Terrible efficiency with new mash tun.

[ChzyMnky]

Honestly, I'm not quite sure which forum to put this post in... But for right now, I'm going to go with the "equipment" forum.

I brewed today for the first time with my new Spike 15gal mash tun. Super duper nice piece of equipement, but I only got ~41% mash efficiency. Beersmith was estimating 1.055 pre-boil gravity (@75%eff), but I only came in at 1.043. (It may not only be related to my mash tun setup, I'll explain futher down). Trying to figure out what I need to do in the future to improve, maybe you guys can give me some ideas?

Equipment:
15 gal Spike mash tun
PID controlled RIMs
(I had the RIMs recirculate through a silicone hose inside the tun, kinda resting on top of the mash. I also sparged through the same hose.)

Recipe: Belgian Wit
6 lbs White Wheat Malt (2.4 SRM) Grain 1 38.1 %
2 lbs Pilsner (2 Row) UK (1.0 SRM) Grain 2 12.7 %
2 lbs Wheat, Flaked (1.6 SRM) Grain 3 12.7 %
1 lbs Biscuit Malt (23.0 SRM) Grain 4 6.3 %
1 lbs Caramel/Crystal Malt - 10L (10.0 SRM) Grain 5 6.3 %
1 lbs Pale Malt (2 Row) Bel (3.0 SRM) Grain 6 6.3 %
12.0 oz Oats, Flaked (1.0 SRM)
~a couple handfuls of rice hulls
(About 14.25lbs of grain total)

Water Profile:
6gal distilled, used Bru'n Water to build my own Hoegaarden profile
Calcium (ppm) 51
Magnesium (ppm) 10
Sodium (ppm) 24
Sulfate (ppm) 85
Chloride (ppm) 57
Bicarbonate (ppm) 63
Calculated Mash pH 5.4

Mash Schedule:
Mash in @ 127deg F to hit target of 122deg F
Let mash settle for 10min
Recirc @ 122deg F for 20min
Step to 152deg F
152deg F for 60 min
Step to 168deg F
168deg F for 10 min
Sparge with 168deg water
Collect 7.9 gal in brew kettle

I mashed in and hit 122 exactly. After letting the mash settle for 10 min, I took a pH measurement. It was up around 6! Usually I'm pretty close after calculating with Bru'n Water, so I was pretty surprised... I added 6tsps of 10% phosphoric acid, and got the mash down to ~5.5ph.

I have two theories:
1) Due to the mash pH being way off at the beginning, I didn't get full convernsion.
2) Sparging with just a coiled hose on top of the mash caused me to not rinse enough sugars off the grain. However, my end runnings gravity was somewhere around 1.013...

What do you guys think? Now that I've re-read my post, I'm actually leaning towards the pH issue because my end runnings was pretty low...

Thanks in advance!
Eric

 

[SoCal-Doug]

Did you have an inch or two or wort on top of the grain bed during mash and sparge or was the grain bed exposed? My system works the same way and i'm typically in the high 80's with some recipes at 90.

You initial pH was high, but i don't thing it was high enough to bring you down to 40%

Did you hit your pre-boil volume?

How did you measure your preboil SG? refractometer? Was it calibrated? Hydrometer? Did you compensate for temp?

Have you proven/calibrated the temp sensor used by the rims controller?

Sorry, gotta ask the basics first

 

[SoCal-Doug]

Something isn't computing. I put your recipe into beersmith. For a 5.75 gallon batch (because you mentioned collecting 7.9 gal into the BK, sp i started there), i'm coming up with an OG of 1.065 at 75%eff. In my 15 gallon system (sure, our plumbing is different but just for discussion sake...) i would start with 6.3gal in the mash tun and plumbing (that's the water i do my mineral adjustments on, i sparge with straight RO), then sparge another 3.23 gallons, after absorption of roughly 1.65 gal, my BK would get about 7.88gal. boil off 1.6 in 60 mins, shrink 0.25, and put about 5.75 into the fermenter. Coming in at an preboil SG of 1.043 (nailing the volumes) would be a mash efficiency of 65.4%

When i calculate my mash liquor quanity, its 1.25 qt/lb for the grain (4.3 gal at 13.75lb grain), 0.588 gals for the lines, pump, and plumbing (mine is a HERMS, your plumbing will be different), and 1.5 gal above the grain bed (about an inch and a half in my size of kettle). This give the 6.3g starting point for the mash.

 

[ChzyMnky]

Did you have an inch or two or wort on top of the grain bed during mash and sparge or was the grain bed exposed? My system works the same way and i'm typically in the high 80's with some recipes at 90.

You initial pH was high, but i don't thing it was high enough to bring you down to 40%

Did you hit your pre-boil volume?

How did you measure your preboil SG? refractometer? Was it calibrated? Hydrometer? Did you compensate for temp?

Have you proven/calibrated the temp sensor used by the rims controller?

Sorry, gotta ask the basics first

Thanks for the reply!

During recirc I only had 1/4~1/2" of wort above the grain, because I didn't want to make my mash too thin. I had ~1" during sparging. Do you think that could have done it?

I measured the gravity with a refractometer. After the first low reading I checked the calibration with DI water, and it was dead-nuts on. I have a dial thermometer in my new mash tun, as well as the RTD probe at the outlet of my RIMs tube. There is a lag between the two when stepping temperatures, but once everything is stabilized they are right in line with each other.

 

[ChzyMnky]

Something isn't computing. I put your recipe into beersmith. For a 5.75 gallon batch (because you mentioned collecting 7.9 gal into the BK, sp i started there), i'm coming up with an OG of 1.065 at 75%eff. In my 15 gallon system (sure, our plumbing is different but just for discussion sake...) i would start with 6.3gal in the mash tun and plumbing (that's the water i do my mineral adjustments on, i sparge with straight RO), then sparge another 3.23 gallons, after absorption of roughly 1.65 gal, my BK would get about 7.88gal. boil off 1.6 in 60 mins, shrink 0.25, and put about 5.75 into the fermenter. Coming in at an preboil SG of 1.043 (nailing the volumes) would be a mash efficiency of 65.4%

When i calculate my mash liquor quanity, its 1.25 qt/lb for the grain (4.3 gal at 13.75lb grain), 0.588 gals for the lines, pump, and plumbing (mine is a HERMS, your plumbing will be different), and 1.5 gal above the grain bed (about an inch and a half in my size of kettle). This give the 6.3g starting point for the mash.

Unfortunately I'm at work, so I can't see my exact numbers in BeerSmith. I think I had it set for a 6 gal batch. My mash thickness was ~1.4, and between my RIMs and hoses I have about 0.75 gal of volume. I disconnect all of it and drain it into the kettle when I start to sparge. There is maybe 0.25 gal under my false bottom that doesn't make it into the kettle. I'll check everything when I get home and update if required.

Thanks again!

 

[ChzyMnky]

Doug,

Just got home and looked at BeerSmith. My memory was close, but not perfect.

Mash thickness: 1.45qt/lb
Mash Tun Addition: 0.71gal (RIMs, hoses, etc that get drained into the kettle)
Deadspace: 0.3 gal
Pre-boil calculated gravity: 1.055 (@ 75% brewhouse efficiency, 83.5% mash efficiency)
OG: 1.070 (@ 75% brewhouse efficiency, 83.5% mash efficiency)

So, 13.75lbs x 1.45 = 4.98gal, plus 1 gal of RIMs/hose/deadspace = 6 gal of water.

 

[SoCal-Doug]

That sounds closer to reality So... first problem IMO is such little volume on top of the grain bed. My hunch is you were channeling the flow which can really kill conversion efficiency. Get it up to a couple inches. Increase your "mash tun addition" by whatever amount is needed to give you at least an inch and a half (1.5" to 2" at whatever diameter the kettle is, calculated into gallons). Position your return tube so it lays on top of the grain bed and creates a continuous swirly liquid motion on top of the grain. Good examples can be found by searching youtube and google for "Brew Magic" sabco systems.

