brewhouse efficiency?
bobdrob
possible (with minimal math & science) what "efficiency" is and how to
SIMPLY calculate/estimate it? thanks, bob
John Bleichert
Brewhouse efficiency is basically your primary fermenter's specific
gravity (measured pre-fermentation) divided by the calculated maximum
value of the same.
There's some simple math involved in getting that theoretical maximum,
and the fermenter gravity is simply measured. Daniel's Designing Great
Beers is a good place to start.
Good luck!
JB
--
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The heat from below can burn your eyes out!!
Loogypicker
This really is easy to calculate if you have a hydrometer and a way to
measure wort volume. Suppose you produce five gallons of a 1.040 OG
wort. If you multiply five gallons by 40 gravity points (the number
following the decimal in the OG reading), you can determine the number
of gallon-points in the wort. In this example there are 200 gallon-
points. Although this is a strange unit, it works well.
Next, compare the gallon-points actually produced with the number
theoretically possible. Suppose you used seven pounds of malt that had
a laboratory yield of 36 gallon-points per pound. Theoretically you
could produce 252 gallon-points of extract (7 x 36). Comparing the 200
gallon-points produced with the 252 gallon-points theoretically
possible gives a brewhouse yield of 79 percent
stridex
In plain english: brewhouse efficiency indicates how well your system
extracts the fermentable sugars from the grain during the mashing
process. Due to your equipment and methods, there will be some "maximum"
efficiency you will get since it is not a perfect system.
Obviously, we want perfect (100%) efficiency. But that's impossible. So
we basically calculate it as a percentage of what fermentable sugars we
*actually* extracted to what we *could* have extracted. And so each type
of grain has a theoretical extract potential (how much we could extract
from it using a perfect system).
In purchasing our grains later, we can use the brewhouse efficiency to
determine the exact amount of grain we would need to extract the full
amount of sugars to reach a desired specific gravity for fermentation
(and thus a desired amount of alcohol in the beer after fermentation).
With respect to calculating it, suppose I have the following grain bill:
10.5# 2-row Pilsner malt (potential of 1.037 SG or 37 points)
0.5# Carapils (potential of 1.033 SG or 33 points)
My maximum extraction potential is 10.5 * 37 + 0.5 * 33 = 405 points.
Now suppose I collected 5.5 gallons in my fermenter at 1.051 SG or 51
points. My extraction is simply 5.5 * 51 = 280.5.
My efficiency is the ratio of those: 280.5 / 405 = 69.3%.
We might also want to calculate the efficiency right after collecting
(after mashing) but prior to boiling. Suppose I collected 8.55 gallons
at 1.043 SG or 43 points. My extraction is simply: 8.55 * 43 = 367.65.
And my pre-boil efficiency is, again, the ratio: 367.65 / 405 = 90.8%.
I tend to calculate my pre-boil efficiency, the efficiency of my
specified batch size, and the efficiency of what I actually collected in
the fermenter plus any additional volume left in the kettle that is not
accounted for in normal trub losses.
After doing this a few times, you might adjust your brewhouse efficiency
if you see yourself getting higher OG than you predicted. For example,
my brewhouse efficiency was 65%. After purchasing my own grain mill and
adjusting some of my brewing process, I got better efficiency (75%). So
in order not to overshoot my OG, I now use 75% as my brewhouse efficiency
which helps in calculating my future grain bills to hit a target OG.
Hope this helps.
Vladimir
news:pVntn.121631$Bs1.1...@en-nntp-01.dc1.easynews.com:
> Obviously, we want perfect (100%) efficiency. But that's impossible.
> So we basically calculate it as a percentage of what fermentable
> sugars we *actually* extracted to what we *could* have extracted. And
> so each type of grain has a theoretical extract potential (how much we
> could extract from it using a perfect system).
Excellent, well stated summary. I would just suggest that the goal is not
necessarily to get the highest efficiency possible when making beer. It's
to get the best quality wort. Potential extract is calculated under
laboratiory conditions where the grains are crushed to the consistency of
flour and then sparged until nothing but water is coming out of the grain
bed. To achieve 100% efficiency in a brewery setting with conventional
lautering systems would result in a poor quality, oversparged wort (tannic,
astringent, etc.).
-Vlad
Joel
>I would just suggest that the goal is not
>necessarily to get the highest efficiency possible when making beer. It's
>to get the best quality wort.
>To achieve 100% efficiency in a brewery setting with conventional
>lautering systems would result in a poor quality, oversparged wort (tannic,
>astringent, etc.).
Excellent point. Many years ago there was a guy around these
parts who bragged about his great efficiency, to the point of
stating that anyone who had lower efficiencies was doing
something wrong. The thing is, he was fairly well known for
making tannic, astringent beer!
--
Joel Plutchak
"New opinions are always suspected, and usually opposed, without any
other reason but because they are not already common." - John Locke
bobdrob
"Joel" <plut...@see.headers> wrote in message
news:hp58pk$t6e$1...@barley.ncsa.uiuc.edu...
thanks to all for un-addling my pate!
barn...@ureach.com
all? I wouldn't mind using a few extra pounds of malt, if it made
superior beer. I usually get around 75% efficiency.
Roger
stridex
Agreed. I actually believe that consistent efficiency is what to look
for. Perhaps the best that can be done with your equipment is 65%
efficiency. If you hit that every time, then I think you have no
problem. Of course, we're always trying to better our systems. This
hobby is neverending in that regard.
The Davenport's
The best way to make beer is to hit the same efficiency every time. If you
can consistantly hit 65%, just up the grain bill and call it a day. At 75%,
I'd actually think about backing off a little...as a general rule, I've
found that right around 70% seems to be the sweet spot for most.
Your mileage may vary
Mike