Homebrewers Association | AHA Forum

General Category => All Grain Brewing => Topic started by: goschman on January 22, 2013, 04:57:25 PM

Title: more efficiency questions...
Post by: goschman on January 22, 2013, 04:57:25 PM
Hi All. So I brewed an all munich pale ale yesterday and overshot my average efficiency by about 10 points and got my highest efficiency ever. I have a feeling it may be due getting my grain from a different shop. Their mills seem to be set to a smaller gap width since it took a lot longer to mill the grain. This aside, I have some process questions and how much they contribute to efficiency.

My mash water and sparge water volumes were almost identical. I have heard that this can increase efficiency. Any truth to this?

I batch sparge. When adding 180F sparge water the mash stabalized at 168. I try to hit 168-170 regularly but sometimes am not successful.

Any feedback would be much appreciated as I am going a bit crazy. My last batch was at about 66% efficiency while yesterday's was about 79%. It has become hard for me to predict my OGs which is really throwing a wrench in recipe design.

Title: Re: more efficiency questions...
Post by: Kaiser on January 22, 2013, 05:04:53 PM
goshman, your changing efficiency is likely caused by changed in the conversion efficiency during mashing. This efficiency is affected by mash parameters like crush, mash pH, mash thickness, time and temperature. The further you are away from 100% the more changes in these parameters can affect it and your overall efficiency. Here is some detailed reading on the subject:

http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

don't be put off by the formulae in this article. You don't have to understand them fully to understand the underlying concepts.

Kai
Title: Re: more efficiency questions...
Post by: a10t2 on January 22, 2013, 05:31:25 PM
Kai nailed down all the variables. Were the grists similar? Did you check mash pH? Crush is definitely a big factor, but I'd think the original crush would have to be truly awful in order for it to be possible to get a 20% boost in efficiency. Kai's experiments showed a maximum variation of ~10%.
Title: Re: more efficiency questions...
Post by: goschman on January 22, 2013, 05:43:10 PM
Thanks for the link...I will go through it when I have some time.

I do not measure mash pH. I think this is the one factor other than crush that may be affecting my results. Shouldn't my mash pH be somewhat consistent when using the same water and mash thickness? May be a stupid question and I assume the answer is no.

I try to keep my mash thickness consistent at about 1.4 qts/lb.

Last batch I did a 90 minute mash at 150
    50% Two row, 43.5% white wheat, 6.5% midnight wheat - 65.9% efficiency
This batch I did a 60 minute mash at 154
    100% weyermann munich I - 79.2% efficiency

The grist was nowhere similar but I usually get 66-70% efficiency regardless of the grist. I guess I will have to keep plugging away at my process and learn as much as I can.
Title: Re: more efficiency questions...
Post by: Kaiser on January 22, 2013, 06:15:28 PM
Mash pH depends on water (+salts+acids), mash thickness and the grist. For your two grist examples the 2nd grist likely leads to a lower mash pH than the first grist. Most likely that also means that it was closer to an “optimal” mash pH.

To troubleshoot your efficiency issues I strongly recommend that you start doing the mash gravity test. The idea of the test is to measure the wort gravity of we well mixed mash and compare it to the max that would be expected based on the mash thickness. you can use this table:

(http://braukaiser.com/wiki/images/3/3c/First_wort_gravity.gif)

Brewer’s Friend (http://www.brewersfriend.com/homebrew/l/50b8bd76f3156) also implemented this as one of the log entries you can create.

Kai
Title: Re: more efficiency questions...
Post by: Hokerer on January 22, 2013, 06:16:46 PM
Shouldn't my mash pH be somewhat consistent when using the same water and mash thickness? May be a stupid question and I assume the answer is no.

In addition to water and mash thickness, the types of grains will also affect the pH.  In general, roasted/darker grains will tend to drive the pH down.  So just keeping the water and mash thickness the same doesn't mean your pH will be the same.
Title: Re: more efficiency questions...
Post by: dmtaylor on January 22, 2013, 06:20:54 PM
Depending on how you calculate efficiency, your volume measurements can also have a huge impact.  For example, if you expect to make 5 gallons at an original gravity of 1.060 but you boil too hard and only ended up with 4.5 gallons, then your gravity will look way high by a ratio of 5/4.5, so you might get 1.067, which makes it look like you got like an extra 10% efficiency, when in fact your efficiency is probably the same as it always was, you just boiled it down too hard.  It can happen if you don't account for volumes in your measurements.  Think about it.
Title: Re: more efficiency questions...
Post by: goschman on January 22, 2013, 06:22:46 PM
Depending on how you calculate efficiency, your volume measurements can also have a huge impact.  For example, if you expect to make 5 gallons at an original gravity of 1.060 but you boil too hard and only ended up with 4.5 gallons, then your gravity will look way high by a ratio of 5/4.5, so you might get 1.067, which makes it look like you got like an extra 10% efficiency, when in fact your efficiency is probably the same as it always was, you just boiled it down too hard.  It can happen if you don't account for volumes in your measurements.  Think about it.

