Missing my OG with new BeerSmith software

[RokGoblin]

I have consistently been missing my starting gravity with the new version of BeerSmith. I would do much better at hitting, or getting very close, with the older version, but after upgrading, now I am having this problem with my last several batches.

I hit my pre-boil OG on the money, but after boiling/cooling the gravity of this last batch was 6 points low. I was expecting 1.066, but instead I got 1.060. I took 2 measurements with a hydrometer and my refractometer and both confirmed the lower gravity.

I am brewing all grain, and doing full boils with no top off water (collecting full boil volume from MLT). I stirred the wort for about 30 seconds before taking my pre-boil gravity reading to ensure I was not getting a diluted reading.

I had no wort left behind in the kettle and poured all my wort through a stainless strainer into my primary. I only collected about 5.1 gal when I was expecting 5.25 so if anything I would expect to have a higher starting OG because of the higher boil off.

This is my 36th batch and probably about 33 doing all grain, so I am fairly certain it's not process related and likely something in the new version of the software, but I could be wrong.

[alan_marks]

I have consistently been missing my starting gravity with the new version of BeerSmith. I would do much better at hitting, or getting very close, with the older version, but after upgrading, now I am having this problem with my last several batches.

I hit my pre-boil OG on the money, but after boiling/cooling the gravity of this last batch was 6 points low. I was expecting 1.066, but instead I got 1.060. I took 2 measurements with a hydrometer and my refractometer and both confirmed the lower gravity.

I am brewing all grain, and doing full boils with no top off water (collecting full boil volume from MLT). I stirred the wort for about 30 seconds before taking my pre-boil gravity reading to ensure I was not getting a diluted reading.

I had no wort left behind in the kettle and poured all my wort through a stainless strainer into my primary. I only collected about 5.1 gal when I was expecting 5.25 so if anything I would expect to have a higher starting OG because of the higher boil off.

This is my 36th batch and probably about 33 doing all grain, so I am fairly certain it's not process related and likely something in the new version of the software, but I could be wrong.

Since I have never used BeerSmith (still using ProMash), I sounds to me from your description that your boil-off percentage setting is less than what you are actually doing. Have you checked that setting?

hth,


PS -edit, I mean less than what you expect...

[RokGoblin]

Since I have never used BeerSmith (still using ProMash), I sounds to me from your description that your boil-off percentage setting is less than what you are actually doing. Have you checked that setting?

hth,

Thanks for the reply Alan, I am also wondering about boil off, but wouldn't more boil off mean less dilution and in turn a higher than expected gravity?

I didn't get the full 5.25 gal I was expecting in my primary, so my boil off %age is definaltely incorrect.

[idedek]

I have been using the new BeerSmith for several months now and haven't had any issues with missing my OG. If I'm off it's only by 1 point either way.

[spiderwrangler]

I hit my pre-boil OG on the money, but after boiling/cooling the gravity of this last batch was 6 points low.

What was your preboil volume? You said that you got less post boil volume than you expected, which would mean it was more highly concentrated, but a lower preboil volume and lower boil off rate than expected would account for this. Your gravity points (last two digits) times your volume will each other pre and post boil.

5.1 gal x 60 = 306 total points
306/(preboil OG) = preboil volume

It may also be that your stirring when taking your preboil gravity didn't mix it fully (mixed it horizontally, but not vertically?)

It could also be that there is something that is being accounted for in the settings of your software that doesn't match your system. I believe there is a setting for trub loss/deadspace that may not apply to your set up. You might check this as well.

[RokGoblin]

What was your preboil volume? You said that you got less post boil volume than you expected, which would mean it was more highly concentrated, but a lower preboil volume and lower boil off rate than expected would account for this.

Pre-boil volume was "estimated" to be between 6.5 - 6.7 gal. I need to more closely measure my kettle volume markings. The weird thing about this is I never had these issues until my last few batches (post-upgrade).

Your gravity points (last two digits) times your volume will each other pre and post boil.

5.1 gal x 60 = 306 total points
306/(preboil OG) = preboil volume

Pre-boil gravity = 1.054 (~6.6gal)
Post-boil gravity = 1.060 (~5.1gal)

I just did your calculations and this equation indicates my pre-boil volume was only 5.666 gal. No way....my turkey fryer (7.5 gal) kettle was nearly full to within an inch of the top. The 5.1 gal post-boil "estimate" is based upon the amount I ended up with in my primary bucket (using the markings from the manufacturer). I did not account for hop absorption or other absorption in that estimate, and I poured the entire volume of wort from my kettle through a stainless strainer into my primary to remove trub/hops. I think I underestimated my final volume.

Future batches shall be measured more accurately, especially after listening to the latest CYBI episode where they discussed repeatability. I usually have decent repeatability, but this time I was not so fortunate.

It may also be that your stirring when taking your preboil gravity didn't mix it fully (mixed it horizontally, but not vertically?)

I though about this, but then I didn't wan't to over analyze the problem and create more variables to worry about

It could also be that there is something that is being accounted for in the settings of your software that doesn't match your system. I believe there is a setting for trub loss/deadspace that may not apply to your set up. You might check this as well.

I was hoping that was more the case than any other variable since this is batch number 36 for me and I have never had such bad luck with my numbers until upgrading. I wonder if I should reset BeerSmith to the defaults and see where that leads.

As for the trub loss and deadspace comment, I estimated that my mash tun has ~3qts of liquid that will not drain out of it, and I estimated my BK has about 1qt of loss due to trub and hops.

Here is the output from my Beersmith Equipment Profile:

Equipment Profile: G!s Stainless Brew Pot (7.5 gal) and Cooler (48 qt)
Batch Size: 5.25 gal

Mash Tun Volume: 12.00 gal
Mash Tun Weight: 10 lbs
Mash Tun Specific Heat: 0.30
Lauter Tun Deadspace: 0.75 gal

Boil Size: 6.84 gal
Boil Time: 60 min
Evaporation Rate: 11.0 %
Calculate Boil Size: TRUE
Kettle Top Up Water: 0.00 gal
Hop Utilization Adjustment: 100.00 %

Trub/Chiller Loss: 0.50 gal
Cooling Loss: 6.00
Top Up Water into Fermenter: 0.00 gal

Created with BeerSmith 2 - http://www.beersmith.com
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[animaldoc]

Did you calibrate your bucket?

I've had buckets where the volume was spot on and some that were off by a gallon

-- Scott

Edit: I guess that would only be a valid issue if it was a new bucket starting with these "off" batches.

[spiderwrangler]

Cooling Loss: 6.00

What are the units here?