Efficiency issues with 2 vessel rims system

[Jaeger]

my efficiency has gone south and I'm hoping that some of you can help me figure out what I can do to fix it.

Background info:
I decided to upgrade from propane to electric 2 vessel rims system. I've found that the recirculation flows better when I have a bag in the mash tun, along with the false bottom. During the first few brews my efficiency was somewhere around 70%, with some being a touch higher and some a bit lower. The first problem I had was poor readings between preboil gravity and OG, with them being nearly the same. When I got some extra cash, I bought the Smartref from Anton Paar, which is much more accurate than my $20 refractometer. since then, my efficiency had dropped a bit, but nothing too concerning. I am, after all, brewing for me and not commercially. What's a few tenths of an ABV difference?

Well, last night I brewed up an Irish Red and boy was it not what I had expected. 52% efficiency. So, I'm trying to figure out where I can improve things.

Grain bill:
8 lbs Ashburn Mild malt
1 lb flaked corn
1 lb English medium crystal
2.2 oz roasted barley at the last 10 minutes of the mash for color only

all grain came from Northern Brewer, pre-milled as I don't have one yet.

expected Preboil Gravity was 1.040
expected OG was 1.048

My preboil gravity was 1.030
My OG was 1.039

Mashed for 10 minutes at 130, followed by 1 hour at 150, stirring the mash about every 15 minutes to prevent channeling

Mash PH was 5.35

-----

I know one of the big things I can do to help myself would be to buy a mill and mill my own grain. it's on my list and is the next brewery purchase.

could it be that having both a false bottom, which I think lets too much of the grain bits thru, and using a mesh bag be hurting more than helping? I think this could be something I might just have to get over and either deal with or get a new false bottom or upgrade the mash tun to something a bit better. it is just a standard morebeer 10 gallon cooler mash tun that wasn't necessarily designed for this.

Maybe I just need to mash for a longer period of time?

Any suggestions would be greatly appreciated.

 

[quantumguy]

I'm really guessing it's the crush of your grains. Can you post a pic of what it looks like?

 

[Jaeger]

I'm really guessing it's the crush of your grains. Can you post a pic of what it looks like?

Here is the system, the darker picture is the current setup, the brighter one is during the upgrade but shows the flow a bit better.

 

[quantumguy]

I don't suppose you have any crushed grains from this batch leftover that you could show? Also, do you do any lautering of your mash and did this change when you went from propane to electric?

 

[Jaeger]

I don't suppose you have any crushed grains from this batch leftover that you could show? Also, do you do any lautering of your mash and did this change when you went from propane to electric?

I don't at the moment, I'm at work, but indo have some roasted barley left over that I'll grab a picture of when I get home.

No laundering outside of the recirculation during the mash. I don't save separate water for sparging, tho I guess that would be something to try.

Originally I was gonna do a 3 vessel herms system but I don't have enough space. Someday I will tho

 

[doug293cz]

Maybe I just need to mash for a longer period of time?

Good chance this is correct.

Have you been buying pre-crushed grain from NB consistently, or have previous higher efficiency batches come from different vendors? A coarser crush will require more time to reach 100% conversion, all else being equal.

Have you used the Ashburn Mild malt previously? Different varieties, origins, and vintages of malts can have starch that varies in gelatinization temperature. Starches that start gelatinizing at higher temperatures will take longer to reach 100% conversion, all else being equal.

Brew on

 

[Jaeger]

Good chance this is correct.

Have you been buying pre-crushed grain from NB consistently, or have previous higher efficiency batches come from different vendors? A coarser crush will require more time to reach 100% conversion, all else being equal.

Have you used the Ashburn Mild malt previously? Different varieties, origins, and vintages of malts can have starch that varies in gelatinization temperature. Starches that start gelatinizing at higher temperatures will take longer to reach 100% conversion, all else being equal.

