Accurate Volume Measurements For Crown Urn

[Dicko72]

Hi Folks,

Been my post boil gravity recently despite all volumes looking correct.
So decided it was time to recalibrate my measurements!

I use BeerSmith2 and preboil and post boil volumes are almost always bang on accoring to my sightglass scale.

Although, last brew as an example I was 2 gravity points low for preboil and 6 points low for post boil! Which doesn't make sense!

So I have a measurement issue somewhere.

I have done the following:
* Calibrated refractometer using water and ascertained wort correction factor using hydrometer
* Weighed out 5L of water in my jug
* Filled urn in 5L increments marking the sight glass
* Measured between the sightglass markings and marked 1L increments every 11mm
* Had a beer

I have also used a ruler to verify the volume in the kettle.
However I get different readings when measuring from the edge of the kettle to the edge of the concealed element ring.

I'm assuming that if my water volumes where out the gravity reading would still be linear.

Can anyone suggest areas I should focus on?

Thanks again.

D!CKO

 

[glenwal]

Can anyone suggest areas I should focus on?

Don't you just need to adjust your efficency in BS to match the pre-boil gravity readings you are getting?

If you're pre-boil gravity is off, your post boil will be off by more because you are removing (boiling off) water, but not sugar.

 

[Dicko72]

Don't you just need to adjust your efficency in BS to match the pre-boil gravity readings you are getting?

If you're pre-boil gravity is off, your post boil will be off by more because you are removing (boiling off) water, but not sugar.

I thought if my pre and post boil volumes were on target the post boil gravity would be out by the same amount as the pre boil gravity?

 

[glenwal]

Because you are removing water with the boil, but not removing sugar, you are changing the ratio of water to sugar, and hence the change in gravity will not be linear.

Try plugging your values into a calculator (try the 2nd one here and enter your volumes and pre-boil gravity)

 

[Dicko72]

Because you are removing water with the boil, but not removing sugar, you are changing the ratio of water to sugar, and hence the change in gravity will not be linear.

Try plugging your values into a calculator (try the 2nd one here and enter your volumes and pre-boil gravity)

Hmmm... may be easier than I thought to fix then...

Thanks for the link, lots of good stuff there!

 

[soundawake]

FWIW, I've got my efficiency set to 70% and boil off rate at 10% and cooling loss at 6% in brew mate for my 40L urn, an my targets have been spot on the money almost every time.

 

[BobtheBrewer]

Hi Folks,

Been my post boil gravity recently despite all volumes looking correct.
So decided it was time to recalibrate my measurements!

I use BeerSmith2 and preboil and post boil volumes are almost always bang on accoring to my sightglass scale.

Although, last brew as an example I was 2 gravity points low for preboil and 6 points low for post boil! Which doesn't make sense!

So I have a measurement issue somewhere.

I have done the following:
* Calibrated refractometer using water and ascertained wort correction factor using hydrometer
* Weighed out 5L of water in my jug
* Filled urn in 5L increments marking the sight glass
* Measured between the sightglass markings and marked 1L increments every 11mm
* Had a beer

I have also used a ruler to verify the volume in the kettle.
However I get different readings when measuring from the edge of the kettle to the edge of the concealed element ring.

I'm assuming that if my water volumes where out the gravity reading would still be linear.

Can anyone suggest areas I should focus on?

Thanks again.

D!CKO

I have a 40L Crown Urn (concealed element). I haven't calibrated the sight glass but I use the following measurements.
The first 6 ltrs = 78mm. Thereafter each 11mm = 1ltr. I use a steel rule for measurement, and always measure in the same place in the urn - it is not uniform. I use brewmate, and to calculate the required mm's of water
ltrs - 6, x by 11, + 78. This will not usually give you a round number of mm's, so I take it to the nearest whole number. When measuring the post mash/post boil/trub I use the equation mm - 78, / by 11, +6. Works for me, hope this has been some help

 

[Dicko72]

Thanks Folks. As always lots of options for me to try!