Beer Tools' Efficiency Formula

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Beer Tools' Efficiency Formula

Postby hangtendesign » Sun Nov 09, 2008 11:07 pm

Is there any way to adjust the formula for the Efficiency calculation? When I switched over to Beer Tools from Homebrew Formulator all my old efficiency values increased exactly 6%. Also, when I enter recipes from Brew Your Own magazine the efficiency in Beer Tools is again exactly 6% more than theirs. I can't imagine that my efficiency is 89% which is what the professional brewers achieve. Could it also be possible that the Beer Tools efficiency is some other kind of efficiency value like the difference between mash efficiency and brew house efficiency?
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Postby Eeeza » Tue Nov 18, 2008 6:22 pm

Hi Hangtendesign,
I can't help you with your question, but I thought it the appropriate subject to add my query to, as it's similar in nature.
I too, am new to BTP and have just completed my first brew day with it.
I brewed a pilsner using a single step infusion @ 65C. (I'm from Australia, so we're metric over here. Bear with me).
I know I get a 76% extraction efficiency from my previous brews, but using BTP it differs because of a couple of factors. Here's the thing....
Kettle volume 28lt.
Evap rate 4lt/hr.
Boil time 1.25 hr. (5lt loss)
Final volume 23lt.
This is right. I want a 23lt batch, but...
Even locking off kettle vol and final vol, it shows a value of 0.92lt Water Added?
Also, when I transfer to the fermenter, I lose 4lt from my boil kettle, due to trub and where the tap is situated. I then top up the fermenter with 4 lt of water to make 23lt. (all noted in my adjustments)
Taking a SG reading in the kettle prior to transfer I get 53, when I top up the fermenter I get 44 which is right, but...
Under "Analysis" when I adjust the OG to 44, it increases my IBU, obviously because it reads a lower SG and therefore better utilization.
But really, the gravity for utilization purposes is 53 (actually 48 @ beginning of boil), and in fact the bitterness in the fermenter should be lower because of the added water.
I'm trying to come to terms with how I set all this out with BTP to get a constant outcome.
The water added (and lost) in "adjustments" seems to have no bearing on the outcome (SG wise).
My question to anyone clever enough to have understood my drivel is...
How do I set BTP up to allow for the loss and subsequent water additions, so that it keeps an accurate account of the process and outcome?
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Efficiency and volume

Postby slothrob » Tue Nov 18, 2008 11:08 pm

Hangtendesign, Efficiency isn't a variable equation, it's the same everywhere. The problem you're having is in the parameters for the grain you are using. You'll need to edit the grain parameters to match those used in your previous program if you want them to match. Ideally, you should get the lab measurements from the grain you're actually using to make the efficiency values accurate. North Country Malts sends this info when you buy grain from them.

Eeeza, I believe your problem is that you're not accounting for water expansion and contraction with temperature. If you measure your kettle volume at 212°F and the final volume at 68°F, the numbers will add up.
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Postby Eeeza » Wed Nov 19, 2008 4:36 pm

Thanks Slothrob,
That makes sense.
What about the 4lt water additions to account for my kettle loss.
Should I adjust my final volume to 27lt instead of 23lt so that the utilization works?
I'm trying to formulate my recipe to fit the style parameters.
When I change the OG to account for my water additions, it effects the IBU incorrectly.
What's the best way to set it out?
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volumes

Postby slothrob » Wed Nov 19, 2008 8:10 pm

I'm not sure if I'm answering your question, but...

The way I do this is to measure my volume as the pot gets close to the boil.
Measure my volume at the end of chilling (actually, I know that 5.2 gallons at the end of boil is 5 gallons at the end of the chill, due to shrinkage. So I stop the boil at 5.2 gallons).
I don't add water to make up for boil loss (I don't think very many people do), but you can enter that in the "Water volume added". The program will correct the IBU's to make up for the water addition. Don't just change the final volume, or the IBUs will be wrong. The OG should be set so that after the volume addition the OG is correct, then the IBUs will be set correctly.
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