Brew on

No, typically I get my grain from morebeer and mill it there on their machine. Also my first time using Ashburn mild. Morebeer says they carry it but it was only available in a 55 lb sack, which I don't want since I don't have a mill yet.

Guess I'll be extending mash times as a start

 

[doug293cz]

I don't suppose you have any crushed grains from this batch leftover that you could show? Also, do you do any lautering of your mash and did this change when you went from propane to electric?

Lautering is separating the wort from the spent grains. All mashes are lautered. Sparging is rinsing the spent grains with fresh water in order to rinse additional sugar from the grain, either after first draining the initial wort from the grain (batch or dunk sparging), or simultaneously with draining the initial wort from the grain (continuous or fly sparging.)

I don't at the moment, I'm at work, but indo have some roasted barley left over that I'll grab a picture of when I get home.

No laundering outside of the recirculation during the mash. I don't save separate water for sparging, tho I guess that would be something to try.

Originally I was gonna do a 3 vessel herms system but I don't have enough space. Someday I will tho

Have you always done no-sparge brewing, or is that a recent change to your process?

Brew on

 

[quantumguy]

Lautering is separating the wort from the spent grains. All mashes are lautered. Sparging is rinsing the spent grains with fresh water in order to rinse additional sugar from the grain, either after first draining the initial wort from the grain (batch or dunk sparging), or simultaneously with draining the initial wort from the grain (continuous or fly sparging.)



Have you always done no-sparge brewing, or is that a recent change to your process?

Brew on

Ha, of course, I meant to ask if the OP was sparging. Getting late here.

 

[quantumguy]

Also, what is your recirculation rate? Perhaps you're getting some channeling in your mash?

 

[Jaeger]

Lautering is separating the wort from the spent grains. All mashes are lautered. Sparging is rinsing the spent grains with fresh water in order to rinse additional sugar from the grain, either after first draining the initial wort from the grain (batch or dunk sparging), or simultaneously with draining the initial wort from the grain (continuous or fly sparging.)



Have you always done no-sparge brewing, or is that a recent change to your process?

Brew on

I've almost always done no sparge with a rare exception of batch sparging.

 

[Jaeger]

Also, what is your recirculation rate? Perhaps you're getting some channeling in your mash?

I couldn't tell you an actual flow rate, but each ball valve on the discharge of the pump is usually open about 1/3 open and if I need to adjust the flow rate I adjust it slightly on the discharge out of the mash tun.

I've worried about channeling and about every 15 minutes or so I lift the lid and give things a good stir, just in case. I know that won't stop all channeling, but it helps with the big stuff and makes me feel better

 

[doug293cz]

All of this discussion so far is really just speculation since we are missing the critical measurements needed for diagnosing mash issues. The data that should be collected are:

• Total grain bill weight
• Weighted average extract potential for the grain bill
• Weighted average moisture content of the grain bill (this is the least critical of the data points, but useful)
• Strike water volume
• Sparge process
• Sparge water volume (if batch sparging)
• Times and temps of all mash rests, including transition times between steps
• End of mash wort SG, after complete wort homogenization, and prior to adding any sparge water
• Pre-boil volume and SG
• Post-boil volume and SG (OG)

With the above data it is possible to separate mash efficiency into its two factors - conversion efficiency and lauter efficiency (mash efficiency = conversion efficiency * lauter efficiency). This allows you to determine if your low efficiency is due to incomplete conversion of starch to sugar, or due to poor lautering process. You need to know which, as the fixes are different for each.

Accurate measurements are critical as the calculated results can be no more accurate than the measurements used in the calculations. i.e. if your volume measurements are +/- 10%, then your calculated efficiency values will be at least +/- 10%, and probably worse.

Brew on

 

[doug293cz]

I couldn't tell you an actual flow rate, but each ball valve on the discharge of the pump is usually open about 1/3 open and if I need to adjust the flow rate I adjust it slightly on the discharge out of the mash tun.

