AHB Wiki: Balancing A Draught System

[davelovesbeer]

Just reading the post as i am trying to balance my keg system instead of pouring foam. I have 5mm line, and most people say that they use ~3m line for a 100kPa pour. I initially used the formula posted somewhere of

Length = (pressure - (height x 0.5) - 1 ) / resistance

where length/height is in feet, pressure in psi and resistance pounds/ft

Therefore for 100kPa (~14 psi), for a tap 2 ft above the keg, beer line should be about 4.5 ft, which is about what i have, which gives alot of initial foam, and is about half as long as other people are using.

How come there is such a difference between the calculation, and what everyone else uses?

 

[drsmurto]

Stupid question maybe but does the tap have to be higher than the top of the keg? What would the result be? Air in the lines? Beer foam?

 

[crozdog]

Guys,

here is a new version of the spreadsheet with info on 5mm line added. (MODS / ADMINS - can you please replace the file on the wiki with this version?)

DrS, i see no reason why you can't. If you can add a -ve number into the height cell in the spreadsheet you will get a result.

View attachment co2_and_keg_balancing_v1.1.xls

 

[andrewg1978]

I have only been kegging for about 3 batches now and have had similar issues but I am using a chiller plate through and esky on ice which in theory replaces required length of hose. I have approx 1 mt of 8mm hose b/w keg and plate and 1m of 5mm b/w plate and tap. This is hooked up to my taps sitting on an outdoor bar with esky on ground so envoironmental conditions (heat) seem to play a big part as I have been told that the beer will be warming up between the esky and tap.

Sometimes I will poor off 1/2 a pot (70% foam), let it sit for a minute to cool the tap and try again no probs. If it doesn't work, I wrap the tap in some dry ices packs and back the pressure off and seems to work well (as low as 0.3bar sometimes)! Likewise if the head is too small I have increased the pressure. This can change during the course of the keg being emptied as well.

I have tried a different type of brewkit each time and each different type of beer seems to behave differently with regards to the ideal pressure to work on my system

batch 1/ Coopers Larger - 0.3 Bar was ideal but this was on a hot night
batch 2/ Coopers Mixcana - as high as 1.7bar but the 2nd keg I have had a seal issue that I did not pick up until after gassing and could not wait to drink, so cranked up the pressure and it would go a little flat quickly but provided you slammed it down still did the job!
batch 3/ Coopers Draught - 1bar, best one so far but conditions cooler outside.

Summary - Just trial and error for me at the moment but every brew has been excellent after a little playing.

 

[crozdog]

Here is a new version of the balancing spreadsheet after CDBOWN pointed out an error in the calculation of resistance for 5/8" tubing. New version now 1.2

Thanks CD

View attachment co2_and_keg_balancing_v1.2.xls

 

[cdbrown]

Just to let everyone know that if you used the original file crozdog produced which didn't have the 5mm line size, then it worked fine. v1.1 introduced 5mm but then broke a lookup as it started to return values which excel thought were close enough instead of returning the exact value. It only affected those that used 3/8" ID, 3/8" OD, 5/16" ID and 5/16" OD as these kept providing the same line length as 3/16" ID.

Cheers
-cdbrown

 

[afromaiko]

I had a stab at adding 6mm ID tubing to this spreadsheet, but no luck. It would be great if this could be included in newer versions, because the JG tubing that Craftbrewer carries is OD 8mm / ID 6mm. Using 1/4" is close, but more accuracy would be useful. Thanks.

 

[crozdog]

I had a stab at adding 6mm ID tubing to this spreadsheet, but no luck. It would be great if this could be included in newer versions, because the JG tubing that Craftbrewer carries is OD 8mm / ID 6mm. Using 1/4" is close, but more accuracy would be useful. Thanks.

Afro,

do you have the resistance/foot (or /m) for 6mm line? Let me know & I'll add it

 

[fraser_john]

Well, after years of having different length lines and messing constantly with the regulator, I downloaded this spread sheet, went through the figures, measured the temperature in my fridge, determined what volume of CO2 I wanted to get a good balance on english ales, stout, weizen, lagers and american ales, cut all my lines to matching lenghts etc

The result.......perfect pours and carbonation!! I am wrapt and kicking myself I had not done it earlier!

AND, I only did it as I was pulling off the plastic liner from the inside of the door and replacing it with a masonite panel so I did not have to struggle to fit my fourth keg in! So as a side project, it was well worth doing!

 

[hydroboy]

I realise this is all very line dependent but the spreadsheet is using a very high line resistance for 3/16th ID tubing. 5/16th seems pretty spot on. Does any one know where I can get the line resistance figures for john guest tubing?

 

[crozdog]

I realise this is all very line dependent but the spreadsheet is using a very high line resistance for 3/16th ID tubing. 5/16th seems pretty spot on. Does any one know where I can get the line resistance figures for john guest tubing?

Try john Guest directly or a distributor like craftbrewer

 

[cdbrown]

The 3/16th stuff is in the upper range of resistance according to this website http://kegman.net/balance.html. You can adjust it yourself if you think it's too high.

 

[hydroboy]

I know you can adjust it, but the whole point of this spreadsheet is to try and get your lines right first time, or at least close to save the whole trial and error thing. Not having a go at you or the original author but is anyone using 1m of 3/16th line successfully which is roughly what the spreadsheet suggests? I have read a lot of peoples posts using 2-3m of 3/16th stuff so it seems a fair way out of the norm. I will contact john guest and get back to you.

 

[MarkBastard]

I use metric line so I've always found the spreadsheet a little hard to follow because of that.

But either way line length is the easiest factor to work out once you're sure the other factors (temperature and reg pressure) are set correctly.

 

[Logman]

I'm setting my keg system up at the moment - I bought 10m of 6mm to get me started, but after reading this article it sounds wiser to get something smaller for the lines. My taps will be about 2 feet above the middle of my keg (upright 250L fridge/freezer).

The calculations leave me thinking that I'm going to end up with pretty long lines using that diameter

If you were building a system, what size lines would you prefer?

 

[Wolfy]

The article links to a "reckoner.pdf" file, however the website (wortgames.com) appears to have gone AWOL.

Does someone have a copy of the PDF that they can upload to AHB?

 

[felten]

Theres one linked by TB here, I assume its the same thing anyway.

 

[Hedgehog]

G'day. Has anybody got a working version of the spread sheet. I get an "unknown function" message every time I try to load it up. I am trying to balance a new keg set up so any info would be appreciated.

Cheers Jim

 

[arogers]

PM your email, I'll send it to you.

PS, can anyone tell me the beer line size (as in ID) the Keg King fridges come standard with?

EDIT: scratch that, ive attached it

View attachment crozdog_balancing_table.xls

 

[Hedgehog]

Sorry Regulator, didn't read the whole message....I still cant get it to work. must be something wrong with my computer.