Partial Mash Efficiency

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realestatecat

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I've read the wiki on efficiency and I think I understand it from the All Grain point of view, but how about for partial grain brewers like myself? :confused:

How is efficiency calculated when you are using LME or DME and just a pound or two of grains or specialty grains?

Is it even worth trying to calculate?

If it's important, could someone tell me how to calculate efficiency with Partial Grain/Extract brewing?

Thanks
 
Calculating efficiency for a partial grain batch really has no importance at all... Unless you are dying to know, I wouldn't bother. When using malt extracts (DME or LME) in appropriate quantities, you are basically guaranteeing that your batch will have plenty of fermentable sugars for the yeast to react with. Even when brewing partial grain batches, the grains are almost always "specialty grains" meaning that their primary purpose is flavor, color, etc. and not so much starch conversion... When all grain brewers rant about efficiency, it really comes down to the fact that if you have a poor enough efficiency, your beer will not properly ferment, if at all. Hope that helps.
 
To answer your question, you measure and calculate efficiency exacly the same way for PM as AG except you only need to focus on the proboil wort that is derived from the mash/lauter. THe reason is, when you add the extract, it artificially skews the results because extract is always 100% efficient.

After you mash and lauter and first put it into your boil pot, you need to stir it up to combine the runoffs. Then take an OG reading and make sure to note the exact volume you have in the pot. These two figures will be the input to efficiency calculations as well as the exact grain bill used.

I would argue that PM recipes that expect a good portion of the OG to come from the mash would benefit from practices that maximize efficiency (and regularly checking on it). If all you're mashing is a pound each of 2-row and flaked oats, it really won't matter.
 
I do partial mashes, and I care about measuring my efficiency. I typically get about half my fermentables from the mash and the other half from extract, so a difference in mash efficiency can have a significant impact on the final brew.

The easiest way I found to measure this is using Beer Smith. Enter your recipe, including both grains and extract, and look at what OG it predicts, then tweak the efficiency setting to make the OG prediction match what you actually measured. This way you can do everything from a single gravity reading at the same time as you pitch the yeast, and the software will take the extract contribution into account for you.

Make sure you stir really well before taking the reading, though! The first couple of times I tried this, I took my gravity reading before I shook the carboy to aerate it, and got crazy results because the wort wasn't properly mixed with the topup water. One time I had like 30% efficiency, the next 95% :)
 
It's good to know if you're expecting to get a significant amount of your fermentable sugars from the mash. I like to do decent sized partial mashes - my 2 gallon drink cooler can handle up to 5 lbs or so. I'd been wanting to try a 2.5 gallon AG batch for the lonely Mr. Beer fermenter anyway, and thought it would also be a good opportunity to see if I was getting the efficiency I thought I was with my technique and setup. The brew actually went pretty smooth, I made it exactly the same way I conduct a partial and got 67% efficiency according to beercalculus.
 
Extract brewing - not a consideration
Partial mash works exactly the same way as for AG.
 
I think it's important to keep track of your efficiency on partial and full mashes. I've been doing it for a long time with different setups and it is key to figuring out how I am doing with my procedures.

As far as your original question: I have beersmith and have become lazy. I'd do what bobby said. :)
 
I do partial mashes, and I care about measuring my efficiency. I typically get about half my fermentables from the mash and the other half from extract, so a difference in mash efficiency can have a significant impact on the final brew.

The easiest way I found to measure this is using Beer Smith. Enter your recipe, including both grains and extract, and look at what OG it predicts, then tweak the efficiency setting to make the OG prediction match what you actually measured. This way you can do everything from a single gravity reading at the same time as you pitch the yeast, and the software will take the extract contribution into account for you.

Make sure you stir really well before taking the reading, though! The first couple of times I tried this, I took my gravity reading before I shook the carboy to aerate it, and got crazy results because the wort wasn't properly mixed with the topup water. One time I had like 30% efficiency, the next 95% :)

This is a good point because I know that at least Beertoolspro accounts for the fact that efficiency only applies to the mashed portion of the bill. There may be some software that doesn't get it right and certainly you could mess it up if you calculate it out by hand.
 

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