I always collect 6.5 gallons of preboil wort so I use my preboil gravity readings to measure efficency. Based on my OG into the fermenter, I calculate what my final volume was...
Title: Re: more efficiency questions...
Post by: Hokerer on January 22, 2013, 06:30:24 PM
Another strategy you might want to consider is to simply alter your efficiency targets for your big beers rather than chasing a bunch of possible tweaks/fixes.  As long as you're consistent, even it is lower, you'll be able to calculate and hit your volume/gravity targets just fine.
Title: Re: more efficiency questions...
Post by: goschman on January 22, 2013, 06:35:59 PM
Another strategy you might want to consider is to simply alter your efficiency targets for your big beers rather than chasing a bunch of possible tweaks/fixes.  As long as you're consistent, even it is lower, you'll be able to calculate and hit your volume/gravity targets just fine.

I don't do too many big beers so I am hoping to get reasonably consistent efficiencies for OGs of about 1.045-1.055. I keep a spreadsheet with charts for my efficiencies and yeast attentuation %s. Using my average efficency from about the last 20 batches, I was approximating I would hit about 1.051 with yesterday's batch...got 1.060.

Looking more and more like a mash pH issue maybe...
Title: Re: more efficiency questions...
Post by: dmtaylor on January 22, 2013, 06:54:32 PM
It could be a pH thing, but I'd look at the crush being different from different shops.  The differences in crush can have a huge impact.
Title: Re: more efficiency questions...
Post by: goschman on January 22, 2013, 07:24:11 PM
It could be a pH thing, but I'd look at the crush being different from different shops.  The differences in crush can have a huge impact.

Cool thanks. When I brew my next batch, I will go to this last place to compare my results. I am not sure how to plan my recipe design since my projected efficiency is an unknown so it will be kind of a crap shoot. I won't be able to brew too many more batches before taking a hiatus so I probably won't be able to get conclusive results.

It did take a while to mill the grains there but I now remember it wasn't necessarily because of a smaller gap. I remember the rollers turning really slow... I didn't visually notice the crush to be any different from the normal place I go to.
Title: Re: more efficiency questions...
Post by: AmandaK on January 22, 2013, 09:05:27 PM
Crush is definitely a big factor, but I'd think the original crush would have to be truly awful in order for it to be possible to get a 20% boost in efficiency. Kai's experiments showed a maximum variation of ~10%.

My crush was 'truly awful' before I tightened up my mill. I went from a range of 61%-78% to nearly consistently getting 85%.

(I thought my mill could not be adjusted because it wouldn't turn - turns out I just needed some man strength to get it to move! Had the boyfriend loosen it up for me so I could adjust it and then he cranked it down again. #womanbrewerproblems )
Title: Re: more efficiency questions...
Post by: Hokerer on January 22, 2013, 09:08:47 PM
Another strategy you might want to consider is to simply alter your efficiency targets for your big beers rather than chasing a bunch of possible tweaks/fixes.  As long as you're consistent, even it is lower, you'll be able to calculate and hit your volume/gravity targets just fine.

I don't do too many big beers so I am hoping to get reasonably consistent efficiencies for OGs of about 1.045-1.055. I keep a spreadsheet with charts for my efficiencies and yeast attentuation %s. Using my average efficency from about the last 20 batches, I was approximating I would hit about 1.051 with yesterday's batch...got 1.060.

Looking more and more like a mash pH issue maybe...

Sorry about that.  Thought I was responding to the "big beer efficiency" topic.  Wasn't meant for here.
Title: Re: more efficiency questions...
Post by: dannyjed on January 22, 2013, 09:24:33 PM
I would say it is probably the crush that would make that big of difference.  How did the grain look after crushing compared to other place?
Title: Re: more efficiency questions...
Post by: goschman on January 22, 2013, 09:52:51 PM
I would say it is probably the crush that would make that big of difference.  How did the grain look after crushing compared to other place?

Basically the same. Ground pretty fine with a lot of powder. All husks cracked.
Title: Re: more efficiency questions...
Post by: imperialstout on January 23, 2013, 03:28:07 AM
goschman, my efficiency varied too depending where I bought the crushed grain. Owner of a LHBS let me mic his mill, turned out to be .055. It prevents stuck sparges but kills efficiency.

Instead of brewing to see where your efficiency is, see if the LHBS will let you mic their mill. If you have a couple of LHBS to choose from pick the one with the smallest setting, assuming it is not too narrow to give a stuck sparge.
Title: Re: more efficiency questions...
Post by: goschman on January 23, 2013, 03:23:10 PM
goschman, my efficiency varied too depending where I bought the crushed grain. Owner of a LHBS let me mic his mill, turned out to be .055. It prevents stuck sparges but kills efficiency.

Instead of brewing to see where your efficiency is, see if the LHBS will let you mic their mill. If you have a couple of LHBS to choose from pick the one with the smallest setting, assuming it is not too narrow to give a stuck sparge.

Thanks for the idea. I guess the best solution would be to get my own mill and do it at home. I don't see this happening any time soon.

I will be getting grains from this same shop where I got higher efficicency for my next batch. I will try to remember to report back what my results are though my grist will be different. I have been too lazy to dive into pH and water chemistry so I am hoping most of my efficiency inconsisteny issues are indeed tied to the crush.
Title: Re: more efficiency questions...
Post by: Kaiser on January 23, 2013, 04:01:06 PM
I have been too lazy to dive into pH and water chemistry so I am hoping most of my efficiency inconsisteny issues are indeed tied to the crush.

Even if your efficiency is fine there is still a benefit to knowing the basics about mash pH and how it is affected by the water and the grist.

Kai