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Mash Problems


read 1647 times • 17 replies • posted 2/21/2011 5:00:31 PM

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badgerben 4400:91
Iíve had a downturn in efficiency for the last few brews, and I need help figuring out whatís happened. Sorry for the length.

My efficiency had been consistently at 65% since switching to all-grain Nov í09. Admittedly not great, but I chalked it up to system limitations. At the time, I was mashing and batch sparing in a 5 gallon kettle for a 3 gallon batch.

All but one beer from the start of all-grain to the problems had an OG of 1.062 or less, putting me at about 9 pounds of grain at 1 quart/lb. The one outlier was 1.074.

In August í10, it nosedived. A IIPA, English Strong, spiced Strong Porter and strong Breakfast Stout all had closer to 50 to 55% efficiency. I did stir the wort before every reading, and gravity checks even after the first gallon and a half were low. Eventually I assumed it was because I was putting in almost 10 pounds of grain, which gave me very little room to add any water to sparge. Possibly worth noting, the IIPA was made a day after a low gravity heather ale that did stick at 65%, ruling out (to me) a water chemistry change for that time frame.

This January, I upgraded my mash tun to a 10 gallon PolarWare and moved my old tun to HLT duty and started fly sparging. So far, Iím having similar problems, but being unfamiliar to fly sparging, Iím wondering if my technique is off.

The sparge arm is a homemade riff on Blichmanís auto sparge. I have a tube that will float on top of the mash water to (hopefully) create an easy whirlpool effect to avoid channeling. I run in enough water to make 2 inches on top of the grain bed before reciruculating.

Iíve brewed an ESB and an 80/-. Both have had comparable experiences, so hereís the 80/-...

88% 6lb 10oz Simpsons Golden Promise
10% 12oz Simpsons Med Crystal
2% Simpsons Pale Chocolate

Filtered water through a carbon filter. Mashed at 154 for an hour, dipping to 150 by the end. Sparged 3.5 gallons in 50 minutes. Readings at 1, 2 and 3.5 gallons were each at 1.039, when 65% eff in a 3 gallon batch should have given me 1.051. Just for kicks, I did an iodine test; near as I could tell, it seemed completely converted. I only have generic pH strips, but it was only slightly more acidic than the 6.0 color.

In the end, I pulled 3.75 gallons and boiled down to about 2.75 and my reading before going to carboy was 1.052.

So, questions:

- Am I likely having the same problem but for different reasons from last fall to now?
- There is a 1.5 gallon dead space under the false bottom. Could that be contributing to the problem in any way?
- When batch sparging, I would frequently run off only to 2.5 or 3 gallons, then top up with plain water before boiling. Should I plan on running off the full amount for boil?
- Should I just run off more wort?
- Do I need to treat the sparge water with anything after filtering?
- Do I need to sparge slower?
- Is there anything in my water that the filter is stripping out that could be screwing with conversion or
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SpringsLicker 3133:131
Have you switched malt brands?
2/21/2011 5:28:10 PM

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DA 1
a few things that come to mind (granted I just quickly read through your post)

If youíre fly sparging plan on 45-60 minutes to get through the sparge, need to give the sparge water time to soak up the sugars, I try to hit 180 with the sparge water.

I batch sparge as well and get above 70% efficiency on most beers below 1.060 in a crappy igloo cooler. Make sure to stir really well after each infusion. If you changed your malt up maybe check to make sure there are no big dough ball clumps floating around, I know some malt tens to clump up more for me. You can also try doing more infusions.

Do you mill your own grain? Or did you change up where you were buying/milling your grain? Iíve purchased malt and milled it at a local homebrew shop and had terrible efficiency, when I got my own mill I went from 60 to 70%. Crush can be really important.

Also, it sounded like you did a run of strong beers that got poor efficiency. Thatís pretty common with big beers. Adjust your efficiency accordingly.
2/21/2011 5:45:29 PM

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DA 1
Originally posted by badgerben
- There is a 1.5 gallon dead space under the false bottom. Could that

I just noticed this, 1.5 gallons of dead space in a 3 gallon batch? Any way to drop your dip tube down to pick this up? you could be losing some good sweet wort here.
2/21/2011 5:47:47 PM

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badgerben 4400:91
Thanks for the possibilities.

Havenít really changed brands. Pretty much Simpsons all the way.

My sparge water definitely isnít that hot, probably closer to 170. I crush them as I buy them at Northern Brewer, no more than a week before brewday. Theyíve set the grinder at... .35 microns? Whatever used to be the posted recommendation is what itís always set at now.

I definitely make sure I donít have clumps of malt. Made that mistake the first time around.

As for the dead space, I may have mis-named that. The kettle will physically drain all but about a quarter inch from the bottom, but thereís a gallon and a half between the bottom of the kettle and the bottom of the grain bed. So if I calculate 1.5 quarts per pound, thereíd be an extra 6 quarts under the grain bed. Iím not sure if that screws up the chemistry.

Although, if the iodine test was correct in that conversion was done, maybe it is still just sparging too fast and too cool.
2/21/2011 9:52:01 PM

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DA 1
Originally posted by badgerben
Thanks for the possibilities.

Havenít really changed brands. Pretty much Simpsons all the way.

My sparge water definitely isnít that hot, probably closer to 170. I crush them as I buy them at Northern Brewer, no more than a week before brewday. Theyíve set the grinder at... .35 microns? Whatever used to be the posted recommendation is what itís always set at now.

I definitely make sure I donít have clumps of malt. Made that mistake the first time around.

As for the dead space, I may have mis-named that. The kettle will physically drain all but about a quarter inch from the bottom, but thereís a gallon and a half between the bottom of the kettle and the bottom of the grain bed. So if I calculate 1.5 quarts per pound, thereíd be an extra 6 quarts under the grain bed. Iím not sure if that screws up the chemistry.

Although, if the iodine test was correct in that conversion was done, maybe it is still just sparging too fast and too cool.

170 shouldnít be too much of a problem, but if itís going too fast it would hurt your efficiency, try that and see if it fixes it.

As for the dead space, with the 1.5 gallons under the grain bed, do the grains on top still sit in water? Maybe try mashing a bit thinner if the grains on top are sitting above the water level and stirring a few times during the mash to make sure the liquid in the dead space moves around. A thinner mash may help your efficiency as well.

2/22/2011 9:03:49 AM

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NobleSquirrel 3437:209
Originally posted by badgerben
Thanks for the possibilities.

Havenít really changed brands. Pretty much Simpsons all the way.

My sparge water definitely isnít that hot, probably closer to 170. I crush them as I buy them at Northern Brewer, no more than a week before brewday. Theyíve set the grinder at... .35 microns? Whatever used to be the posted recommendation is what itís always set at now.

I definitely make sure I donít have clumps of malt. Made that mistake the first time around.

As for the dead space, I may have mis-named that. The kettle will physically drain all but about a quarter inch from the bottom, but thereís a gallon and a half between the bottom of the kettle and the bottom of the grain bed. So if I calculate 1.5 quarts per pound, thereíd be an extra 6 quarts under the grain bed. Iím not sure if that screws up the chemistry.

Although, if the iodine test was correct in that conversion was done, maybe it is still just sparging too fast and too cool.


Couple of things Iíd take into account: Mash pH can be a culprit of poor efficiency. I would look into that because you may not be releasing enough of the sugars. Also, have you taken gravity readings of your runoff? I would check throughout your runoff and see if that is where youíre having issues. You may just be leaving a bunch of sugar in the tun...
2/22/2011 9:27:58 AM

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badgerben 4400:91
The grains are definitely all in the mash water. For yesterdayís brew, I had about 8 pounds of grain mixed with 12 quarts water. I added an extra 6 quarts to account for the gap from bottom to false bottom. So where the grains actually mix, it was a 1 pound to 1.5 quart ratio; in the entire kettle, it was closer to 1 pound to 2.25 quarts.

I definitely do gravity readings. Theyíre low from the first test around 1.5 gallons. Maybe I will need to get a pH tester. My water is pretty close to 7 before mashing, at least according to the city report.
2/22/2011 9:42:09 AM

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DA 1
Originally posted by badgerben
The grains are definitely all in the mash water. For yesterdayís brew, I had about 8 pounds of grain mixed with 12 quarts water. I added an extra 6 quarts to account for the gap from bottom to false bottom. So where the grains actually mix, it was a 1 pound to 1.5 quart ratio; in the entire kettle, it was closer to 1 pound to 2.25 quarts.

I definitely do gravity readings. Theyíre low from the first test around 1.5 gallons. Maybe I will need to get a pH tester. My water is pretty close to 7 before mashing, at least according to the city report.

You could also try a product called Fivestar 5.2 Stabilizer, itís like a PH buffer you add in to your mash. Iíve never used it, but if the mineral additions to balance you PH seem overwhelming it may be an easy way to go.
2/22/2011 10:12:27 AM

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SpringsLicker 3133:131
Another one I ran across a few years back was that a fellow brewer had dropped his dial-type thermometer on the floor. After several problematic batches, he checked his thermometer and discovered that the drop had thrown it off by several (apparently critical) degrees. After a re-calibration his problems disappeared. I like to check mine on occasion even if I havenít dropped one. I check them both in a stabilized ice-water bath which should yield a 32 degree F reading and in boiling water which at my altitude yields a 210 degree F reading. My thermometers were about $20 which will be expensive to some of you, yet even these arenít perfectly accurate over the entire range. Just be aware of how they are performing and adjust accordingly. I calibrate to the high end if they are off at one of the two constants.
2/22/2011 11:36:45 AM

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NobleSquirrel 3437:209
Originally posted by badgerben
The grains are definitely all in the mash water. For yesterdayís brew, I had about 8 pounds of grain mixed with 12 quarts water. I added an extra 6 quarts to account for the gap from bottom to false bottom. So where the grains actually mix, it was a 1 pound to 1.5 quart ratio; in the entire kettle, it was closer to 1 pound to 2.25 quarts.

I definitely do gravity readings. Theyíre low from the first test around 1.5 gallons. Maybe I will need to get a pH tester. My water is pretty close to 7 before mashing, at least according to the city report.


Are you doing a recirculation at all prior to running off? if you have the settling youíre talking about, that could explain the issues youíre talkinga bout. Youíre never giving the water at the bottom a chance to pull sugars from the malt, or at least not much of a chance. Iíd make sure that you are recirculating the first gallon or so prior to running off. That should help some.
2/22/2011 12:23:17 PM

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