Author Topic: Efficiency Confusion  (Read 1655 times)

Offline sbruening

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Efficiency Confusion
« on: July 21, 2014, 05:38:40 PM »
I just want to say thanks ahead of time.

So I just did my second all-grain brew last Saturday and so far turned out pretty successful, I think. However, efficiency has started to confuse me a little. I was using Brewer's Friend website to help me in the process.

The recipe was for a 3 gallon batch. With my own recipe based off a 70% efficiency.
I heated up 6 gal of water, more than needed. Used 9 qts of it for strike water and then another 12.4 qts for sparge. Got rid of the rest. 21.4 qts are now in the mash tun. Now I know I lose about 2.25 qts of water in my 10 gal cooler mash tun. I also used 6 lbs of malt. My one mistake was that I didn't check the volume that I drained out mash tun, however, the hydrometer reading was 1.041, Pre-Boil efficiency of 80%, assuming that I drained 17.2 qts. A quart more than the Brewer's Friend calculator assumed.

Here is the part I'm really confused about. Once the brew day was complete. Instead of ending up with 3 gallons, I ended up with 4 gallons in the fermenter with my actual gravity being 1.048. The expected final gravity was supposed to be 1.052. This apparently shows that I got an 86% efficiency.

Can someone please help me understand what's going on here and what I need to do the next time I brew this same recipe. All a little confusing.

Thanks a lot.

Offline morticaixavier

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Re: Efficiency Confusion
« Reply #1 on: July 21, 2014, 05:54:58 PM »
if you put 21 quarts in with 6 lb of grain and got 17.5 out you do not have 2.25 quarts deadspace.

A pound of grain will absorb about .12 gallons or ~1 pint of liquid and not let go of it. so 6*.12 = .72 gallons or close to 3 quarts that's down to 18.4 quarts. That less your deadspace should equal your pre boil.

Efficiency calcs are all suspect without really solid volume measurements. 
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Offline klickitat jim

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Re: Efficiency Confusion
« Reply #2 on: July 21, 2014, 05:55:14 PM »
I can't help. I'm one of those people who only care about brew house efficiency for recipe building,  and then only a little. I use brewer's friend too. What I do is pretty simple. I build a recipe on 70% efficiency predicted. Then I measure my fermenter OG before pitching. Then I adjust the efficiency in brewer's friend on that recipe so the predicted OG matches what I got. Depending on the beer I get between 65% on high gravity beers to 75% on beers around 5% abv. Its not precise for sure, but I only care about efficiency for recipe building. I know this doesn't answer your question. But maybe it will help to know that efficiency is not vital unless you want it to be.

Offline mattybrass

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Re: Efficiency Confusion
« Reply #3 on: July 21, 2014, 06:07:51 PM »
are you using a false bottom or a braid in your mash tun?

so if you used 9 qts for strike water thats 2.25 gallons. using a .125 gallons/lb absorption rate you would have 1.5 gallons left from your initial mash. if you sparged with 12.4 qts thats another 3.1 gallons for a total of 4.6 gallons before any loss from liquid left in your MLT.

do you know your boil off rate & how long was your boil?


Offline sbruening

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Re: Efficiency Confusion
« Reply #4 on: July 21, 2014, 06:14:18 PM »
if you put 21 quarts in with 6 lb of grain and got 17.5 out you do not have 2.25 quarts deadspace.

A pound of grain will absorb about .12 gallons or ~1 pint of liquid and not let go of it. so 6*.12 = .72 gallons or close to 3 quarts that's down to 18.4 quarts. That less your deadspace should equal your pre boil.

Efficiency calcs are all suspect without really solid volume measurements. 

I appreciate the feedback.  Like I said, that was the one mistake I feel I made when brewing this batch.  I'll probably end up brewing the same exact batch and recipe and look more closely at volumes.  I took 4 hydrometer readings throughout, which I'm starting to think is overkill.  What readings do you usually see yourself taking throughout the process?

I can't help. I'm one of those people who only care about brew house efficiency for recipe building,  and then only a little. I use brewer's friend too. What I do is pretty simple. I build a recipe on 70% efficiency predicted. Then I measure my fermenter OG before pitching. Then I adjust the efficiency in brewer's friend on that recipe so the predicted OG matches what I got. Depending on the beer I get between 65% on high gravity beers to 75% on beers around 5% abv. Its not precise for sure, but I only care about efficiency for recipe building. I know this doesn't answer your question. But maybe it will help to know that efficiency is not vital unless you want it to be.


When I first started tinkering with the notion of going all-grain, efficiency came up all the time.  However, I'm starting to lean towards your way of thinking that efficiency is good for recipe building, but how do you know what efficiency to use to begin with?  I would think it's more important that the end product stays consistent and within it's style guidelines, then making sure your getting the most out of your system.

are you using a false bottom or a braid in your mash tun?

so if you used 9 qts for strike water thats 2.25 gallons. using a .125 gallons/lb absorption rate you would have 1.5 gallons left from your initial mash. if you sparged with 12.4 qts thats another 3.1 gallons for a total of 4.6 gallons before any loss from liquid left in your MLT.

do you know your boil off rate & how long was your boil?

I boiled for exactly 60 minutes.  I don't know what my boil off rate is.  This was only my second batch with a full boil.

Offline morticaixavier

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Re: Efficiency Confusion
« Reply #5 on: July 21, 2014, 06:19:11 PM »
I generally take a pre boil reading about 2 minutes after the boil breaks. Fill a little half cup mason jar, seal it up and pop it in the freezer to chill. Then I take a post boil reading with the same strategy.

