Kettle Shape And Boil Losses Survey - Record Your Figures Here

[Damian44]

Heres my figures

How would you describe your kettle (keggle/pot/urn/other): 80lt ally pot
How long was your boil?: 90 min
What was your pre-boil volume?:47 lts
What was your post-boil volume?: 35
What is the diameter of the body of your kettle?: 48cm
What is the diameter of the opening to your kettle? (should be same as above for pot or urn): 48cm
What is the depth of your pot/kettle?: 40cm
Do you cover your pot/kettle in any way during the boil? If so by how much and when?: No
On a scale of 1 to 10 how confident are you in your figures?: 7

 

[floppinab]

Interesting thread Pete, something thats on mind a lot given my kettle is likely to be one of the most "flat" around I think. As a result I lose on average around 35% of my pre-boil on a 75 min boil. When I first started AG with this it took me a while to understand why my gravs where 5 points or so higher than I was expecting.

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How would you describe your kettle (keggle/pot/urn/other): 100L old butchers bin
How long was your boil?: 75 min
What was your pre-boil volume?: 37.0 lts
What was your post-boil volume?: 23.0 lts
What is the diameter of the body of your kettle?: 57cm
What is the diameter of the opening to your kettle? (should be same as above for pot or urn): As above
What is the depth of your pot/kettle?: 38cm
Do you cover your pot/kettle in any way during the boil? If so by how much and when?: No
On a scale of 1 to 10 how confident are you in your figures?: 9

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I boil pretty low generally to minimize the high losses I already have.

 

[matti]

This was approximately the number I calculated my equipment to.

How would you describe your kettle (keggle/pot/urn/other): 76lt S/S pot
How long was your boil?: 90 min
What was your pre-boil volume?:33
What was your post-boil volume?:25
What is the diameter of the body of your kettle?: 43
What is the diameter of the opening to your kettle? (should be same as above for pot or urn):43
What is the depth of your pot/kettle?: 37
Do you cover your pot/kettle in any way during the boil? If so by how much and when?: No
On a scale of 1 to 10 how confident are you in your figures?: 8

I use a Rambo burner at 3/4 with a vigorous boil.

 

[PistolPatch]

Just to throw a spanner in it, I made a brew on the week-end. Pre-boil of 85L, post boil of 75L. I threw some flame out hops in waited around 15-20mins and when I measured it again I had 70L The brewery was sitting in the same place all the time. I put it down to shrinkage and evaporation. If anyone can explain otherwise.

BYB

Probably mainly just one of those measurement inaccuracies we all get from time to time no matter how well we think we measured - I hate that! With your wide pot, if you have the lid off while cooling, it is still going to evaporate a fair whack. Be interesting to see if this continues to happen to a big degree for you.

The expansion of water is exponential so this, as you reckon, could account for a few litres too. If your wort somehow dropped to 80 degrees, you would have lost about 1.2lts.

Just for interest interest and to give me practice uploading a spreadsheet, the following table shows how much 100lts of water expands between 0 and 100 degrees celsius. I've also whacked in the correction factor you need at each temperature. (I used some online calculator so it doesn't start at precisely 100 litres for some reason but you'll get the idea.)

View attachment Water_Expansion_0_to_100_degrees_Celsius.xls

Drinking is often a lot more fun than measuring

Many thanks to those like BYB who threw their figures in over the last few days.

Pat

 

[PistolPatch]

Here's a spreadsheet with your figures to date...

View attachment AHB_Evaporation_Figures_Record.xls

I have sorted them from largest surface area down and you'll see that surface area is the critical factor which is as expected.

Just for fun, I whacked in an "X Factor," with this being the volume loss per hour divided by the surface area. I then tested how well using the average X Factor is to predict volume losses based solely on surface area. You'll see the results in the last 3 columns.

It's probably as good as any other figure given to people when they are starting out and might save them the "twenty questions," game that you have to play when using an evaporation percentage figure. Also as, Screwtop says, you can pretty much expect the same volume loss in the same pot whether you are doing a single or a double batch.

Feel free to throw some more figures here if you want and I'll update the spreadsheet if this happens. (I'll have over another 5 to throw in here from other brewers by the end of next week.)

:super: for throwing in all your figures. I reckon it is always interesting to see them.

Spot,
Pat

P.S. Some figures in the spreadsheet are in brown. These are figures I had to have a guess at.

 

[crundle]

How would you describe your kettle (keggle/pot/urn/other): 40 litre Crown Urn
How long was your boil?: 90 min
What was your pre-boil volume?: 33.0 litres
What was your post-boil volume?: 25.0 litres
What is the diameter of the body of your kettle?: 340mm
What is the diameter of the opening to your kettle? (should be same as above for pot or urn): 340mm
What is the depth of your pot/kettle?: 585mm
Do you cover your pot/kettle in any way during the boil? If so by how much and when?: No
On a scale of 1 to 10 how confident are you in your figures?: 9
How would you describe your boil? (Simmer, slightly rolling, medium roll, vigorous, jumpy!): vigorous

Boiled using a 2400W over the side immersion heater instead of the thermostat controlled internal element, and the urn sides are covered with a 10mm camping mat


cheers,

Crundle

 

[pants]

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How would you describe your kettle (keggle/pot/urn/other): 98 litre Robinox pot
How long was your boil?: 1 hour
What was your pre-boil volume?: 66 litres
What was your post-boil volume?: 52 litres
What is the diameter of the body of your kettle?: 500 mm
What is the diameter of the opening to your kettle? (should be same as above for pot or urn): 500 mm
What is the depth of your pot/kettle?: 500 mm
Do you cover your pot/kettle in any way during the boil? If so by how much and when?: No
On a scale of 1 to 10 how confident are you in your figures?: 8

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[PistolPatch]

Sorry crundle and pants for taking so long to add your figures in. I'm still trying to clean up my apartment from Australia's Biggest Brew Day .

I have added your figures and those of mine for double-batches. Like Screwtop, my evaporation rate per hour in litres pretty much remains the same which means the percentage drops from 18.7% to 10.8%.

Here's the latest spreadsheet including your figures.

View attachment AHB_Evaporation_Figures_Record.xls

Thanks guys :icon_cheers:

 

[pants]

How long was your boil?: 1 hour

You've got me down for a 90 minute boil on the spreadsheet, PP.