You should never throttle the input to a centrifugal pump, as this can lead to cavitation which can damage the pump over time. You should only throttle flow on the exit side of the pump.

Brew on

 

[day_trippr]

Do you keep your recirculation pump running while you're stirring? I wouldn't - but I wouldn't be disturbing a grain bed, either, except as a last resort if it starts getting locked up.

If there's a point in recirculation it's "to improve the efficiency of starch conversion by ensuring even contact between the enzymes and grains, resulting in a clearer wort, better extraction of sugars, and a higher yield of fermentable sugars; essentially leading to a higher quality beer with better clarity and flavor consistency." Stirring while recirculating will at the least cloud the wort as all the crap that gets caught up in the grain bed gets released.

Aaanyway when outcomes aren't what was planned the place to start is with "what was different from the time everything worked". In our case, one huge variable wrt efficiency is the crush - and if you're not doing the crushing - presumably with your mill set your way - you're at the mercy of whomever was doing the crushing, and minions do screw up...

Cheers!

 

[Jaeger]

You should never throttle the input to a centrifugal pump, as this can lead to cavitation which can damage the pump over time. You should only throttle flow on the exit side of the pump.

Brew on

I know, I meant I throttle the outlet of the pump coming out of the mash tun. I try and get the water flow to spray as evenly as possible over the grain bed so I don't want to mess with that flow, I simply hold more in the mash tun or let more out so as to keep the element covered.

All of this discussion so far is really just speculation since we are missing the critical measurements needed for diagnosing mash issues. The data that should be collected are:

• Total grain bill weight
• Weighted average extract potential for the grain bill
• Weighted average moisture content of the grain bill (this is the least critical of the data points, but useful)
• Strike water volume
• Sparge process
• Sparge water volume (if batch sparging)
• Times and temps of all mash rests, including transition times between steps
• End of mash wort SG, after complete wort homogenization, and prior to adding any sparge water
• Pre-boil volume and SG
• Post-boil volume and SG (OG)

With the above data it is possible to separate mash efficiency into its two factors - conversion efficiency and lauter efficiency (mash efficiency = conversion efficiency * lauter efficiency). This allows you to determine if your low efficiency is due to incomplete conversion of starch to sugar, or due to poor lautering process. You need to know which, as the fixes are different for each.

Accurate measurements are critical as the calculated results can be no more accurate than the measurements used in the calculations. i.e. if your volume measurements are +/- 10%, then your calculated efficiency values will be at least +/- 10%, and probably worse.

Brew on

I'll be able to get some of these numbers tomorrow from beersmith. I do know some off the top of my head tho.

Grain weight is 10lbs, 2.2oz

Strike water volume was 8.5 gallons

Mash temps and times:
10 minutes at 130f
5 minutes to raise to and stabilize at 150
60 minutes at 150
5 minutes to raise to and stabilize at 170
10 minutes at 170 for washout

Post mash SG 1.030. No sparge process

Preboil volume and SG -7.75 gallons, 1.030
Post boil volume and SG - 6.25 gallons, 1.039

Not sure where I would find the weighted average extract potential tho. Wouldn't that have to do with the grain lots?

 

[Climb]

How about using your Smartref from Anton Paar to monitor the gravity during the mash? When the readings are stable and hopefully close to the projected gravity, the mash is done.

Any remaining efficiency problem is with launtering and or (lack of) sparging.

 

[Zanatrik]

I would generally blame either the crush or the grains that you hadn't tried before. I have never sparged and while it might add efficiency, I have never had significant issues hitting numbers.

The other thing that has happened to me at least once is that my temp got off and while my target was 151 I was actually mashing closer to 159, so I lost some fermentable sugar. It may be worth checking with a second thermometer to confirm that maybe you weren't a bit low.

In any case, trial and error is good for the soul, itll make you a better brewer in the end. Journey before destination! (I like your icon)

 

[micraftbeer]

A lot of good feedback above, I thought I'd chime in with:

1. Grain crush is the unexpected jinx that shows up randomly to spoil a brew day until you start milling your own. Whether it's to blame here or not, of course we don't know.