Once in a while when I'm feeling super sciency I will take a reading from the mash to attempt to determine conversion efficiency but then you need to be really really precise with your volume measurements and I'm not always.

for what it's worth, I use a refractometer for my readings so it only take a tiny bit (I take about 4 floz anyway, just for tasting purposes) when I used a hydrometer I would sometimes take a pre boil but generally only took a post boil. the benefit of the pre-boil is, if you know your volumes and you have some DME or LME or sugar around you can bump your gravity if you miss. I suppose you could water your wort if overshoot too but that's better done post boil.
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Offline sbruening

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Re: Efficiency Confusion
« Reply #6 on: July 21, 2014, 06:26:06 PM »
I generally take a pre boil reading about 2 minutes after the boil breaks. Fill a little half cup mason jar, seal it up and pop it in the freezer to chill. Then I take a post boil reading with the same strategy.

Once in a while when I'm feeling super sciency I will take a reading from the mash to attempt to determine conversion efficiency but then you need to be really really precise with your volume measurements and I'm not always.

for what it's worth, I use a refractometer for my readings so it only take a tiny bit (I take about 4 floz anyway, just for tasting purposes) when I used a hydrometer I would sometimes take a pre boil but generally only took a post boil. the benefit of the pre-boil is, if you know your volumes and you have some DME or LME or sugar around you can bump your gravity if you miss. I suppose you could water your wort if overshoot too but that's better done post boil.

Thanks a lot, I'll keep this in mind for my next batch.  Probably doing it again this weekend.

Offline klickitat jim

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Re: Efficiency Confusion
« Reply #7 on: July 21, 2014, 06:39:31 PM »


[/quote]

When I first started tinkering with the notion of going all-grain, efficiency came up all the time.  However, I'm starting to lean towards your way of thinking that efficiency is good for recipe building, but how do you know what efficiency to use to begin with?  I would think it's more important that the end product stays consistent and within it's style guidelines, then making sure your getting the most out of your system.

[/quote]

I use experience as my ballpark guess when starting a new recipe. If its a big beer I put 65% in there. Otherwise I use 70% and adjust from there. When I rebrew im usually within a couple points of my targets.

Your last sentence I agree with partially. I dont care about most out of my system. If I use a bit more grain so be it. I care about guidelines only if I send a beer to a bjcp comp, which I've done once so far. I care always about fun, enjoyment, learning, a little repeatability, etc.

Offline sbruening

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Re: Efficiency Confusion
« Reply #8 on: July 21, 2014, 07:18:12 PM »



When I first started tinkering with the notion of going all-grain, efficiency came up all the time.  However, I'm starting to lean towards your way of thinking that efficiency is good for recipe building, but how do you know what efficiency to use to begin with?  I would think it's more important that the end product stays consistent and within it's style guidelines, then making sure your getting the most out of your system.

[/quote]

I use experience as my ballpark guess when starting a new recipe. If its a big beer I put 65% in there. Otherwise I use 70% and adjust from there. When I rebrew im usually within a couple points of my targets.

Your last sentence I agree with partially. I dont care about most out of my system. If I use a bit more grain so be it. I care about guidelines only if I send a beer to a bjcp comp, which I've done once so far. I care always about fun, enjoyment, learning, a little repeatability, etc.
[/quote]

Thanks for the clarification.

Offline klickitat jim

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Re: Efficiency Confusion
« Reply #9 on: July 21, 2014, 08:38:54 PM »
You bet

Offline quattlebaum

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Re: Efficiency Confusion
« Reply #10 on: July 21, 2014, 10:38:34 PM »

Efficiency calcs are all suspect without really solid volume measurements. 
[/quote]

 What readings do you usually see yourself taking throughout the process?

For consistency reasons I always take a pre boil hydrometer reading poured into a small ss bowel in ice water that I can chill in a few min to 60F. I then can adjust my boil to insure I hit my desired FG. I take hydrometer readings at 20 min intervals and adjust as needed. Most always hit my FG. 

Offline sbruening

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Re: Efficiency Confusion
« Reply #11 on: July 21, 2014, 11:49:32 PM »
For consistency reasons I always take a pre boil hydrometer reading poured into a small ss bowel in ice water that I can chill in a few min to 60F. I then can adjust my boil to insure I hit my desired FG. I take hydrometer readings at 20 min intervals and adjust as needed. Most always hit my FG.

What kind of things do you do when you notice that your either too low or too high?

Offline Stevie

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Re: Efficiency Confusion
« Reply #12 on: July 21, 2014, 11:59:50 PM »
Three choices

1 - boil less if over
2 - boil more if under
3 - nothing

I like number three the best

Offline HoosierBrew

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Re: Efficiency Confusion
« Reply #13 on: July 22, 2014, 12:05:10 AM »

What kind of things do you do when you notice that your either too low or too high?

+1 to Steve's advice. Also :

1/ Verify that your volumes were measured correctly - mash, sparge, grain absorption, dead space, preboil, post boil.

2/ Look at your crush. This is a prime cause of low or fluctuating efficiency. If you don't have a mill, your LHBS will double crush your grain. You'll get much better, more consistent efficiency. Then buy a mill.

3/ If you've worked on these two areas and your efficiency calculates pretty consistently in the same area, then your efficiency is what it is. Then just change your efficiency in your software to the consistent value. This will help you hit your target OG in a recipe pretty accurately and consistently.



« Last Edit: July 22, 2014, 05:03:20 PM by HoosierBrew »
Jon H.

Offline sbruening

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Re: Efficiency Confusion
« Reply #14 on: July 22, 2014, 12:12:27 PM »
Thanks to everyone that has replied to this thread.  It's been pretty helpful.  Can't wait to do my third batch this weekend.  Not changing the recipe at all, just making sure I get all my volume's and measurements correct.  I'll probably be working on that for the next couple of brew sessions.

Thanks