Your Partial Mash Efficiency

I've noticed that for my last 5 or 6 partial mash batches, my efficiency has been between 80%-85% as calculated by my brewing software. This seems high to me. Just curious, for those who do partial mash, what efficiency are you getting on average?


I've gotten my system down pretty well, but my method is pretty basic. I buy milled grain. I use 1.5 quarts/pound of mash water. I hit my strike temp, place the grain bag in, adjust to get my mash temp (varies by recipe), then place into a preheated oven, stirring gently every 15 minutes or so. I do a basic batch sparge - move the grain bag from my mash pot to my boiling pot with about 2 quarts/pound of sparge water. Let that sit for 10 minutes, drain the bag, then combine my mash water with my sparge water. Typical boil with addition of extract at flameout.

i usually get around 80%, my last batch i got ~85% and overshot my gravity because i had the software set to 78%. i noticed a big jump in efficiency when i started dunk sparging (like you described doing), when i just rinse the grains, i get 70-75%, with the dunk method, it's up to 80% or higher. pretty f'n cool!

NordeastBrewer77 said:

i usually get around 80%, my last batch i got ~85% and overshot my gravity because i had the software set to 78%. i noticed a big jump in efficiency when i started dunk sparging (like you described doing), when i just rinse the grains, i get 70-75%, with the dunk method, it's up to 80% or higher. pretty f'n cool!

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Awesome! Glad to hear - I was beginning to distrust my software.

I've also overshot the OG on a few recipes recently. Oh well, they're a little bit out of style guidelines, but I won't complain about the extra ethanol!

JeffersonJ said:

I won't complain about the extra ethanol!

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right! i now have the efficiency in my software set to 80% for the next recipe. i'm also gonna start taking gravity readings of the wort before adding DME so i can adjust the DME if need be. (i know, i shoulda done that from the get go)
i really think it's the dunk sparge. i did a lot of BIAB beers sparging by pouring the sparge water over the grains after the mash, regularly got ~75%, did the dunk sparge on the last two beers and the efficiency on those is closer to ~80% or so. can't beat that with a stick!

Are you checking the preboil OG from the combined runnings to figure your efficiency? The reason I ask is that if you're not, and adding the extract and figuring efficiency, that will change.

What I mean is this- say your mash efficiency is 50%. But then you add the extract. Software figures that at 100%. So, you can see that your efficiency will "change" based on the size of your grainbill and amount of extract.

It doesn't really matter, though, until you do a bigger mash and use less extract. That's when it would really be important to know your efficiency from your mash. Does that make sense? I know what I'm trying to say, but having trouble getting it out!

Yooper said:

Are you checking the preboil OG from the combined runnings to figure your efficiency? The reason I ask is that if you're not, and adding the extract and figuring efficiency, that will change.

What I mean is this- say your mash efficiency is 50%. But then you add the extract. Software figures that at 100%. So, you can see that your efficiency will "change" based on the size of your grainbill and amount of extract.

It doesn't really matter, though, until you do a bigger mash and use less extract. That's when it would really be important to know your efficiency from your mash. Does that make sense? I know what I'm trying to say, but having trouble getting it out!

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I use Beer Tools Pro, and the efficiency variable only affects the grain bill (you actually have to back into your efficiency number using actual OG). It assumes extract is 100% efficient.

I know efficiency isn't absolutely crucial with partial mash, but I typically make my own recipes with 60% of the gravity is from grain, and 40% from extract. So, it affects me more than most mini-mash recipes where it's the opposite. (Plus, I just wanted to know what was typical!)

I just finished my first partial mash and got 65%. I used 5.876 lbs of grain, 3 lbs LME and mashed with 8.34 quarts at 149 degrees a 16-quart rectangle Coleman cooler. I lost 13 degrees when I added my grain (relying on Beer Smith 2, I was only expecting to lose 10 degrees) but then it only dropped 2 degrees during the 60 minute mash. Would like to figure out how to up my efficiency to 70%-75%.

jwalker1140 said:

I just finished my first partial mash and got 65%. I used 5.876 lbs of grain, 3 lbs LME and mashed with 8.34 quarts at 149 degrees a 16-quart rectangle Coleman cooler. I lost 13 degrees when I added my grain (relying on Beer Smith 2, I was only expecting to lose 10 degrees) but then it only dropped 2 degrees during the 60 minute mash. Would like to figure out how to up my efficiency to 70%-75%.

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What are you doing for the sparge? That's going to be what will really affect your efficiency numbers.

I basically followed DeathBrewer's easy partial mash technique and moved the grain form the cooler into 2.25 gallons of water heated to 170. I dunked it several times and let it sit covered for 10 minutes. After that, I let it drain for several minutes. Then I let it sit in a colander over a bowl to let it drain some more. I added what drained out the boil.

I should note that I didn't stir the grains while they were in the cooler because I was afraid I'd let too much heat escape.

Hm. That's my pretty much my method too and I get 80-85% efficiency. Here are a couple of thoughts:

1. Are you heating your sparge water up to 170F, then dunking the grains? Or are you maintaining the temperature of your grains at 170F? You want to do the latter. I heat my sparge up to 180F and the grains help bring the sparge water down to 170F after dunking them.
2. It might have something to do with the crush of your grains. I've heard of some LHBS having pretty poor milling processes. For the last 10 or so batches, I've gotten my grain from Austin Homebrew and have always had good efficiency. I'm sure the other big names are about equal with their milling.

JeffersonJ, thanks so much for the information. I did the former, heated to 170, turned off the heat and then dunked. I'll try your suggestion next time. And I mill at a very well-respected shop in Los Angeles so I can't imagine poor milling could be a factor.

It did occur to me that I may not be calculating my efficiency correctly. I use beersmith 2 and my recipe was set to 72% (the default) and the estimated OG was 1.054. I measured 1.051 right before I pitched yeast. Then I adjusted the efficiency setting down until the OG changed to 1.051, which was 65%.

Thanks again,
Jason

That's more or less how I calculate my efficiency too (although I don't use Beer Smith). If you want to double check those numbers, here's a neat little calculator to do so:

http://www.brewersfriend.com/brewhouse-efficiency/