Mash Efficiency vs Brewhouse Efficiency

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So, I completed my 2nd AG brew a few weeks ago, and it was the first that I had taken enough measurements to calculate mash and brewhouse efficiencies. I was a bit surprised by the result. Beersmith tells me that my mash efficiency was about 83%, but my overall brewhouse efficiency dropped to 68%. I'm happy with the mash efficiency, but I am surprised that I lost so much efficiency during the boil, and everything I've read so far only gives tips on increasing mash efficiency. Any idea on what I could have done wrong to lose so much efficiency during the boil? What I can change to keep the efficiencies in line?

Preboil gravity was 1.034, rising to 1.038 after a 90 minute boil. I had 7.5 gallons going into the boil, put 5.5 gallons into the fermenter and had about 0.5 gallon lost to trub \ left after hitting 5.5 gallon.

Thanks!!
 
Preboil gravity was 1.034, rising to 1.038 after a 90 minute boil. I had 7.5 gallons going into the boil, put 5.5 gallons into the fermenter and had about 0.5 gallon lost to trub \ left after hitting 5.5 gallon.

Thanks!!

Something doesn't add up there.

If you had 7.5 gallons of 1.034 wort at the start of the boil and you finished with 6 gallons of wort (5.5 in fermenter and 0.5 still in kettle), the gravity of that 6 gallons of wort should have been 1.043, not 1.038.
 
I suppose then this could be a misreading of one of the gravity measurements then? Might be a dumb question, but should the pre and post boil gravity readings be inversely proportional to the volumes?
 
I suppose then this could be a misreading of one of the gravity measurements then? Might be a dumb question, but should the pre and post boil gravity readings be inversely proportional to the volumes?

yes, it's a direct relationship since you are only removing water when you boil and not sugar.

Volume_A * Gravity_A = Volume_B * Gravity_B

As volume decreases, gravity increases.
 
Got it, thank you!

I'll chalk it up to a bad reading this time. If that proportion holds up in the readings, then the mash & brewhouse efficiencies are pretty much always going to be close to one another, right?
 
f that proportion holds up in the readings, then the mash & brewhouse efficiencies are pretty much always going to be close to one another, right?

Well..... no, not really. The "brewhouse" efficiency should not "count" the stuff you left behind in your kettle or anything. It's just a "I got this much wort at this gravity in my fermenter... period."

So, let's say I make some beer and I have 7 gallons of wort in my kettle at the start of the boil with a gravity of 1.040, and let's say that this was with 75% efficiency.

I boil this for a while, chill, and run it into my fermenter and end up with 5 gallons at 1.050. What is my brewhouse efficiency?

Proportions math now.

if 7 gallons of 40 weight wort is 75 percent, then 5 gallons of 50 weight wort is What percent?

(7*40)/75 = (5*50)/X

X = (5*50*75)/(7*40) = 67

SO, mash efficiency was 75%, but brewhouse efficiency is 67% because you lost a half gallon of wort after you boiled and chilled it.
 
*noob question*

What IS "efficiency" exactly?

What's it's purpose? To me, it just seems like watered down beer.

For example, my current batch yielded me about 53% efficiency, but a 1.060 post-boil OG. Had I upped my efficiency to the level it is supposed to be, (i.e. larger volume of sparge water), I'd most likely be starting with a 1.030 or lower OG, which wouldn't make for a good big beer, IMO.

Am I just completely confused, or is it impossible to have high efficiency with a big beer?
 
*noob question*

What IS "efficiency" exactly?
A measure of how much of the sugar you are able to extract from your grain.

What's it's purpose? To me, it just seems like watered down beer.
It's purpose is to let you know how much "mileage" you are getting so that when you formulate a recipe, you know how much grain to use to obtain a certain gravity level.

For example, my current batch yielded me about 53% efficiency, but a 1.060 post-boil OG. Had I upped my efficiency to the level it is supposed to be, (i.e. larger volume of sparge water), I'd most likely be starting with a 1.030 or lower OG, which wouldn't make for a good big beer, IMO.

No.. if you up your efficiency, then you end up with a higher OG at the end of the day, because upping yor efficiency means you managed to get more sugar out of the grain.

Am I just completely confused, or is it impossible to have high efficiency with a big beer?

I do think you are a bit confused, but ... no.. it's not impossible to have high efficiency with a big beer.
 
Ahh, well maybe I was using an erroneous efficiency calculator then. It basically seemed like as the efficiency went up, the gravity went down, as the wort was basically getting "watered down".

For example...at 5gal of collected runnings, I was at 53%, but if I sparged an additional 4galls, it would bring me up to 85% or so. But it seems to me like the more one sparges, the more diluted the wort will be, as you are ultimately using the same amount of grain. Maybe that is where I am mistaken.
 
i'm in the same situation. i have great mash efficiency but what i end up with in the fermentor is much lower. i always end up topping off with water, and i think i've been leaving too much being in the kettle.
 
Ahh, well maybe I was using an erroneous efficiency calculator then. It basically seemed like as the efficiency went up, the gravity went down, as the wort was basically getting "watered down".

For example...at 5gal of collected runnings, I was at 53%, but if I sparged an additional 4galls, it would bring me up to 85% or so. But it seems to me like the more one sparges, the more diluted the wort will be. Maybe that is where I am mistaken.

Yes, the more you sparge, the more diluted the wort is, but you also have more of it. Then you boil it down to some smaller final volume. That final volume you are shooting for is the same regardless of whether you sparged a little or a lot.

When you boil it down, you are concentrating the sugars. Even though you started off with more wort that was more diluted, you end up with the same amount of wort that is more concentrated.

Did that make sense?
 
Yes, the more you sparge, the more diluted the wort is, but you also have more of it. Then you boil it down to some smaller final volume. That final volume you are shooting for is the same regardless of whether you sparged a little or a lot.

When you boil it down, you are concentrating the sugars. Even though you started off with more wort that was more diluted, you end up with the same amount of wort that is more concentrated.

Did that make sense?

Ahh I see now. Because the thinner the wort (in terms of more water = thinner) the more water that will boil off. Interesting.
 
i'm in the same situation. i have great mash efficiency but what i end up with in the fermentor is much lower. i always end up topping off with water, and i think i've been leaving too much being in the kettle.

Yeah, the amount you leave behind in the kettle can really screw you if it's a lot.

Say you made 5 gallons (5 in the kettle at the end of the boil) but only manage to get 4.5 into the fermenter. You just lost 10% of your wort, which is significant.

If you then add that 10% back as water, you just diluted everything quite a bit.

I went through a process of taking measurements on all of my gear when I started brewing all grain. I know how much dead-space there is in my kettle, as well as how much wort my hops will absorb. So, when I make a batch of beer, I make a batch that is larger that 5 gallons to compensate for these things.

The end result is that I often brew 5.25 to 5.50 gallons, and end up with 5 in the fermenter.

If I didn't compensate, I would have to just deal with 4.50 to 4.75 in the fermenter.
 
yeah, this was especially evident yesterday when i brewed a ipa using 10oz of semi-wet hops in the kettle. probably soaked up a gallon of wort :(

i think the root of my problems is i only have a 7g kettle, and wisconsin winters are pretty dry so i boil off a ton.
 
i think the root of my problems is i only have a 7g kettle, and wisconsin winters are pretty dry so i boil off a ton.

If your volume in the fermenter is low due to excessive boil off, then adding water is perfectly fine to do. Your wort will have less volume and a higher gravity than it should have had, so water will bring it back into alignment.

If your volume in the fermenter is low due to dead space in the kettle or hop absorption, then adding water will dilute it.
 
i don't think the boil-off is too excessive, but i can't sparge enough because i can only fit 6.5gal in the kettle.
 
I'm going to refresh this subject.

So you can easily increase the "brewhouse efficiency" by simply starting with more pre-boil volume and then boil longer / or more vigorously to get your target after-boil volume? You will end up with more sugars after-boil and therefore higher "brewhouse efficiency".

In other words, two brewers could have the same "mash efficiency", but if one of them starts with higher pre-boil volume, but ends with the same after-boil, his "brewhouse efficiency" is going to be much higher?
 
No, brewhouse efficiency is independent of pre-boil volume. If two brewers end up with the same amount of wort with the same gravity in their fermenters, their efficiencies are the same regardless of how they got there. The once with the lower pre-boil volume just did it in less time and used less propane/electricity/etc.
 
I understand that, but if two brewers end up with the same OG and the same after-boil volume, they both have the same Brewhouse Efficiency, but the one with higher pre-boil volume has a lower Mash Efficiency?
 
Mash efficiency is calculated as volume times measured gravity divided by volume times the theoretical gravity that would be present if all the sugar was extracted from the grain. Thus, the person with the higher pre-boil volume would have a lower pre-boil gravity. Assuming they both lose the same amount of wort to trub, their mash efficiencies would have to be the same for them to get the same final volumes and gravities.
 
Got this from Brewer's Friend, home brewing resources

"Brew house efficiency is the calculation of the overall efficiency of your brewing system. It takes into consideration the percent of potential grain sugars that are converted in the mash, effectively washed during the latuer and all wort losses in your system. If you do not accurately calculate the brew house efficiency of your brewing system you will find it very difficult, of not impossible, to anticipate the OG of the recipes that you are brewing. Here are some helpful equations to calculate efficiency in your brewing system: The following equations assume 10 pounds of 2-row pale malt in 5 gallons of water, with a mash/lauter efficiency of 75%.

Calculating Extract Potential:

((grain points)*(pounds of grain)) / (volume in gallons) = extract potential
((36)*(10)) / 5 = 72 or 1.072

Calculating recipe OG:

(potential points) * (brew house eff.) = OG
(72) * .(75) 75% = 54 or 1.054

Calculating Efficiency:

(measured points) / (potential points) = efficiency
(54 or 1.054) / (72 or 1.072) = 75%

Calculating Brew house Efficiency:

(Measured Points * Actual volume) / (Potential Points * Target Volume) = Brew house Efficiency
((54) * (4.5 gallons)) / ((72) * (5.0 gallons)) = 67.5%"

And here's a good explanation also: http://www.beersmith.com/blog/2008/10/26/brewhouse-efficiency-for-all-grain-beer-brewing/
 
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