Don't worry about mash thickness in a recirculating system. That ratio comes from the old days of (and still applies to) static (non recirculating) mash tuns like igloo coolers. When you recirculate, you have a natural compaction of the mash because of gravity and wort flow. In theory, you can have 1 inch or 10 inches of wort over the grain and it will still compress nearly the same and "feel" the same ratio. The only reason i use the 1.25 number is because it has to be entered into beersmith in the mash (infusion) screen in order for it to calculate volumes. It is also a good/typical starting point for "zero water above the grain". Don't forget to calculate in the liquid quantity under your false bottom (if you have one in that setup, i'm not familiar with it). I'm guessing since you are using 1.45 for the ratio, that compensated for it.

All fluids in a recirculating mash system can be considered "recoverable" because when you sparge, you will "exchange" the wort with sparge water. There is technically no "deadspace" in the mash tun because at the end of sparge, any deadspace will be nearly clear and useless wort. Simply keep draining and sparging until your boil kettle reaches the preboil volume. At the end of the sparge, measure the pH ad SG of the draining liquid ("end runnings"). Good is < 1.010 and near 6.0 pH. Mine is typically 1.005 and 5.9. That will give you an idea of how well you rinsed the grains.

Sparging... Did you sparge SLOWLY? for 5 gallons, i would recommend a minimum of 30 to 40 minutes. Open the drain to the boil kettle and start dripping or trickling slowly. Valve in sparge water into your recirculating system at the same rate, so that the 2" of fluid is maintained. Your sparge water should be at 168 to 170 for the duration to keep the sugars nice and dissolved, and the slow sparge keeps everything rinsing thoroughly. A super fast sparge will drop efficiency.

And we might as well mention the grind. If you mill your grain at the local shop, someone may have jacked with the settings. Too big and it can have a definite effect on your efficiency. To small and your mash will turn to concrete and nothing will flow through it ("stuck mash" - pain in the a$$). I'm a 0.036" guy, others vary from .030 to 0.040. Run some rice hulls for cheap insurance if it makes you nervous. They are a wonderful thing. A half pound or so per 5 gallons of batch is a good starting point.

Another thing you can do is lightly stir the grain 1 to 3 times during the mash. If the system is working properly, it wort should re-clear itself in a few minutes. This can help assure that all the grain gets a chance at conversion. I also will do a light stir at the end of each mash step and as i'm ramping up to mashout temp. Can i prove it helps? nope. But it makes me feel better

Bet you a beer, your next batch is between 80% and 85% mash efficiency

 

[doug293cz]

Since mash efficiency is conversion efficiency times lauter efficiency, low mash efficiency can be due to:

1. Low conversion efficiency (not all starch converted to sugar)
2. Low lauter efficiency (usually due to channeling or sparging too fast)
3. A combination of 1 & 2

Obviously, in order to improve low mash efficiency, you need to know whether your situation is 1, 2 or 3.

Conversion efficiency can be calculated by measuring the SG of the wort in the MLT at the end of the mash, using the method here. If your conversion efficiency is less than 90 - 95% you need to work on that. It is possible to achieve 100% conversion efficiency. Finer crush can speed conversion, but needs to be balanced against the need to avoid a stuck sparge. Once you crush as fine as your system will tolerate, then increasing mash time can improve conversion efficiency. For your grain bill and 6 gal of strike water the effective mash thickness for efficiency calculation is 24 qts / 13.75 lb = 1.75 qt/lb. With 100% conversion efficiency, your end of mash wort SG should have been 1.071 - 1.072. Before measuring the end of mash SG, you need to insure that the wort is totally homogeneous. Best way to do this is stir the mash well and then recirc or vorlauf well.

Lauter efficiency is then calculated by dividing your mash efficiency by your conversion efficiency. A well conducted fly sparge should provide better lauter efficiency than a triple batch sparge (based on eff numbers I have seen from well run fly sparges.) For your grain bill, pre-boil volume, and strike volume, a triple batch sparge would have a lauter efficiency of about 88 - 89%, so a "good" fly sparge should be better than that.

