Author Topic: Conversion Efficiency  (Read 3888 times)

Offline neemox

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Conversion Efficiency
« on: November 21, 2012, 10:30:32 AM »
So, losing my mind a little bit...

I'm having a hard time getting consistent efficiency and I think it is in my conversion. I've been making a lot of adjustments to my process in an attempt to get above the 54% efficiency mark where I have been sitting. I've calibrated about 30 thermometers, 3 hydrometers, re-evaluated my grain crush, checked mash pH..... I've really been trying to nail this down, and I seem to be getting no where.

This past weekend I brewed what was supposed to be a 5.5 gallon batch. I used beercalculus.com to build my recipe, I left the efficiency setting at 75, thinking that all the small changes I had made would add up. According to BC, my OG with a 75% efficiency should have been 1.079. (12lbs 2-row, 2.5 lbs specialties) I mash in an igloo cooler with a 1.5 qt/lb water:grain ratio. This time, that ratio was even a bit higher because I wasted a lot of heat really thoroughly stirring my mash around to wet all of the grains, so I had to add a little more than a galolon of boiling to the mash, so my ratio was closer to  1.94. The pH of my mash was 6.0 according to my pHydrion strips. A little high, but I didn't have any citric acid lying around, so I went with it. I mashed for 60 minutes, stirring about 4 times over the hour. Temperature was still good when I started my lauter.

Now, the real problems. I collected my first runnings, and let them cool while I was lautering. At 90°F, the gravity was 1.050. In my mind, my first runnings should have been over 1.080. Feel free to tell me I'm wrong here. I was trying to collect 6.5 gallons, and then boil for an hour. I fly sparged with 170°F water until the runnings were plainly not sweet, but at this point I had collected 8.5 gallons. Even after overlautering, my total gravity in the 8.5 gallons was only 1.035. In my mind, 35 points in 8.5 gallons only equals 54 points in 5.5 gallons. (Again, feel free to tell me I'm wrong about this math) So, 1.054 is a far cry from 1.079. So I changed everything up and tried to add in some extra points with some DME. Added half a pound to the boil (all I had on hand thankfully), and then boiled for an hour before I started my hop addition. After being pretty fed up with what should have been a perfectly good brew day, I accidentally boiled for too long, and so I ended up with only 4 gallons of chilled wort, but it was at 1.084. Had I hit my target volume, and not added the DME (only 3.3 points in 5.5 gallons me thinks) I would have been at 1.058. Damn close to my first runnings, and WAY under my target.

So, now that you have read my overly long brew day story, what other information can I give you so you can tell me what the hell I'm doing wrong. I got lucky on this one that I will recover a beer close to what I wanted in the first place, but it sure would be nice to have the extra 1.5 gallons of beer when I work this hard for it. Also, I'd love to be able to brew a beer twice and get the same beer out. So far, reproduciblility is a long ways off.

Thanks so much in advance.

Offline VinS

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Re: Conversion Efficiency
« Reply #1 on: November 21, 2012, 10:39:49 AM »
1. Did you stir your runnings? If not that can give you a low reading. 2. Why did you keep collecting when you should of ended with around 7 to7.5 gallons that extra water will lower your starting gravity and does nothing for you.
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Offline euge

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Re: Conversion Efficiency
« Reply #2 on: November 21, 2012, 10:56:30 AM »
You may be channeling. What type of manifold/mashtun setup do you have?
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Online denny

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Re: Conversion Efficiency
« Reply #3 on: November 21, 2012, 11:11:42 AM »
For one thing, I think the OG estimate was off.  I get 1.066 in Promash using your grist.
Life begins at 60.....1.060, that is!

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Offline neemox

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Re: Conversion Efficiency
« Reply #4 on: November 21, 2012, 11:12:30 AM »
1. Did you stir your runnings? If not that can give you a low reading.

I did stir the runnings, I wanted to make sure and get an accurate value.
2. Why did you keep collecting when you should of ended with around 7 to7.5 gallons that extra water will lower your starting gravity and does nothing for you.
The runnings were still sweet, and nervous that I was looking at another 50% efficiency, I wanted to get all the sugars I could. Once I was over the 6.5 mark, I knew it would be a long boil to concentrate it. I figured, may as well boil a little longer. (Although I probably paid for the sugar with propane)

You may be channeling. What type of manifold/mashtun setup do you have?
I have a 10 gallon igloo beverage cooler with a false bottom screen. Would channeling affect my first runnings? My understanding was that channeling would produce issues with the sparging/lautering.

