or ramping speed.  When I widened out the gap on my mill, the crush was courser but the husks were more intact and the flow rate could be increased.  The net effect of it was that the increased flow/agitation resulted in an increase in efficiency. 

I also started doing multi step mashes (why else have a RIMS/HERMS system?), with steps at 146, 153, 161, and 170 (mashout).  This extended the total mash time to more like 1.5-2 hours.  Monitoring the gravity, you can see the gravity keep increasing at each step until it kind of flattens out.   For example, on my last batch at the end of the 153 step, the gravity was 1.038 but by the end of the 161 step it was 1.047 with a target of 1.048.  I don't know if it might help you to monitor the gravity when you are at your 158F step and see if it is still going up while recirculating and make sure you aren't cutting things off too early.

I would imagine if you are sparging you would certainly be able to get better than the 72% I'm getting with no-sparge.
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Offline Robert

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Re: Mash/Brewhouse Efficiency
« Reply #8 on: January 01, 2018, 04:50:07 PM »
A few questions regarding Mash/brewhouse efficiency.

My efficiency always seems to be quite low... ~ 60%. I have a electric HERMS system which constantly cycles the mash through my heat exchanger. The temp probe which monitors the mash temp is connected via a Tee in the mash tun output ball valve. I feel this is the best way to get an overall mash temp reading, as the mash liquid is thourally mixed, as opposed to measuring it inside the tun, where pockets of different temperatures will be found.

I typically doe in and mix the grist well until I hit my target mash temp, then start slowly recirculating the mash through the heat exchanger. I don't typically stir the mash a lot, but this time I did more than usual. I let the mash go 60 mins, then ramp up to around 158 as I was heating the Sparge water. One thing that I think could be hurting my efficiency is the sparge arm and plastic distributor. In order to get a better mash temp control, the flow rate of the grist is set quite slow, which doesn't allow the wort coming back into the mash tun to "hit" the entire surface of the grain bed. I've often thought this could be a source of my poor efficiency. I've thought about designing more of a circular device with lots of holes to spread out the wort/sparge water coming back to the tun, to help even out contact with the grain bed. I have the same problem during sparging.

Sparge - I heated the sparge water to around 167 or so then proceeded in fly sparging until I hit my boil volume of 7.75 gallons.

I've tried both draining some of the first runnings before starting the fly sparge, and starting the fly sparge at the start. Neither appears to be making any significant increases in my overall efficiency.
Mash temps are those typical to produce good fermentability and body (152-154F).

I try to maintain ~ 1 to 2 inches of water above the grain bed during the sparge as well.

Thoughts?? I'd like to hear how others are setting up and conducting their mash/sparges.

I've also gotten grain crushed from 2 different mils.
No, those numbers are your EFFICIENCY.  Your yield is, by those numbers, 54% pre-boil, 49% post-boil. (Discrepancy might just be not correcting volume for temperature? If the post numbers are accurate volume of chilled wort, that could be.)  Anyway, that's not good.  FWIW I just mash in my kettle, transfer to a cooler lauter tun, and I easily get 71-72% yield, which is >93% efficiency.  By other people's posts, sounds like automation is not being your friend. Hope they can help you adjust your system!

EDIT for spelling
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Online BrewBama

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Re: Mash/Brewhouse Efficiency
« Reply #9 on: January 01, 2018, 04:52:00 PM »
Maybe a JSP Malt Mill is in your future.


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Offline Robert

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Re: Mash/Brewhouse Efficiency
« Reply #10 on: January 01, 2018, 04:54:22 PM »
Maybe a JSP Malt Mill is in your future.


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Yeah, one of my best decisions ever!  Have the gap at .030" and have no problems with a quick runoff.
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Offline JT

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Re: Mash/Brewhouse Efficiency
« Reply #11 on: January 01, 2018, 05:02:51 PM »
I monitor mash temp in a couple of places.  One, in the tun (via Blichmann brewmometer).  The other is directly after exiting the RIMS Rocket.  I find that to keep the mash at a constant 150, I need to have RIMS Rocket set to 153.  If I want to increase mash temp when step mashing, I'll crank the controller up to generally 10 degrees or so beyond my target kettle temp.  This allows me to bump around degree per min.  I'm not sold that I'm denaturing all my enzymes in the brief period the wort flows past the heat, even though the RIMS controller might be set at 172 until I get 162 in the mash tun. 

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Offline Kirk

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Re: Mash/Brewhouse Efficiency
« Reply #12 on: January 02, 2018, 01:09:58 AM »
I monitor mash temp in a couple of places.  One, in the tun (via Blichmann brewmometer).  The other is directly after exiting the RIMS Rocket.  I find that to keep the mash at a constant 150, I need to have RIMS Rocket set to 153.  If I want to increase mash temp when step mashing, I'll crank the controller up to generally 10 degrees or so beyond my target kettle temp.  This allows me to bump around degree per min.  I'm not sold that I'm denaturing all my enzymes in the brief period the wort flows past the heat, even though the RIMS controller might be set at 172 until I get 162 in the mash tun. 

  "If more of us valued food and cheer and song above hoarded gold, it would be a merrier world."

I'm in a similar boat with my HERMS system. I need a small delta (2-3F) between the HLT temp and the mash temp to keep the mash temp consistent while the PID is in auto tune mode (varies the duty cycle) to control the overall temp of the HLT. To step mash, I take the PID out of auto tune and turn up the temp of the PID to a few degrees higher. Once the HLT temp is within 2 degrees, I turn auto tune back on, which creeps up to the setpoint.

I think I will start doing more step mashing, with a longer overall mash time, checking the gravity along the way to see if I can make more improvements. I decided to do a single mash temp to keep things more simple.

I appreciate everyone's insight