One thing you might try is to do a single batch sparge process to see if you get better mash efficiency. If you do, that is an indication that your fly sparge process is lacking. When batch sparging you want to drain everything you can from the MLT and plumbing before you add your sparge water. Then add the sparge water, stir well, and recirc for a while to homogenize. Then run off the sparged wort.

Brew on

 

[ChzyMnky]

That sounds closer to reality So... first problem IMO is such little volume on top of the grain bed. My hunch is you were channeling the flow which can really kill conversion efficiency. Get it up to a couple inches. Increase your "mash tun addition" by whatever amount is needed to give you at least an inch and a half (1.5" to 2" at whatever diameter the kettle is, calculated into gallons). Position your return tube so it lays on top of the grain bed and creates a continuous swirly liquid motion on top of the grain. Good examples can be found by searching youtube and google for "Brew Magic" sabco systems.

Don't worry about mash thickness in a recirculating system. That ratio comes from the old days of (and still applies to) static (non recirculating) mash tuns like igloo coolers. When you recirculate, you have a natural compaction of the mash because of gravity and wort flow. In theory, you can have 1 inch or 10 inches of wort over the grain and it will still compress nearly the same and "feel" the same ratio. The only reason i use the 1.25 number is because it has to be entered into beersmith in the mash (infusion) screen in order for it to calculate volumes. It is also a good/typical starting point for "zero water above the grain". Don't forget to calculate in the liquid quantity under your false bottom (if you have one in that setup, i'm not familiar with it). I'm guessing since you are using 1.45 for the ratio, that compensated for it.

All fluids in a recirculating mash system can be considered "recoverable" because when you sparge, you will "exchange" the wort with sparge water. There is technically no "deadspace" in the mash tun because at the end of sparge, any deadspace will be nearly clear and useless wort. Simply keep draining and sparging until your boil kettle reaches the preboil volume. At the end of the sparge, measure the pH ad SG of the draining liquid ("end runnings"). Good is < 1.010 and near 6.0 pH. Mine is typically 1.005 and 5.9. That will give you an idea of how well you rinsed the grains.

Sparging... Did you sparge SLOWLY? for 5 gallons, i would recommend a minimum of 30 to 40 minutes. Open the drain to the boil kettle and start dripping or trickling slowly. Valve in sparge water into your recirculating system at the same rate, so that the 2" of fluid is maintained. Your sparge water should be at 168 to 170 for the duration to keep the sugars nice and dissolved, and the slow sparge keeps everything rinsing thoroughly. A super fast sparge will drop efficiency.

And we might as well mention the grind. If you mill your grain at the local shop, someone may have jacked with the settings. Too big and it can have a definite effect on your efficiency. To small and your mash will turn to concrete and nothing will flow through it ("stuck mash" - pain in the a$$). I'm a 0.036" guy, others vary from .030 to 0.040. Run some rice hulls for cheap insurance if it makes you nervous. They are a wonderful thing. A half pound or so per 5 gallons of batch is a good starting point.

Another thing you can do is lightly stir the grain 1 to 3 times during the mash. If the system is working properly, it wort should re-clear itself in a few minutes. This can help assure that all the grain gets a chance at conversion. I also will do a light stir at the end of each mash step and as i'm ramping up to mashout temp. Can i prove it helps? nope. But it makes me feel better

Bet you a beer, your next batch is between 80% and 85% mash efficiency

Man, that is a lot of good info! Thank you!

I do have my own grain mill, and it's set to 0.035. Or at least it was a couple years ago, I've been lazy and haven't checked it in a long time. Should probably do that.

For my next brew I'll make sure I end up with a couple inches of water on top of the mash. I also watched a video of a Brew Magic, so I saw how it was swirling in the tun. I'll try to emulate that...

Thanks again for all the help!

 

[ChzyMnky]

Since mash efficiency is conversion efficiency times lauter efficiency, low mash efficiency can be due to:

1. Low conversion efficiency (not all starch converted to sugar)
2. Low lauter efficiency (usually due to channeling or sparging too fast)
3. A combination of 1 & 2

Obviously, in order to improve low mash efficiency, you need to know whether your situation is 1, 2 or 3.