Offline euge

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Re: Conversion Efficiency
« Reply #5 on: November 21, 2012, 11:17:24 AM »
How much are you lautering before you start the sparge? For instance are you draining the entire amount first or just establishing the flow rate to set the grain-bed and then starting the sparge?
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Offline neemox

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Re: Conversion Efficiency
« Reply #6 on: November 21, 2012, 11:18:12 AM »
For one thing, I think the OG estimate was off.  I get 1.066 in Promash using your grist.

Hmm, I was wondering if 12 lbs wasn't light for this target. What efficiency considerations does promash make? Using data from Palmer's book and a 75% efficiency I calculate 12lbs*27ppg/5.5g=1.059. All of a sudden, I am starting to think that beercalculus includes specialty grains in their calculations for OG....  Anyone else experienced this? Maybe this is my only issue, not doing the math the long way.

Offline neemox

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Re: Conversion Efficiency
« Reply #7 on: November 21, 2012, 11:20:38 AM »
I drain until the mash level is just above the grain, then start siphoning in sparge water at a rate as close to equal as I can get it. I definitely started my sparge at a rate quicker than I wanted (built up about 1-2 gallons on top of my grain bed) but I don't think that should have add a dramatic impact?

Online denny

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Re: Conversion Efficiency
« Reply #8 on: November 21, 2012, 11:22:53 AM »
For one thing, I think the OG estimate was off.  I get 1.066 in Promash using your grist.

Hmm, I was wondering if 12 lbs wasn't light for this target. What efficiency considerations does promash make? Using data from Palmer's book and a 75% efficiency I calculate 12lbs*27ppg/5.5g=1.059. All of a sudden, I am starting to think that beercalculus includes specialty grains in their calculations for OG....  Anyone else experienced this? Maybe this is my only issue, not doing the math the long way.

I entered 12 lb. of 2 row pale at 36 ppg and 2.5 lb. of C60 at 34 ppg to simulate your grist.  At 75% I get 1.071 for your OG.  I made a mistake earlier and had PM set for 5.5 gal., not 5.
Life begins at 60.....1.060, that is!

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Online denny

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Re: Conversion Efficiency
« Reply #9 on: November 21, 2012, 11:24:14 AM »
I drain until the mash level is just above the grain, then start siphoning in sparge water at a rate as close to equal as I can get it. I definitely started my sparge at a rate quicker than I wanted (built up about 1-2 gallons on top of my grain bed) but I don't think that should have add a dramatic impact?

Try batch sparging next time.  That will show you if your lauter system is the culprit.  Have you checked your conversion efficiency via Kai's website?

http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency#Determining_Conversion_Efficiency
Life begins at 60.....1.060, that is!

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Offline euge

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Re: Conversion Efficiency
« Reply #10 on: November 21, 2012, 11:32:13 AM »
My understanding is that fly-sparging can be enormously tricky to dial in. I batch-sparge and get excellent results.
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Offline mmitchem

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Re: Conversion Efficiency
« Reply #11 on: November 21, 2012, 11:35:19 AM »
My understanding is that fly-sparging can be enormously tricky to dial in. I batch-sparge and get excellent results.

Not to mention it is super fast. Quick sparge for sure. I got ~83% efficiency this last weekend on a Munich Dunkel. Works for me :)
Michael P Mitchem
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Offline neemox

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Re: Conversion Efficiency
« Reply #12 on: November 21, 2012, 11:36:49 AM »
I was trying to collect 5.5 gal, but I think I don't think beercalculus is very good at factoring that in.

This is actually the first time I have tried fly sparging, I usually batch sparge with the same results. I was trying the continuous sparge to see if investing in a proper fly sparging set-up might help.

According to Kai's formulas, I had a conversion efficiency of 99%, but I'm not sure I understand how that could be possible. Does his table assume qts of water per pound of base malt? or the entire grain bill?

Offline neemox

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Re: Conversion Efficiency
« Reply #13 on: November 21, 2012, 11:43:42 AM »
My understanding is that fly-sparging can be enormously tricky to dial in. I batch-sparge and get excellent results.

Not to mention it is super fast. Quick sparge for sure. I got ~83% efficiency this last weekend on a Munich Dunkel. Works for me :)

These were my understandings as well, which is why I used to batch sparge, but I've never seen anything that looked like 83%. When you say quick, how quick. When I batch sparged, I drained my tun, added sparge water, stirred it up, then let it sit for about 30 minutes before draining again. Was I wasting my time with the "sparge rest"? I'll brew another bacth this weekend and go back to batch sparging.

Offline euge

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Re: Conversion Efficiency
« Reply #14 on: November 21, 2012, 11:48:52 AM »
I let it sit for about 10 minutes to settle down after adding the second sparge and stirring. Seems to set better that way but others don't wait so long I think. Probably doesn't make a difference. ::) Waste of time is really subjective so I hate to speculate on that. I cut corners where I believe it is appropriate.
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman