Author Topic: Sight glass or stick  (Read 8843 times)

KernelCrush

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Sight glass or stick
« on: November 15, 2012, 05:02:14 PM »
Trying to decide if I can increase volume accuracy using a sight glass.  I have several pieces of oak that I have calibrated (wet method) by setting it on the bottom of whatever vessel I am working with, add 1 gallon water, stick the stick in against the bottom, and make a mark on the stick at the wet mark, repeat to full volume of vessel in 1 Gallon increments.  In Gordon Strong's book (and it is a really great book) he does it the opposite way (dry method)...set the stick in til it just hits the water and mark your stick based on a reference point on the vessel.  My thinking is both can be inaccurate.  Water absorbs on the stick in the wet method (and the error compounds with each addition) and the dry method you have to line up to your reference mark exactly every time.  I would guess a sight glass solves this so long as you calibrate perfectly the first time. Am I right?  Now, how do you compensate for the +/- 4% expansion of hot wort? Should you calibrate your boil kettle sight glass with boiling water? or is this expansion already factored into your anticipated post boil volume?  For my batch sizes the cool/hot 4% difference is better than 1/2 gallon. 

Offline ultravista

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Re: Sight glass or stick
« Reply #1 on: November 16, 2012, 05:37:01 PM »
I use a metal yardstick from Home Depot. It was about $7.

It works great and you can easily tell where you are based on the graduations on the stick.

Offline tom_hampton

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Re: Sight glass or stick
« Reply #2 on: November 16, 2012, 05:54:33 PM »
I use a sight glass because I can read my volume at any time without touching the wort.

Calibratebwith cold water.  Then you can always adjust hot measurements downward as needed.
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KernelCrush

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Re: Sight glass or stick
« Reply #3 on: November 17, 2012, 03:58:10 AM »
Quote
I use a metal yardstick from Home Depot. It was about $7.

How do you make permanent calibration marks?  Maybe a hammer & cold chisel.   Or do you just 'do the math' each time?

KernelCrush

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Re: Sight glass or stick
« Reply #4 on: November 17, 2012, 04:32:59 AM »
Quote
Calibrate with cold water.  Then you can always adjust hot measurements downward as needed.

I found another thread that has a similar discussion regarding mash/volume/temperature.
http://www.beersmith.com/forum/index.php/topic,7249.msg31039.html#msg31039

I assume BS2's estimated post boil volume is at 'hot' temperature, without a temperature correction.  I have been measuring my volume at about 210F.  So if I calibrate cold with either a stick or glass then I have to adjust my reading up 4%? 

Wondering if I have been doing this wrong...I measure post boil gravity at hot temps and use the hydro adjust tool to determine actual.  Since I am measuring a 4% 'inflated' volume, then my actual SG into fermentor after cooling is going to be higher?  I can check it next time I brew but my thinking is that the cooled volume decrease results in a gravity increase? 

Offline tom_hampton

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Re: Sight glass or stick
« Reply #5 on: November 17, 2012, 05:36:34 AM »
Yes, bs2 kettle volumes are 'hot'.   My experience with hydro measurement at hot temps is that they are wildly variable. I got into the habit of cooling the sample to around 100 then correcting the reading from there.  I use a refractometer now...won't ever go back.

Once I hit the kettle, I pretty much ignore bs2 volumes.   I calculate them myself based on my actual extract, target og.  I setup my brew house eff. 5% low to allow some margin.  Then I do the math based on actuals after the sparge. That way there is never any error post boil. The worst thing that happens is I leave an extra quart of wort in the kettle. 
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?

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Offline Wingeezer

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Re: Sight glass or stick
« Reply #6 on: November 17, 2012, 09:08:46 AM »
I bought an inexpensive strip of aluminum,   about 1-1/2"  wide  x 1/8" thick and about three feet long.

I calibrated one side in liters for my HLT and the other side for my BK and stamped all the markings in with a set of steel letter
punches that I had available.

I never really bothered with hot/cold etc. as I didn't really think the measurements were critical to that extent - maybe I'm wrong!

Brian

 

Offline tom_hampton

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Re: Sight glass or stick
« Reply #7 on: November 17, 2012, 09:04:29 PM »
Depends on your goal.  The difference is between 2 and 5 points of sg.  I try to hit my post-boil sg exactly. So, to me the difference matters.
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

Offline Farmbrew

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Re: Sight glass or stick
« Reply #8 on: November 18, 2012, 08:36:40 AM »
I have a sight glass for the hot liquor tank and a aluminium bar for the kettle. This was based on the reasoning that I would not have to clean up the sight-glass ex-boil.

I cal'd the aluminium so as to get the change in depth per litre then used a dremmel to put the numbers and lines on.
FV:
Conditioning: KinKan Wit
In the Bottle: Rye Saison, Aittin Rye&Juniper Ale, American Amber, Spruce Saison


Steeping:
Germination: