Beersmith boil off from Pre to post gravity

[juggabrew]

Im so flabbergasted at how beersmith comes up with the boiloff rate from pre boil to post boil gravity. I consistently only can boil off ~.006 to .007 no matter how vigorous the boil. BS predicts, depending on batch that I can go from a pre boil to post and boil off any ware from .011-.014. It’s so freaking frustrating time after time especially when I got all my numbers post mash. Today I was actually at 1.040 pre compared t the prediction of 1.035.

Can’t be possible to boil off that much gravity.

 

[Oginme]

Have you built a custom equipment profile that reflects your process and boil off rate? BeerSmith does not know what your process will lose until you tell it what your losses and efficiency is to start with.

BTW, boil off rate is a concentration of the sugars which leads to a gain in gravity reading. This is usually referenced as volume loss pre-boil to post-boil and not as a gravity increase.

 

[Smellyglove]

Have you created an eqipment profile where you've entered the evaporation rate?

 

[FunkedOut]

When you are building an equipment profile to model your brew rig, and you get to the section where you input the boil off rate, focus on volume before and after, not gravity.

 

[juggabrew]

Yes I have a custom profile. I’ve used BS for six years so it’s all set. I hit all my numbers except what’s predicted from preboil gravity to post boil gravity.

My evaporation rare is ~13%

 

[jcav]

You may have already done this but just in case you didn't, you can calibrate your boil kettle by weighing each gallon of water, which weighs 8.34 pounds for each gallon. You can put a dowel in your boil kettle and after each gallon you can pull out the dowel and mark the wet line for each gallon marking that you are interested in marking. Then you can mark your sight glass (if you have one on your kettle) exactly where the correct volume lines up on you particular kettle. This way when you collect the proper pre boil amount you can see the correct level on the now calibrated sight glass, or put the dowel in the kettle and fill until the volume line on the marker is covered by the wort. Now you know that you are collecting exactly the amount you need and can properly measure after the boil what you really are left with (either by the sight glass or sticking the dowel back in the kettle to measure). Then enter this into BeerSmith and see if this is more accurate than what you have entered now. Just trying to help you get this ironed out as I know it is frustrating. Also if you brew outside the temp and especially the humidity, will also effect boil off rate from batch to batch, if the humidity is drastically different from batch to batch.

John

 

[FunkedOut]

I just boiled off 0.011 today.
1 gallon.

1.054 to 1.065.
7.5 gal to 6.5gal.

right inline with what BS predicted.
boiloff rate in BS is 1 gallon per hour; ~13%.

If your volumes are right, maybe your gravity readings are off?
What temps are you measuring at?
Is the wort stirred up well?
Have you calibrated your hydrometer lately?

That’s all I can think of.

 

[juggabrew]

You may have already done this but just in case you didn't, you can calibrate your boil kettle by weighing each gallon of water, which weighs 8.34 pounds for each gallon. You can put a dowel in your boil kettle and after each gallon you can pull out the dowel and mark the wet line for each gallon marking that you are interested in marking. Then you can mark your sight glass (if you have one on your kettle) exactly where the correct volume lines up on you particular kettle. This way when you collect the proper pre boil amount you can see the correct level on the now calibrated sight glass, or put the dowel in the kettle and fill until the volume line on the marker is covered by the wort. Now you know that you are collecting exactly the amount you need and can properly measure after the boil what you really are left with (either by the sight glass or sticking the dowel back in the kettle to measure). Then enter this into BeerSmith and see if this is more accurate than what you have entered now. Just trying to help you get this ironed out as I know it is frustrating. Also if you brew outside the temp and especially the humidity, will also effect boil off rate from batch to batch, if the humidity is drastically different from batch to batch.

John

That’s a thought. I have an SS brewtech ktl w/ etchings on the inside, i assume those are correct but you never know.

 

[kh54s10]

Just a thought. Maybe relevant maybe not. It takes both accurate volumes and accurate gravity readings. You are going to check the volume markings. Check the accuracy of your thermometers, and hydrometer and or refractometer. If you use both make sure they agree.

