Pre boil and ending kettle volume

Tmurph6

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It appears to me in recipe editor when setting the target batch size to be ending kettle, the tool wants volumes at the following temperatures:

Pre Boil at 212F (fully expanded)
Ending kettle volume @ 68F (fully shrunk)

Example, I set my pre boil at 13.25 gal at 212, I know I boil off 1.25 gallons, then have about .5 gallons of shrink after cooling (4%). My kettle volume input into brewers friend is thus 11.5 gallons. I then know I lose about .75 gallons to chiller, trub, and miscellaneous losses resulting in 10.75 gallons into fermenter.

I choose to do kettle efficiency personally because it takes away less variables. I only care about what the gravity of the beer is in the kettle after boiling. Can anyone confirm my suspicion on what BF wants for volumes in those fields?
 
I'm about 90% sure that the recipe editor volumes, and the boil off volume, and equipment losses in user equipment profile are all referring to room temperature measurements.

I will make sure to take a look at this when I get home later tonight to confirm and go over the numbers in your post.
 
I'm about 90% sure that the recipe editor volumes, and the boil off volume, and equipment losses in user equipment profile are all referring to room temperature measurements.

I will make sure to take a look at this when I get home later tonight to confirm and go over the numbers in your post.
It actually seems like it doesn’t matter based on how the calculation works. It just takes pre boil versus kettle volume. If I put in 13.25 pre boil and say I lose 1.75 gallons between boil off and shrink it’s the same as saying 12.75 gallons with 1.25 gallons lost to boil off and 0 to shrink.

What’s puzzling is the predicted pre boil gravities are different based on pre boil volume, obviously, but according to another software program 4% shrink actually increases gravity?
 

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It actually seems like it doesn’t matter based on how the calculation works. It just takes pre boil versus kettle volume. If I put in 13.25 pre boil and say I lose 1.75 gallons between boil off and shrink it’s the same as saying 12.75 gallons with 1.25 gallons lost to boil off and 0 to shrink.

What’s puzzling is the predicted pre boil gravities are different based on pre boil volume, obviously, but according to another software program 4% shrink actually increases gravity?
We have an update that will fix the preboil gravity, which is available on the beta website, we're hoping to get it released soon.

The shrinkage should never be applied to gravity, and any efficiency calculation should be applied to cooled volumes since the hydrometer reading should always be done at room temperature and not at hot temperatures. If this is the case in other software, well they're making a mistake.

It does look like you're using the iphone app though, which is not up of date and isn't updated very frequently. We recommend using the webapp instead.

In your example, the preboil should be 13.25 at room temperature, with 1.25 gallons boiled off (at room temperature), with a postboil batch size volume of 12. The 0.5 gallons of volume lost cannot be accounted for when using target: Kettle. If instead you use target: fermenter, you'll need to decrease the efficiency to account for the 0.5 gallon lost, and set batch size to 11.5 gallons.
 

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