Conversion efficiency can be calculated by measuring the SG of the wort in the MLT at the end of the mash, using the method here. If your conversion efficiency is less than 90 - 95% you need to work on that. It is possible to achieve 100% conversion efficiency. Finer crush can speed conversion, but needs to be balanced against the need to avoid a stuck sparge. Once you crush as fine as your system will tolerate, then increasing mash time can improve conversion efficiency. For your grain bill and 6 gal of strike water the effective mash thickness for efficiency calculation is 24 qts / 13.75 lb = 1.75 qt/lb. With 100% conversion efficiency, your end of mash wort SG should have been 1.071 - 1.072. Before measuring the end of mash SG, you need to insure that the wort is totally homogeneous. Best way to do this is stir the mash well and then recirc or vorlauf well.

Lauter efficiency is then calculated by dividing your mash efficiency by your conversion efficiency. A well conducted fly sparge should provide better lauter efficiency than a triple batch sparge (based on eff numbers I have seen from well run fly sparges.) For your grain bill, pre-boil volume, and strike volume, a triple batch sparge would have a lauter efficiency of about 88 - 89%, so a "good" fly sparge should be better than that.

One thing you might try is to do a single batch sparge process to see if you get better mash efficiency. If you do, that is an indication that your fly sparge process is lacking. When batch sparging you want to drain everything you can from the MLT and plumbing before you add your sparge water. Then add the sparge water, stir well, and recirc for a while to homogenize. Then run off the sparged wort.

Brew on

Another Doug with good info! Thank you!

I'll try modifying my process with more water in the mash tun and fly sparing more evenly and slowly. If that doesn't work, I'll give batch sparging a try and see what happens.

Thanks again!

 

[augiedoggy]

I noticed huge gains when slowing my sparge process. My process is similar to SoCal Doug's and I've been averaging 91% efficiency since slowing my sparge. I also recirculate very slowly (about 1.5 gallons per minute) which helps against channeling and stuck flow...

 

[ChzyMnky]

I noticed huge gains when slowing my sparge process. My process is similar to SoCal Doug's and I've been averaging 91% efficiency since slowing my sparge. I also recirculate very slowly (about 1.5 gallons per minute) which helps against channeling and stuck flow...

How long do you recommend?

 

[dmtaylor]

One thing will help your efficiency. Crush the wheat malt harder. Wheat has a smaller kernel than barley. You might not get the same low efficiency with 100% barley malt. Crush crush crush. This is the first thing to tackle. I didn't read the other stuff above because this is #1.

 

[augiedoggy]

How long do you recommend?

well on a 5 gallon brew id say at least 15-20 mins I normally do 10 gallons and stretch the sparge out to 30-40 mins also I noticed a couple point gain when doing the mashout while recirculating by bringing my mash up to sparge temps before starting the transfer to the BK and sparge.

 

[SoCal-Doug]

One thing will help your efficiency. Crush the wheat malt harder. Wheat has a smaller kernel than barley.

Totally agree. If you can buy Great Western wheat, the kernels are equal size or larger than barley and you will be fine. If not, crush that tiny wheat twice or adjust your mill.

 

[SoCal-Doug]

well on a 5 gallon brew id say at least 15-20 mins I normally do 10 gallons and stretch the sparge out to 30-40 mins also I noticed a couple point gain when doing the mashout while recirculating by bringing my mash up to sparge temps before starting the transfer to the BK and sparge.

Definitely bring the mash and sparge liquor to mashout temp before sparging. I always thought that was a given. Hot and slow sparging... Get those sugars loose, liquid, and out of the grain.

After a while, you will visually be able to adjust your drain "trickle". It takes a little practice. while you are sparging, keep an eye on the time and your boil kettle volume. Increase or decrease the drain and sparge rate about every 10 to 15 minutes if needed. personally, i target about 30 minutes (gives me some time to measure out my hops and maybe pour a beer and make a sammich).

After sparging, the runnings should be below 1.010 (pretty much clear useless water) and the grain should look like pale dead worn out yuck.