Also with a hydrometer make sure the temperature is at the calibration of the hydrometer - usually 60 or 68F.

I get some variance in my OG but I cannot attribute it to the software. I'm sometimes low and sometimes high. Usually within 4 points of target most often closer so I just take what I get.

 

[jcav]

That’s a thought. I have an SS brewtech ktl w/ etchings on the inside, i assume those are correct but you never know.

I would check it to be honest. I kinda remember reading on another post that someone with the same fermenter was upset that the markings were almost a half a gallon off when he checked it.

John

 

[juggabrew]

I would check it to be honest. I kinda remember reading on another post that someone with the same fermenter was upset that the markings were almost a half a gallon off when he checked it.

John

So I went through the whole process of checking the vol. markings. Turns out it’s a 1/4 gal lower than what it should be. I had a copper pipe from my old ktl that I remarked. Kinda annoyed since part of the reason I bought a new ktl was to have the markings inside the pot so I didn’t have to mess with a measuring stick.

At least now I know that one variable has been corrected.

 

[juggabrew]

Just a thought. Maybe relevant maybe not. It takes both accurate volumes and accurate gravity readings. You are going to check the volume markings. Check the accuracy of your thermometers, and hydrometer and or refractometer. If you use both make sure they agree.

Also with a hydrometer make sure the temperature is at the calibration of the hydrometer - usually 60 or 68F.

I get some variance in my OG but I cannot attribute it to the software. I'm sometimes low and sometimes high. Usually within 4 points of target most often closer so I just take what I get.

I usually try to check them every so often. But after finding out my vol markings are off I’m definitely going to make sure those are calibrated before my next batch.

I batch sparge so I try to get it good and mixed up before pulling a sample for my refractometer. I’ve also compared with hydro in the past, usually 1 or 2 point difference.

 

[jcav]

So I went through the whole process of checking the vol. markings. Turns out it’s a 1/4 gal lower than what it should be. I had a copper pipe from my old ktl that I remarked. Kinda annoyed since part of the reason I bought a new ktl was to have the markings inside the pot so I didn’t have to mess with a measuring stick.

At least now I know that one variable has been corrected.

It's good you went through the process, now you know when the wort hits the mark on the copper pipe, you have the correct volume you are shooting for in your kettle.

John

 

[nosoup4me]

I find beersmith frustrating on a number of levels. Mostly pre boil vs post boil gravity. My problem was pretty much like yours. Id usually "go up this many pts in a 90 min boil with this much boil off". But BS always seemed to calculate for more. I think one of the problems is BS is doing a weird calc for shrinkage.

I have since set ALL my losses to zero in the equipment profile and which makes Brewhouse Efficiency = Mash Efficiency. I hate BH efficiency!!!

I know what I what volume of pre boil I need to brew for a 10.5 gallon batch with a 90 min boil (13.22 gal) & I know my boil off (1.3 gal/hr).

Then I calc loss post boil:
I know my dead space in boil kettle (0.3 gal). And I know that shrinkage is around 4%.

With all my losses (in my equipment profile set to 0) my "batch size" is actually 11.27.

13.22-(1.3*1.5)=11.27 ****1.5 is because I do 1 hr+1/2 hr boil.

Then from 11.27 (batch volume) I calculate the losses. 11.27-4%=10.81 gal - .3 gal = 10.5 gallon batch.

When setting up BS this way my est OG #'s drop significantly... BUT Always where I seem to land.

 

[chewse]

Just curious....those who are experiencing pre-boil and post-boil discrepancies, have you noticed the biggest differences with a hard boil vs a mild boil, a heavy malt load vs a light malt load or a large hop load vs a light malt load. I ask because I tweet the boil burner flame depending on the type of beer I'm making.

 

[juggabrew]

Just curious....those who are experiencing pre-boil and post-boil discrepancies, have you noticed the biggest differences with a hard boil vs a mild boil, a heavy malt load vs a light malt load or a large hop load vs a light malt load. I ask because I tweet the boil burner flame depending on the type of beer I'm making.

No, I have the same issue no matter how heavy or light the boil is. I always boil off .007 no matter what