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Calculating Brewhouse Efficiency for Partial Mash

ArrogantBastardAle

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I recently made a youtube video explanation of this super awesome post on how to use BS to calculate your Brewhouse and Mash Efficiencies (http://www.beersmith.com/forum/index.php/topic,8579.0.html).  I received an interesting question from a viewer... he asked, can this be done with Partial Mashes.  Here was my response to him:

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Although I have never done a mini-mash, I believe that you can calculate your brewhouse efficiency with what Beersmith calls "Partial Mashes", or what I know you would call "Mini-Mashes".  The numbers will look a little bit strange though compared to an All Grain recipe.  You would take a pre-boil volume measurement, which would be like 2.5 gallons for a 3 gallon pot, for example.  You would also take a pre-boil gravity reading after you add all of your liquid/dry malt extract.  This gravity reading obviously would be rather high since all those sugars are concentrated.  You could then use the same method I describe in this video to figure out your brewhouse efficiency.  Note that equipment profiles are just as important here.  I believe this is how it would work, anyway.  It would be nice to get some confirmation on this.

One thing to note is that Beersmith assumes you will get 100% "efficiency" with extract.  This makes a lot of sense when you think about it. The extract is going to always give you X amount of sugars.  So, in effect you would be working with a "hidden" value which is what your mini-mash efficiency is.  Beersmith combines whatever your mini-mash efficiency is with that 100% extract "efficiency" to calculate your overall Brewhouse Efficiency. 

Also, note that what you would call "Partial Extract" Beersmith calls "Extract".  When using an "Extract" recipe in Beermsmith, the Mash Tab is unavailable and the brewhouse efficiency value does nothing.  Again, this is because Beersmith assumes all extract will give you 100% "efficiency".  If you are finding that Beersmith is under or over estimating your gravities for "Extract" recipes, you can double click the Extract and change the "Yield" or "Potential" up and down until the recipe matches up with the Original Gravity that you actually got. 
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My question to you all, am I right? 

Thanks,
Dan
 
I foresee one difficulty in taking a preboil gravity reading.  In years past, all of the extract was added in at the beginning and all of the extract was boiled for the entire boil.  Most extract or partial mash brewers now add only about a third of their extract in at the beginning.  They then boil.  This allows them to have a lower gravity boil, even when only doing a partial boil, thus increasing the efficiency of their hop additions.  It also reportedly leads to less darkening and less carmelization of the malts during the boil.

It's been shown that hop bitterness efficiency is greatly (and negatively) affected by high gravity boils.  It's also been reported that high gravity boils lead to darker than anticipated brews and carmelization.  Carmelization can be good or bad, depending on the style.  SRM can be adjusted somewhat, once a brewer is familiar with how much darkening a high gravity boil will cause. 

When I was an extract/partial mash brewer, one thing that bothered me was that my IPA's never scored well.  I now believe it was because I was doing high gravity boils (all of my malt sugars concentrated in a 2.5 gallon boil.  This made my hop additions not work very well, IMHO.

So, for those that do the late addition of extracts, they really can't take a preboil gravity reading that would have a lot of value.
 
Thanks, Scott.  I totally forgot about this technique.  I suppose one work around would be to make a copy of the recipe and include only the extract that will go in pre-boil?  Although this isn't a very clean way of doing it, this could be used to find the Brewhouse Efficiency right?  Can anyone think of a better way of doing this in BS?
 
If I wanted to know the efficiency of my partial mash, I'd probably create a seperate recipe for that part only, since I can't think of another way to do it.  I personally would use two recipes.  My main recipe wouldn't be able to accurately calculate my mash efficiency.  However, I would be able to copy that recipe and call it something like "Amber Ale-efficiency calculator".  Once I had it copied, I'd then take out the late addition extract portion of the recipe in my "Amber Ale-efficiency calculator" copy.  This would then be able to calculate my mash efficiency, because it would be able to determine what my estimated OG should be and I can measure it to see if I hit my target OG.
 
That was a few more than one, Scott!  ;)  That set of issues is a great example of the differences between extract and all grain brewing. Programs and calculations are based on all grain, full volume boils. That's going to create more than a few "square peg - round hole" scenarios.

Extract has its benefits, mostly convenience and simplicity, but the process really has to be compartmentalized based on the brewer's choices. That pretty much calls for its own set of software options, which would be pretty cumbersome and I fear, quite confusing and frustrating for a new brewer. BeerSmith skips over a lot of the consequences of extract brewing. 

My advice to an extract brewer would be not to sweat the efficiency, at all. I've always explained that for a new brewer, extract brewing is about learning the process of brewing, particularly fermentation. Other people have already made a lot of decisions for you. Things like grain choices, color, fermentability have already been determined. The recipe from a supplier or another brewer has determined an expected outcome. So, the most important thing is to learn what's "normal" in managing a boil, sanitation, fermentation and handling of a good beer.

I'm not sure there is a way to really be precise when just a few ounces of water is a high percentage of the boil volume. Plus, as Scott's hopping story suggests, with a partial boil hop prediction goes out the window. With a saturation point of 100 IBUs in the boil, a half batch boil can never exceed 50 IBU in the finished beer.

The way to look at extract brewing, IMO, is to base it on a full batch size, boil and all. Extract late and high gravity boils can then be simplified.
 
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