the efficiency troubleshooting continues....HELP!

[AN_TKE]

Anyone have any ideas on how to increase mash efficiency? I can't seem to get higher than 60%, even when my process has the following going for it:

- I can stabilize temp at whatever the recipe calls for
- I have a low mash pH and a starch test indicates complete conversion
- I fly-sparge (after mashing out) and am able to get at least 2" of totally clear water above the grain bed before i stop sparging
- I can "wring out" the grain with a potato masher and end up with a fairly dry bucket of grain
- I can boil down to less than 5 gallons (so i doubt dilution is the problem)

And I still have poor efficiency! Argh!

What would you do?

Thanks!

Heath

 

[ajf]

Welcome to the forum.

I posted this a few days ago in response to a similar question:


First, verify that your sparge is suspect.
If you are batch sparging, take a sample of the last batch, and measure the gravity after cooling (or use a refractometer). I get a gravity of ~1.020 and a mash efficiency of about 80%
If you are fly sparging, measure the gravity of your final runnings, then add an extra gallon or so of 170F water (if your grain bed is dry - not required if the sparge is wet enough to stir), stir well, and measure the gravity again. My final runnings come out at 1.008 - 1.010, and after adding extra water, and stirring, the gravity drops.
If your gravity rises, you have channeling caused either by faulty procedures, and/or by unsuitable equipment.
Methods to improve sparge efficiency:
1. Keep the grain bed at 168 - 170F throughout the sparge. This may require hotter water for the first batch of a multi-batch sparge, or a mash out prior to starting the sparge. (Use the 5.2 buffer in the sparge water to prevent tannin extraction problems.)
2. Sparge slower. This can have a dramatic effect with fly sparging if you are sparging too fast and causing channeling. It probably has a very minor effect when batch sparging.
3. Stir well before commencing the sparge, then vorlauf until the runnings contain no noticeable grain particles.
4. Make sure your thermometer is accurate by calibrating in boiling and iced water. (If you have an inaccurate digital thermometer, try replacing the battery.)
If the sparge checks out OK, try an iodine test to check for complete conversion. A longer mash will even compensate to some extent for an inadequate grain crush.

Hope this helps.

-a.

 

[menschmaschine]

What kind of MLT and filtering method (braid, bazooka, etc.) are you using? Oh, and check your crush.

 

[Got Trub?]

What kind of MLT and filtering method (braid, bazooka, etc.) are you using? Oh, and check your crush.

This is usually the biggest variable in efficiency.

GT

 

[jagg]

Well, looks like we are inthe same boat, I did Ed's Stone Ruination clone today and hit 67%, this was my second AG, the first was Ed's haus Ale, it was a 11 gallon batch, hit 73% on that one, the only difference was the Stone was a 5.5 gallon, I lost over 7*f over the hour, I guess the lesser volume in the tun caused this, Ill keep watching this post to get some ideas, thanks, you saved me from having to post this same question.

 

[Bobby_M]

I'm keeping an eye out for what your separation medium is. If it's a braid, that's suspect. If not, I'm guessing crush, sparge temp, or sparge speed.

 

[AN_TKE]

Thanks for all of the advice. to answer a few questions (and ask a few more):

- I fly sparge with about 180-degree water into my mash ton. I can't recall what the temp is of the mash while i sparge, but i do mash out, stir like mad, and the hot water shower is plenty hot enough (i think). I know i had over 160-degrees, but i am not sure exactly what it was last time. Good idea to buffer the sparge water - i'll try it.
- My MLT and HLT are 10 gal, circular rubbermaid coolers. The HLT has an electric element for heating. I gravity drain the HLT into a little bucket with holes on the bottom to spread the flow over the water on top of the grain.
- My seperation method is the bottom 3 inches of a bucket (upside down)with a few hunderd 3/32" holes, acting as a false bottom. Then i have a tube from the middle, through the bucket, to the discharge valve. I don't get any debris in the pot unless it is dissolved. This seems to work great for seperation because the first vorlauf sample never has any debris in it. (am i using vorlauf correctly?)
- I am curious about channeling: I have read that if you maintain a few inches of water above the top of the grain, then channeling shouldn't be an issue. Does that sound right? It seems like the turbulance of the water on top, along with its equal pressure over the top of the grain, would adequately distribute the runnings? What do you all do to prevent channeling?
- It takes me about 20-25 min to sparge approx 7.5 gal to boil. This is regulated by 1/2" ball valves on the HLT and MLT, open about half way. Maybe this is too fast? How long do you all take to sparge?
- My grain is milled for me at the local shop, where i have bought all of my grain so far...except for a batch i bought last week at a new shop that opened in town. I'll have to see if the different milling will have any effect - good idea!

