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Boil Volumes

GR22

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When BS estimates pre-boil volume, does the reported figure account for volume change due to increased temperature?  Likewise, when I measure pre and post boil volume, should I record the actual volumes or should I correct for the higher temperatures?  I measure my mash water addition volumes at room temperature, but of course what comes out of the mash tun is hotter and post boil is significantly hotter.
Thanks
 
I personally have never adjusted volumes for temperature.  I just record the volume at the time of measurement.  I'll be interested if anyone thinks it makes much difference.
 
I always record my actual measurements and the temperature that those measurements are taken at.  Then I convert the measurements to STP conditions.  If something doesn't make sense later, I have the original raw data to review, and see if perhaps I converted in the wrong direction or something. 

Does it make a difference?  Yes.  SG is always converted to STP conditions by your hydrometer conversion chart, or ATC refractometer.  If you don't convert your volume to the same conditions...you begin to pass the error through the process. 

How big? It depends.  It's at least 4%.  But, it can be bigger (multiples of 4%) if you propagate the error from one calculation to the next.  Any multiplication/division involving two volumes with this error will "double" the total error.  4% isnt much of a big deal in beer making, but 8% or 12% can be. 

If you just record data, and don't manipulate the process to correct for measured variations it won't matter much.  As you know, I DO control the process.  Therefore, I'm careful to ensure that I don't introduce additional error.
 
I believe post boil volume is the volume at or near boiling.  If you look at the volumes tab Beersmith deducts the 4% for shrinkage (and other losses) to arrive at your volume to fermenter.  It doesn't appear to account for temperature elsewhere and I'm not proposing it should, but as your batch size increases is this 4% a constant?  I have found that number hard to measure cause don't you have other losses in the kettle, like whole hop water absorption, then the cold break in the fermenter?
 
If you are asking me:

Q1: Ideally, no.  In practice?  I have no idea.  I wouldn't expect that to matter over small integer multiples until you started measuring in multiple barrels...if at all.

Q2:  i have a sight glass on my kettle so I can measure it quite easily and precisely.  Shut off the flame, record the sight-glass reading.  Cool using immersion chiller, record second sigh-glass reading.  4% is pretty much dead on.  If you use a plate or counterflow chiller...I can see why it would be impossible to measure. 
 
GR22 said:
When BS estimates pre-boil volume, does the reported figure account for volume change due to increased temperature? 

Yes. The volume follows what you have in your equipment profile. Preboil is measured hot at the expansion rate that you input.

Likewise, when I measure pre and post boil volume, should I record the actual volumes or should I correct for the higher temperatures? 

If you are comparing your numbers to BeerSmith, then actuals is the way to go. Pre and Post volume numbers include thermal expansion.

Here's the tricky part: Batch Volume as seen in the Fermentation tab is measured chilled. So is the Loss to Trub and Chiller. This tab does not include the post volume boil number, but the Brew Steps report has both.

I measure my mash water addition volumes at room temperature, but of course what comes out of the mash tun is hotter and post boil is significantly hotter.

Measuring volumes cold and then heating is fine. Thermal expansion is not an increase in actual volume, other than it can over top the physical size of your container. This is because the weight of the water doesn't change with temperature. The expansion between 70F (21C) and 170F (76C) is 3%, which represents the steepest part of the curve.

For kettle accuracy, I've created a dipstick for volumes based on 200F (93C). It's within a half percent of 175F (80C) and 212F (100C), on either side.
 
I use the temp expansion (4 %) for my post boil volume, but set the expansion value to zero (0%) to figure out my pre-boil volume.  I also know my boil off, trub loss, and the volume I want into the fermenter.  In doing so, I have been able to accurately create a set of measuring sticks that I use to fill my kettle when sparging, and to also check that I have boiled down to the level I want prior to cooling and moving to a fermenter.

The way that I figure it is that if I can keep my volumes consistent, I can then play with my efficiencies to get my SG and OG correct.

I've only done a handful of all grain batches, but I'm tuning in my equipment...and realize that it is a process that takes some time and experimentation.  So far, I have undershot, overshot, and have hit the mark of my OG.  All with keeping my volumes consistent.

Oh, and a Happy New Years to everyone!!

-Dan
 
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