Author Topic: I keep missing my starting gravity with the new version  (Read 9653 times)

Offline rokgoblin

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I keep missing my starting gravity with the new version
« on: April 22, 2012, 08:23:51 PM »
WTF?!?!  I used to nail my starting gravity damn near every time with the old BeerSmith software version.  Now with the 2.0 version I am missing my OG by several points every time.  My most recent batch was supposed to be 1.066 and it came out 1.060.  Seriously what the hell is going on?  All batches brewed with 2.0 have come out several points below what I am expecting.

<edit> my pre-boil gravity was right on the money 1.054 but post boil is 6 points too low?  I have the correct amount of wort in my primary so what could be going on here.  I am really bummed out and might just have to switch back to the older version until I can get this sorted.
« Last Edit: April 22, 2012, 08:26:34 PM by rokgoblin »

Offline tom_hampton

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Re: I keep missing my starting gravity with the new version
« Reply #1 on: April 22, 2012, 11:15:42 PM »
Did you leave any wort behind in the kettle? 
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Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #2 on: April 23, 2012, 12:30:21 PM »
I used all my wort from the kettle and siphoned through a large stainless steel strainer into my primary bucket.  I took the gravity reading after my wort had been cooled using a hydrometer (1.060) and a brix refractometer (14.9).

I am stumped as to why the pre-boil was on target but post was 6 points short.  For what it's worth the OG is still within style guidelines, but it's not what a wanted or was expecting. 

The volume into fermenter was a bit lower than expected.  I got just barely over 5 gal...maybe 5.1 gal and was calculating for 5.25.  But shouldn't that mean my wort is more concentrated and would result in a higher OG?

I am also going to post in another forum and will post here if they reply with an answer.  I am just stumped as to what could be wrong when using the new version, or if it even has anything to do with the software calculations.  I imported all my info from the previous version when I installed and made some tweaks to

Offline glienhard

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Re: I keep missing my starting gravity with the new version
« Reply #3 on: April 23, 2012, 12:36:20 PM »
Play with the setting for boil off.  If you have any leftover printouts from the old version, compare them to the current and see if changing the boil off has the desired affect.  Also, look at the setting for your mash equipment.  Could be that something needs to be tweaked in there.

Offline glienhard

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Re: I keep missing my starting gravity with the new version
« Reply #4 on: April 23, 2012, 12:38:15 PM »
What method are you brewing; extract, partial mash or all-grain?

Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #5 on: April 23, 2012, 12:47:10 PM »
All grain....this is my 36th batch I have brewed, of which 33 have been AG batches. 

I collect my full boil volume from the MLT and use no top off water. 

The final runnings of my MLT were 8brix (1.030) and as stated in an earlier post the pre-boil gravity was 1.054 as calculated in BS.  I stirred the BK for about 30 or 40 seconds before I took my pre-boil OG measurement using the refractometer.

Offline glienhard

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Re: I keep missing my starting gravity with the new version
« Reply #6 on: April 23, 2012, 01:00:39 PM »
OK, that all sounds good, trying to double check stuff.  I'm still thinking a setting is tweaked.  Like maybe it thinks your brewhouse efficiency is higher than what it really is.  I actually had the same exact thing happen to me this weekend, oddly enough with the same numbers.  I didn't measure my mash efficiency though.  What revision of version 2 are you running?

Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #7 on: April 23, 2012, 01:02:22 PM »
v2.0.57

Offline glienhard

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Re: I keep missing my starting gravity with the new version
« Reply #8 on: April 23, 2012, 01:27:50 PM »
While it is highly recommended to run the latest release (v2.0.65), I'm not really sue it would have any affect on this issue.  I don't recall anything in the release notes about this kind of thing being worked on.  I will play with my recipe a little and see if I have any other bright ideas.

Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #9 on: April 23, 2012, 01:32:30 PM »
Thanks for the support.  I am also looking at my Brewhouse efficiency, but the older version had me at 65% which I would almost nail my gravity every time.  Version 2.x has me at 65% also.  I will update to the latest build now, but I am not brewing again for at least a week or 2...maybe more  :(

Offline tom_hampton

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Re: I keep missing my starting gravity with the new version
« Reply #10 on: April 23, 2012, 01:56:27 PM »
Can you post all your volumes (pre-boil, post-boil, into fermenter)?

I agree with Glienhard....your volumes are messed up somewhere.  Could be the boiloff setting, could be process or measurement errors, too.  Have you changed any equipment recently (site glass, boil kettle, dip-stick, fermenter bucket, etc....anything that could affect the accuracy of your volume measurements). 

If you are using different graduations on each vessle (kettle vs. fermenter) have you calibrated them to be sure 1 gallon in each equals the same 1 gallon measurement? 

Are you temperature compensating your volumes?  Hot volume will be about 4% higher than cold volume ---which would make you think you had more preboil water (and sugar) than you really do.  Finishing at 5.1 gallons cold would result in a low OG reading in the fermenter (by about 4%).

You should be able to calculate gravity points at each step.  If you didn't leave anything behind, then the gravity points for each step should add up. 

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Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #11 on: April 23, 2012, 06:03:01 PM »
Tom,

None of my equipment is new. 

I thought if my boil off was an issue my OG would be higher rather than lower, especially considering my pre-boil OG was exactly what I was expecting.