2. I'm suspicious of your main malt being that Amber malt. First off, my experience with Amber is the tiniest amount brings on the most overpowering roast flavor. I'm talking I use it at the 0.5% of my grain bill in my 1.046OG/4% ABV British Bitters, and I can detect it. I like it as a coplement, but you blew my mind seeing it as your main base malt. I would treat it as a "flavoring malt" and dial that way back and use a Maris Otter or Briess Brewer's Malt. Aside from the flavor, it might not have as much diastatic power to get the job done. Hence your low efficiency, or maybe something once you start monitoring the gravity through mash with your Anton, takes 2 hours to convert or something.

3. I didn't see any comments to your question about false bottom + bag. I can't see this being an effect on efficiency. Maybe you don't need both, but if you're still able to get a recirculation flow without compacting the grain bed or getting a stuck mash, at most it just makes an extra thing you have to wash at the end of brew day.

 

[Jaeger]

How about using your Smartref from Anton Paar to monitor the gravity during the mash? When the readings are stable and hopefully close to the projected gravity, the mash is done.

This may be the most common sense thing I've read that now I'm kicking myself over. I guess we can get so wrapped up in a "standard process" that we forget to use common sense. Thank you!

I would generally blame either the crush or the grains that you hadn't tried before. I have never sparged and while it might add efficiency, I have never had significant issues hitting numbers.

The other thing that has happened to me at least once is that my temp got off and while my target was 151 I was actually mashing closer to 159, so I lost some fermentable sugar. It may be worth checking with a second thermometer to confirm that maybe you weren't a bit low.

In any case, trial and error is good for the soul, itll make you a better brewer in the end. Journey before destination! (I like your icon)

I've taken my digital meat thermometer to the boil kettle while Recirculating and the temp is only about 1 degree higher. I have the probe set on the inlet of the mash tun and will someday put an analog thermometer on the outlet

Thanks! I'm working my way thru wind and truth right now, tho I need to catch up on other books by sanderson as well to fully understand some of the background characters.

A lot of good feedback above, I thought I'd chime in with:

1. Grain crush is the unexpected jinx that shows up randomly to spoil a brew day until you start milling your own. Whether it's to blame here or not, of course we don't know.

2. I'm suspicious of your main malt being that Amber malt. First off, my experience with Amber is the tiniest amount brings on the most overpowering roast flavor. I'm talking I use it at the 0.5% of my grain bill in my 1.046OG/4% ABV British Bitters, and I can detect it. I like it as a coplement, but you blew my mind seeing it as your main base malt. I would treat it as a "flavoring malt" and dial that way back and use a Maris Otter or Briess Brewer's Malt. Aside from the flavor, it might not have as much diastatic power to get the job done. Hence your low efficiency, or maybe something once you start monitoring the gravity through mash with your Anton, takes 2 hours to convert or something.

3. I didn't see any comments to your question about false bottom + bag. I can't see this being an effect on efficiency. Maybe you don't need both, but if you're still able to get a recirculation flow without compacting the grain bed or getting a stuck mash, at most it just makes an extra thing you have to wash at the end of brew day.

The base malt isn't amber malt, it's a pale malt by breiss designed as a base for styles like mild.

