Author Topic: Dramatic swings in mash efficiency  (Read 907 times)

Offline qm3k

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Dramatic swings in mash efficiency
« on: July 04, 2014, 10:36:48 AM »
Hi all,

I recently made a few equipment changes to my system and am having trouble with my mash efficiency.  I know that there will be a period of instability until I brew more with the new equipment. I have brewed 2 batches so far and have had a very large variance in my mash efficiency...72% for the first, 66% for the second. I expected my numbers to be a little wonky for a while, but that's a pretty big spread.

I switched my MLT from a 10 gallon Polarware and false bottom to a Blichmann 10 gallon Boilermaker with AutoSparge and false bottom. I used to get 75% consistently with my old system. Has anyone had similar drops/variances with that equipment?

The beers I brewed were an amber (72%) and a hefeweizen (66%).

If it isn't the equipment change, where should I be looking in my process to get things more consistent?

Thanks.

Offline duboman

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Re: Dramatic swings in mash efficiency
« Reply #1 on: July 04, 2014, 10:49:48 AM »
If everything else in your process is the same but the equipment then that's where the issue lies. IMO 2 batches of 2 completely different recipes is not enough to dial something in.

I would try and brew the same recipe a few times and see what you get. If the same recipe produces the same numbers each time then use that as your efficiency calculation moving forward
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Offline qm3k

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Re: Dramatic swings in mash efficiency
« Reply #2 on: July 04, 2014, 11:00:23 AM »
If everything else in your process is the same but the equipment then that's where the issue lies. IMO 2 batches of 2 completely different recipes is not enough to dial something in.

I would try and brew the same recipe a few times and see what you get. If the same recipe produces the same numbers each time then use that as your efficiency calculation moving forward

Thanks. I figured I'd have to brew a lot more to get my numbers consistent...the degree of the variance this time was just a little unnerving. Cheers!

Offline Kinetic

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Re: Dramatic swings in mash efficiency
« Reply #3 on: July 04, 2014, 12:12:06 PM »
Who crushes your grain?  Ideally, it should be you, if you want to maximize efficiency and consistency.

The other thing you need to dial in is the mash pH, if you haven't already.

Offline mabrungard

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Re: Dramatic swings in mash efficiency
« Reply #4 on: July 04, 2014, 12:42:35 PM »
I have had efficiency reductions when using high percentage of wheat malt in my grist. A Hefe would display that. I expect that when you brew your next all barley beer, the efficiency will return. I don't know why wheat does this, but I accommodate for the efficiency reduction in the recipe formulation.
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Offline erockrph

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Re: Dramatic swings in mash efficiency
« Reply #5 on: July 04, 2014, 01:18:07 PM »
Who crushes your grain?  Ideally, it should be you, if you want to maximize efficiency and consistency.

+1 - my efficiencies were all over the place until I started milling my own grain
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Offline HoosierBrew

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Re: Dramatic swings in mash efficiency
« Reply #6 on: July 04, 2014, 02:13:03 PM »
Sounds mostly like the new equipment/ system to me, assuming you were consistent with the prior 75% efficiency. If you weren't consistent in the 75% beforehand, I'd point at least partially to crush. I know because I've been there - I wanted to pull my hair out back in the 90s when I knew I had my process down to consistency, but didn't have that in efficiency. It was the inconsistency in the crush I got from my LHBS that was the final variable. For a few years I got them to double crush my grain and got a bump up to ~ 80% and then finally broke down and bought a mill, where I could obviously mill to my satisfaction.
But, Martin is right in terms of efficiency with wheat - it goes down. No surprise with the efficiency loss there. Best to 'build' in a few points of loss in to your recipe. Good luck !
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Offline ynotbrusum

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Re: Dramatic swings in mash efficiency
« Reply #7 on: July 06, 2014, 06:02:36 AM »
Even milling your own grain can result in variances, if your gap slips a bit.  Just happened to me and it was the first thing I found.  Like Martin says, also, wheat caused it for me previously on a 50% wheat grist, so adjust the bill accordingly....
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Offline S. cerevisiae

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Re: Dramatic swings in mash efficiency
« Reply #8 on: July 06, 2014, 06:27:29 PM »
Other than a reduction in dead space, I am curious as to why you moved from a 10-gallon Polar Ware kettle with a false bottom to a 10-gallon Blichmann kettle with a false bottom.  I would never trade my 10-gallon 361BP for a 10-gallon Blichmann kettle. However, then again, I prefer to own kettles that have welded fittings.
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Re: Dramatic swings in mash efficiency
« Reply #9 on: July 07, 2014, 06:18:33 AM »
Martin brings up a good point about the wheat in your recipe. Wheat kernals are usually smaller than barley kernals and often need to be crushed at a smaller mill setting. Rye malt is smaller still.

As was also mentioned, pH will definitely affect your efficiency. A good pH meter is a dandy brewing item to own. Essential? No. But certainly helpful.
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Offline mattybrass

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Re: Dramatic swings in mash efficiency
« Reply #10 on: July 08, 2014, 09:18:55 AM »
+1 again to milling your own grain, and to the wheat kernels being smaller. Crushing your own does help alot.

Also i +1 the post saying to brew the same recipe 2x in a row making sure you are noting both times to compare all the variables, time, ph, temp etc.

Offline goschman

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Re: Dramatic swings in mash efficiency
« Reply #11 on: July 09, 2014, 10:08:23 AM »
I am in the same boat as the OP and it drives me crazy! I mill my own grains and I average 68% efficiency and normally get between 65-71%.

I am brewing right now and just took my preboil gravity. A whopping 59.8% efficiency! This did have a lot of wheat but I normaly get 70% for my normal wheat beer which has the same amount. I am hoping that my sample wasn't sufficiently mixed so we will see what the post boil gravity is...

My process and equipment has not changed for quite some time. I was hoping that having my own grain mill would help me stabalize my efficiency but it has not.

When I brew the same recipe, my efficiency is the same so I guess that is good...
« Last Edit: July 09, 2014, 10:14:30 AM by goschman »
On Tap:                       
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Offline AmandaK

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Re: Dramatic swings in mash efficiency
« Reply #12 on: July 09, 2014, 10:25:32 AM »
Outside of the obvious wheat thing, your volume of dead space could be different - which would lead to inconsistent measurements.

Either way, take a good look at these two articles from Braukaiser:
http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency
http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency

Both of those articles helped greatly when I had my old cooler system and when I moved to my new system.
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Offline goschman

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Re: Dramatic swings in mash efficiency
« Reply #13 on: July 09, 2014, 10:27:57 AM »
Thanks. I will take a look.

I have my kettle calibrated and use a tape measure to get my volumes. My preboil volume is always 6.23 gallons.

This recipe has a pound of rye. Similarly to thoughts about wheat, maybe the rye wasn't milled properly which partially explains my lowest efficiency to date. If I do this one again, maybe I will use flaked rye to see if there is a substantial difference...
« Last Edit: July 09, 2014, 12:34:10 PM by goschman »
On Tap:                       
American Wheat / XPA#1:Jarrylo-Zythos / Altbier / Kolsch / American Strong Ale
              
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Offline 69franx

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Re: Dramatic swings in mash efficiency
« Reply #14 on: July 09, 2014, 06:56:37 PM »
Thanks for re-posting those links Amanda. Going to have to spend some time checking them out


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