Help with Mash Efficiency/Sparge

[BigJay13]

I've done 4 batches on my eHERMS system--2 5g and 2 10g. The latest batch, a German pils, was 10 gallons. I sparged at a rate of 1 quart/minute--held pretty consistently throughout--and had a final runnings of 1.035. My MLT has a false bottom and the outlet is simply a port on the side--there are no pickup points with a dip tube in the middle. I use a blichmann autosparge to lay the spare water on top. I had a sparge runnings pH of 5.6 as was my mash pH adjusted with lactic acid. I'm really at a loss as to why my final runnings were so high. Before I started using the eHERMs system and was on propane my final runnings would consistently drop close to or below 1010 so I would need to watch for it. I used a hydrometer with the samples cooled down close to room temp then adjusted using the beer smith hydrometer adjustment tool. OG of the beer was 1.053.

Further information weather it's useful or not. 60 minute mash with a ramp up to 165ish to mash out when it was complete. After about 15 minutes I started recirculating the wort in the mash through the coil and held 149. 60 minute boil. 20 lbs Wyermann Pils Malt and Hallartau hops in the boil.

 

[catalanotte]

Have you investigated channeling through the MLT? Seems to be the most likely issue as the rest of the data and procedures look good, assuming grain crush is consistent from prior batches on the old set up that yielded better efficiency. When you're done and drain out the MLT, can you see any sign of channels in the grain bed on the side of the valve? The recirculation during the mash may be causing more channeling than you were getting when only doing a sparge, which could explain the change with the same MLT. Switching to a center pick up on your false bottom may help. You could also break up the grain bed a couple times during the mash and let it resettle prior to the sparge. Might get a small drop in wort clarity, but a big gain in efficiency.

 

[BigJay13]

Have you investigated channeling through the MLT? Seems to be the most likely issue as the rest of the data and procedures look good, assuming grain crush is consistent from prior batches on the old set up that yielded better efficiency. When you're done and drain out the MLT, can you see any sign of channels in the grain bed on the side of the valve? The recirculation during the mash may be causing more channeling than you were getting when only doing a sparge, which could explain the change with the same MLT. Switching to a center pick up on your false bottom may help. You could also break up the grain bed a couple times during the mash and let it resettle prior to the sparge. Might get a small drop in wort clarity, but a big gain in efficiency.

I did stir several times and I do think the suction from the pump is causing the grain bed to compact on that side of the pot. I think I'll get a center dip tube and slow the flow rate down during recirc--do you think that would be enough? I can also look into creating multiple pickups. Would the channeling cause the last runnings to be that high in gravity?

 

[doug293cz]

I did stir several times and I do think the suction from the pump is causing the grain bed to compact on that side of the pot. I think I'll get a center dip tube and slow the flow rate down during recirc--do you think that would be enough? I can also look into creating multiple pickups. Would the channeling cause the last runnings to be that high in gravity?

I would expect with channeling, you would get lower final runnings SG, since you over-rinse in the channels (where most of the liquid flows), and under-rinse in the no/low flow regions.

165°F is a bit low for a mash-out, so you could have been getting additional starch conversion during the sparge, if the enzymes weren't fully denatured. A quick simulation (using triple batch sparge) indicates that your conversion efficiency was relatively low (assuming that your sparge wasn't the issue), about 85% - 87%. This would mean that there was residual starch that could convert during the sparge. If you had incomplete conversion during the mash, and continued conversion during the sparge, your initial run-off SG would be low, and your final run-off SG would be higher than expected.

Can't make a definitive statement about conversion efficiency, because that requires an accurate strike water volume measurement and an SG measurement prior to starting run-off (in addition to the grain bill weight, which you did supply.)

Brew on

 

[BigJay13]

I would expect with channeling, you would get lower final runnings SG, since you over-rinse in the channels (where most of the liquid flows), and under-rinse in the no/low flow regions.

165°F is a bit low for a mash-out, so you could have been getting additional starch conversion during the sparge, if the enzymes weren't fully denatured. A quick simulation (using triple batch sparge) indicates that your conversion efficiency was relatively low (assuming that your sparge wasn't the issue), about 85% - 87%. This would mean that there was residual starch that could convert during the sparge. If you had incomplete conversion during the mash, and continued conversion during the sparge, your initial run-off SG would be low, and your final run-off SG would be higher than expected.

Can't make a definitive statement about conversion efficiency, because that requires an accurate strike water volume measurement and an SG measurement prior to starting run-off (in addition to the grain bill weight, which you did supply.)

Brew on

Interesting...So I've got 3 gallons of dead space below my false bottom. I mashed in with about 9 gallons of water because of that--to be honest it was a little thin because I misread the sightless. And the sparge was about 9.5. So maybe I mashed thin, it didn't convert fully, and I "under sparged" because of the thin mash?

I'm beginning to think I may have better success getting a new false bottom with a dip tube through the top of it or switching to a manifold of some kind so the mash can have less water in it. That and much less flow during the recirc.

 

[catalanotte]

I did stir several times and I do think the suction from the pump is causing the grain bed to compact on that side of the pot. I think I'll get a center dip tube and slow the flow rate down during recirc--do you think that would be enough? I can also look into creating multiple pickups. Would the channeling cause the last runnings to be that high in gravity?

Now that I think about it, channeling the sparge water would likely result in both low gravity runnings, low efficeincy, and low OG. But you sound like your overall efficiency is pretty good. If you are getting 10+ gal to the fermenter at an OG of 1.053 from 20 pounds of malt sounds your dong good. I am guessing if you collected say 10.5 gal (allow for losses) wort to the fermenter, your overall brewhouse efficiency is about 75%, this is pretty good.

Figured 10.5 gal * 53 pts per gal = 556 pts Potential is 20 lbs * 37 ppg ( estimate) = 740 pts Brewhouse Eff = 556/740 = 75.1%

The high gravity of the runnings just don't add up if you made 10-11 gallons of wort at a post boil OG of 1.053.

Here is a question, are you measuring the runnings as they are coming out of the hose towards the tail end of the sparge, or are you sampling later from what that has been sitting on the grains in the MLT for a while without circulation? That last bit of water, while sitting and steeping the remaining grains will show a spike in gravity, but if you were resume a normal sparge, it would quickly drop back down to a much lower gravity. Just a thought since the efficiency and gravity of final runnings don't add up.

 

[BigJay13]

Now that I think about it, channeling the sparge water would likely result in both low gravity runnings low pre boil gravities. But you sounds liek your overall efficiency is pretty good. If you are getting 10 gal at an OG of 1.053 from 20 pounds of malt sounds pretty good. I am guessing if you collected say 10.5 gal (allow for losses) wort to the fermenter, your brewhouse efficiency is about 75%, this is pretty good.

The high gravity of the runnings just don't add up if you made 10-11 gallons of wort at a post boil OG of 1.053.

Here is a question, are you measuring the runnings as they are coming out of the hose towards the tail end of the sparge, or are you coming back a bit later and drawing a sample out of the bottom of the MLT to test after it has sat for while without circulation? That last bit of water, while sitting and steeping the remaining grains will show a spike in gravity, but if you were resume a normal sparge, it would quickly drop back down to a lower gravity. Just a thought since the efficiency and runnings gravity don't add up.

I grabbed the sample as the pump sputtered the last bit of wort into the kettle. It’s not adding up for me either. BUUUT I think Doug is right that I started transferring before conversion was complete. I had written down 1050 as first running gravity thinking it didn’t make sense, but if it was still converting and was going up through the sparge I guess it makes sense. Idk I’m really at a loss. I used a hydrometer for everything. The same hydrometer.

 

[catalanotte]

Idk I’m really at a loss. I used a hydrometer for everything. The same hydrometer.

If you got 10 gal of 1.053 beer out of this, and it ferments well, perhaps you let this go and keep doing what your doing.

 

[BigJay13]

If you got 10 gal of 1.053 beer out of this, and it ferments well, perhaps you let this go and keep doing what your doing.

True, but I’ve been brewing AG for 13 years on a few different systems and this is the first time I’ve had anything weird.