My volumes are close estimates based upon marks I dinged into my kettle.  I have yet to make a dipstick for this kettle, but I might go ahead and mark my mash paddle which I also use for stirring my kettle.

I have a 1 gallon rubbermaid container that I have measured and marked 16oz increments on.  I use that to make the final additions to my mash tun and kettle, but up to this point I have always assumed the 1 gallon bottled water jugs I use were indeed 1 gallon.  I use the marks on my BK to confirm my volumes are close to what I need. 

Sadly I recently found out my marks were a bit off on my 1 gallon container, but I have just (today) adjusted them using a reliable graduated container I got from the lab where I work.  I will check my BK in the near future to confirm my dinged marks are reasonably close.

I did not record my post boil volume on this batch, but I did estimate my pre-boil to be 6.7 gallons based on my marks, and fermenter volume to be about 5.1 gallons based on the marks on the fermenter bucket.  I have no way to know how much was lost to hop absorption, but I used 3ozs of pellet hops during the boil, so if you know how to calculate hops absorption that might help.

All of this aside, I'm not sure it's related to equipment because until I changed to the new software my gravity was almost always accurate within a point or 2.  If it ever was off, I was able to confirm that the boil off was lower than expected and I had too much wort after the boil resulting in a lower gravity.

I am not completely excluding the possibility that I am making some error somewhere, but I can't see where that might have happened so I am thinking it might be one of the many new added configuration settings in BeerSmith.

Thanks for the response and I hope I can figure this out.

G!

Offline tom_hampton

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Re: I keep missing my starting gravity with the new version
« Reply #12 on: April 23, 2012, 07:33:08 PM »
Hops absorption is around 5x dry weight.  So, 3 oz would absorb close 2 cups or so. 

I do the following arithmetic for every step in every batch:

(SG - 1)*1000 * corrected_volume = points

I do this for every running, from each batch sparge. 
Then I do this for the final wort into the boil kettle.

I add the points for each running, and compare with the final wort in the kettle.  They should match.

Then I do it for the final cooled wort while still in the boil kettle.

I compare this to the pre-boil points.  They should match.

Then I do the same thing after I transfer to the fermenter. 

The drop in points should be the same as the volume left in the kettle.

It seems like a lot of measuring...but, it allows me to detect an error right away.  Plus, with the data I can adjust my equipment profile if I learn something new about the equipment. 

If you have this data and post it here, we might be to tell where things are going wrong (either in beersmith or process).

Btw, I use one of these:  http://www.acemart.com/prod4472.html

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On Tap: Apfelwein, Kolsch(v2), Pumpkin Ale, Belgian Specialty 
Aging/Storing: Coffee Porter, Chocolate Porter, Flanders Red, English Barlywine
Fermenting: Maggie's Altbier
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Offline rokgoblin

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Re: I keep missing my starting gravity with the new version
« Reply #13 on: April 23, 2012, 08:07:09 PM »
Tom,

I unfortunately don't have all of those measurements available for this batch.  I will try to incorporate those into my next batch.

Here is what I do have:
pre-boil/kettle = 13.7 brix (1.054) - approx volume 6.7gal
post-boil/kettle = 14.9 brix (1.060) - estimated volume 5.2gal
fermenter OG = N/A - volume ~5.1gal

I am not certain on how you take gravity readings during a fly sparge.  Wouldn't you need to mix the wort to ensure you are not getting a diluted reading?  I did take a gravity reading of the final runnings using my refractometer after I collected my full boil volume and it was 8brix (1.030)

So if I fly sparge should I take pre-boil (kettle), post-boil cooled (kettle), and fermenter gravity readings.

Lucky for me I have an Ace Mart less than 5 miles away, perhaps I will go buy one of those pitchers if they have it on hand.

Offline tom_hampton

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Re: I keep missing my starting gravity with the new version
« Reply #14 on: April 23, 2012, 09:33:21 PM »
Okay, well I batch sparge.  Nevertheless....

The gravity of your initial runnings is critical in determining your conversion efficiency.  So, I would take a gravity reading after vorlauf of those initial runnings.  If you always mash with the same thickness say 1.5 gal/lb, then your initial runnings should ALWAYS have the same gravity.  Any variation is due to some error in the mash (mostly crush, but also pH, dough-balls, temperature control, etc). 

Plus, the numbers you have listed.

Looking at your data:

pre-boil = 362 pts
post-boil = 312 pts

50 pts is large.  That's over a pound of DME that "vanished" during the boil.  Nothing to do with beersmith here.  Just plain old measurement error.   Since both of these measurements are taken with the wort still in the kettle...no extract could have escaped.  Since you use a refractometer, that's pretty hard to mess up in a big way. 

Volume is easier to mess up without solid calibration.  You are looking at a 15% error...to account for the vanished sugars. If you aren't temperature compensating your hot measurments that's 4% error...leaving 11% in measurement.  That's ~1/2 gallon, which can be easy to lose.


R.I.P.:Belgian Blonde
On Tap: Apfelwein, Kolsch(v2), Pumpkin Ale, Belgian Specialty 
Aging/Storing: Coffee Porter, Chocolate Porter, Flanders Red, English Barlywine
Fermenting: Maggie's Altbier
Next Up: PtE(1.1), Belgian Dubbel?

Working thru all BCS recipes