So, on my next batch i'll observe sparge grain temp and I'll try the runnings gravity test suggested by ajf. I'll increase sparge time to at least 30 min and then see if ajf's test shows me anything. I guess if there is channeling, you can sparge all day and still not get what you are looking for.

WooHoo Beer!

Thanks again,
Heath.

 

[wildwest450]

Im not a fly sparger, but im sure that 20minutes is way to fast to achieve good efficiency, your probably leaving a lot of sugars behind. I believe most die hard fly spargers around here go from 45minutes to an hour. That's why I prefer batch sparging, way less time involved, and good efficiency.(not trying to start a flame war)

 

[Bobby_M]

not trying to start a flame war)

Yes you are. Down with the fly. Long live the batch. ;-)

 

[ajf]

I fly sparge for 60 - 90 minutes for 5g batches in a 5g cooler. This probably gives me a deeper grain bed than you have, which should help to eliminate channeling. I would think that your false bottom could be the cause of low efficiency. If you have 3 inches of dead space under the bottom in a 10-g cooler, your heaviest wort will collect below the bottom, and never make it into the brew kettle. I use a Phil's phalse bottom see http://www.listermann.com/Store/Details.asp?ID=935 for the 10g size. This leaves very little dead space, and gives me 85% efficiency. -a.

 

[wildwest450]

Down with the fly. Long live the batch. ;-)

Viva la batch!:rockin:

 

[menschmaschine]

I fly-sparged today for 30 minutes and got 93% efficiency. This is the second time I tried a faster fly-sparge and still got high efficiency. Maybe next time, I'll open up both valves full-bore and see what happens!

No matter what I do to try to screw up my efficiency, it's always high. (I'm not miscalculating it and all my fermentables were weighed accurately.) I'm beginning to form a theory about exactly how I fly-sparge that boosts my efficiency so much.

 

[AN_TKE]

thanks for the ideas. I think i'll do a batch sparge next time as advised. My setup really won't have to change at all, and it might still only take the 20-25 min i am used to. I will also look into the false bottom upgrade suggested by ajf - i do seem to have a bit lost, maybe that will make a difference!

Batch sparge: drain all sweet wort possible into boil pot, add enough water at about 180+ to remaining grain to re-float the grain (or half vol. needed for post boil vol.), stir like mad and then drain again, repeat. start with a thicker mash to allow more sparge volume. any other steps i should take? Should i drain at a slow rate or does that matter? Open that sucker all the way?

Another question: After reading Bobby_m's all grain description on his website i wonder about boil length. I have been pulling recipes from Clone Brews by Szamatulski and every batch calls for a 90 minute boil. Is a boil time over 60 min beneficial for anything aside from evaporation? I thought that hop utilization peaks after 60 min and i wonder if any other of the reasons for boiling might need more than 60 min. It would be nice to cut a half hour out of brew day.

I have to say - as a new guy to this forum, I am impressed at the number of replies and how quickly they get posted. Thanks again!

 

[Bobby_M]

I typically only boil for 70 minutes which is a sweet spot for 1.5 gallons of boil off for me. However, if I have more than say 30% pils malt, I boil for 90 to drive off the DMS precursors.

 

[AN_TKE]

so your boil time is determined by the amount you want to have remaining in the kettle - so long as you have 60 min under your belt?

sorry for the ignorance, but what is a DMS precursor?

 

[jds]

so your boil time is determined by the amount you want to have remaining in the kettle - so long as you have 60 min under your belt?

sorry for the ignorance, but what is a DMS precursor?

https://www.homebrewtalk.com/wiki/index.php/DMS

Cliffs Notes: DMS is dimethylsufide. It lends a cooked corn flavor, which is undesirable in some ales. It forms during the boil, which is one reason we boil wort uncovered. Pilsner malt gives rise to more DMS during the boil than pale malts, hence the longer boil with Pilsner malts to drive off DMS.