I mostly use the bag inside to keep the smaller grain particles from moving thru the system, but it has the added effect of elevating the grain bed off the false bottom just enough to keep it from getting sucked down and sticking the mash. I tie it off to some eye hooks to hold it in place, then after brew day I flip it inside out, rinse it and hang it to dry. Once dry I shake it out a bit and any remaining particles fly off. Then I boil it for a few minutes to make sure anything that hasn't come out will be completely denatured and won't carry anything over to the next batch

 

[stevehaun]

Crush

 

[JohnDBrewer]

You got a new system so your going to have to play with your numbers until you dial it in for a while. Looks like you have alot of nice equipment but the grain mill is essential. I know throwing money at a problem is the answer of last resort. With RIMS you want to crush it fat. I stir the mash once all the water is added, then again after about 10-15 minutes of letting the mash hydrate before turning on the pump. I don't stir again and let the recirculation work. I've tried several different ways, several different times and combination - finer crush, using a bag (with my false bottom) and stirring my mash occasionally and/or frequently. All lowered my efficiency. I believe a finer crush and stirring creates channeling or compacts the bed, all bad for RIMS. Not sure about a bag, maybe channeling down the outside of the bag? Anyway, that's my experience. It's frustrating and disappointing when you get a new system and you don't hit your numbers. Keep some DME on hand to adjust your numbers up in the short term. Keep at it and let us know.

 

[doug293cz]

Grain weight is 10lbs, 2.2oz

Strike water volume was 8.5 gallons

Mash temps and times:
10 minutes at 130f
5 minutes to raise to and stabilize at 150
60 minutes at 150
5 minutes to raise to and stabilize at 170
10 minutes at 170 for washout

Post mash SG 1.030. No sparge process

Preboil volume and SG -7.75 gallons, 1.030
Post boil volume and SG - 6.25 gallons, 1.039

Not sure where I would find the weighted average extract potential tho. Wouldn't that have to do with the grain lots?

I searched for Ashburne Mild malt and found these two references:

https://www.brewingwithbriess.com/blog/malt-of-the-month-ashburne-mild/​

https://www.brewingwithbriess.com/products/base-malts/#Ashburne​

According to these, the malt has a DP of 65, and at 80% of the mash, the weighted DP for all grains is 65 * 0.8 = 52. This should be enough to fully convert the starches, but you don't have much margin (min DP for full conversion is around 40 IIRC.) Moisture is 4%.

The potential for this malt is given as 81% (assume dry basis, fine grind), which equates to 46.2 * 0.81 = 37.4 pts/lb. Other potentials are (from BeerSmith):

Flaked corn: 37 pts/lb​

Medium Crystal: 34 pts/lb​

Roasted Barley: 25 pts/lb​

So the weighted potential is: (8 * 37.4 + 37 + 34 + 0.1375 * 25) / 10.1375 = 36.9

Using your volumes, the above info, and my mash and lauter simulation spreadsheet, I get your expected pre-boil SG as 1.039 @ 100% conversion efficiency, and post-boil SG (OG) as 1.049. Your pre-boil SG of 1.030 works out to a conversion efficiency of 74.6%, which basically sucks. I get your projected OG as 1.037 vs. your measured 1.039. The fact that these last two numbers are not the same indicates that you have errors in one of more of: pre-boil SG, OG, pre-boil volume, and/or post-boil volume. Pre-boil pts/gal * pre-boil volume must equal post-boil pts/gal * post-boil volume if all measurements are correct.

Your lauter efficiency comes in at 86.6%, which is pretty good for no-sparge. This good result is due to your low grain absorption rate of 0.074 gal/lb.

Your mash efficiency came in at 64.3%. Brewhouse efficiency will come in lower than that if you left anything behind in the BK when transferring to the fermenter.

Your very low conversion efficiency is primarily due to having too short a mash time for the crush coarseness that you had. Your relatively low mash DP may have also contributed. I completely support @micraftbeer 's suggestion to monitor your mash SG to determine when your mash is fully converted. I suggest start taking SG measurements at 45 minutes into the mash, and every 15 minutes thereafter, until your SG stops increasing from one measurement to the next.

Brew on

 

[Jaeger]

Thanks for all the help with this post mortem. I really appreciate it. Some of this, like needing my own mill, I've known, I just haven't done yet and I'm still kicking myself for not just continuing the mash when I saw the preboil gravity was low.

I guess these things help make us better brewers in the end. Live and learn.

Again, many thanks to all!