Kegging Pressure

[Dark Maiden]

Hey All,

Kegged my first beer the other day, and after letting it settle from forced carbonation I had to set at 5psi for serving. This seemed pretty low based on stuff I have read.

Would the cause of this be that the tubing is too short? Or could it be it's too hard?

I did have some problems with this tubing cracking around the barbs, so have had to shorten the gas portions a little bit, however the beer lines have stayed the full length supplied.

I am assuming serving at lower PSI is not really an issue, just after some education on the cause.

Cheers All

 

[MHB]

You might want to clarify what the Question is, what problem are you having that you need to solve?

Try phrasing it in kPa or Bar, all the maths works better in metric.
Tube cracking around barbs usually means the line is too small or cheap crap material. You can stretch 5mm line onto a 6mm barb, (a 4mm one wont last long - stretched too thin) Heat the line until it looks transparent (well less opaque) only heat the length of the barb plus a couple of mm. Push the line onto the barb, carefully pour boiling water over the junction, (I use the steam wand on the coffee maker same/same) the line will try to return to its original size shrinking up as much as it can, this will also relieve a lot of the stress in the plastic - makes the time to fail a lot longer.
On the gas side it doesn't matter how big or long the lines are (within a very large margin) the pressure will equalise pretty quickly. If you are having problems with line splitting (that will cost you a bottle of gas) try better quality line and try 6mm rather than thinner, it wont be as stressed and will last longer (decades).

Try to think in kPa rather than PSI, there is a pressure temperature equilibrium that is perfect for most beers, this is expressed in g/L of dissolved CO2 (Americans use Volumes), at any given pressure and temperature you will get a specific amount of dissolved CO2 (fizz).
At the same temperature more pressure will increase the dissolved CO2
At the same pressure lower temperatures will increase the dissolved CO2
You need to decide how much dissolved CO2 you want for the beer you have made, this gives you the target g/L
Measure the temperature of the beer.
Set your regulator to give that amount of dissolved CO2
Wait for it to all equilibrate.

Have a read of this Braukaiser Carbonation Tables.
At the foot of the table

Beer like Tooheys New, Carlton Draught and XXXX are going to be somewhere in the 4.5-5g/L range


Then comes the line length to the tap, the longer it is the slower the flow, if it was short the beer might be coming out fast enough to do a U turn in the bottom of the glass had hit you in the eye.
A longer thinner line impedes flow, trick being to work out how much line to use. There are calculators on line but you need to pin down an operating pressure first.
Mark

 

[Dark Maiden]

You might want to clarify what the Question is, what problem are you having that you need to solve?

Try phrasing it in kPa or Bar, all the maths works better in metric.
Tube cracking around barbs usually means the line is too small or cheap crap material. You can stretch 5mm line onto a 6mm barb, (a 4mm one wont last long - stretched too thin) Heat the line until it looks transparent (well less opaque) only heat the length of the barb plus a couple of mm. Push the line onto the barb, carefully pour boiling water over the junction, (I use the steam wand on the coffee maker same/same) the line will try to return to its original size shrinking up as much as it can, this will also relieve a lot of the stress in the plastic - makes the time to fail a lot longer.
On the gas side it doesn't matter how big or long the lines are (within a very large margin) the pressure will equalise pretty quickly. If you are having problems with line splitting (that will cost you a bottle of gas) try better quality line and try 6mm rather than thinner, it wont be as stressed and will last longer (decades).

Try to think in kPa rather than PSI, there is a pressure temperature equilibrium that is perfect for most beers, this is expressed in g/L of dissolved CO2 (Americans use Volumes), at any given pressure and temperature you will get a specific amount of dissolved CO2 (fizz).
At the same temperature more pressure will increase the dissolved CO2
At the same pressure lower temperatures will increase the dissolved CO2
You need to decide how much dissolved CO2 you want for the beer you have made, this gives you the target g/L
Measure the temperature of the beer.
Set your regulator to give that amount of dissolved CO2
Wait for it to all equilibrate.

Have a read of this Braukaiser Carbonation Tables.
At the foot of the table
View attachment 112630
Beer like Tooheys New, Carlton Draught and XXXX are going to be somewhere in the 4.5-5g/L range


Then comes the line length to the tap, the longer it is the slower the flow, if it was short the beer might be coming out fast enough to do a U turn in the bottom of the glass had hit you in the eye.
A longer thinner line impedes flow, trick being to work out how much line to use. There are calculators on line but you need to pin down an operating pressure first.
Mark

Wow that is a hell of a response. Thanks for that. I am very new to the kegging department, so will have a look at all of that in detail.

Appreciate the response and all the info.

 

[Hpal]

I use the 5mm tubing like this, not the vinyl stuff you can get from bunnings.
For my particular set-up I use about 2.5m of 5mm tubing for the beer line and run anything between 12 and 15psi on the co2 depending on the beer. Fridge temp about 3 or so degrees. This is just what has worked for me every time. Heat the end of the hose in hot water and push onto your barb, no clamp necessary and no splitting.

 

[MHB]

Why PSI, FFS work in metric
Other than that, it looks like good commercial beer line, I cant tell if is solid or dual layer, the dual layer one is the better of the two.
Mark

 

[Hpal]

PSI is the only imperial measurement I like. Much easier to get your head around than 0.82 bar, metric may work better for calcs but psi works well for everyday use. Same way if you told someone a baby was born at 8 lbs, they'd know instantly whether that was light, heavy or just right, tell them it's 3.6kg and they couldn't translate it to what they know as normal.
Metric for everything else though, the less like America we are the better.

 

[brewgasm]

5 psi sounds very low. My system runs at 10-12 psi beer lines are 4mm ID and are 2 meters long. Beer temp in the keg is usually 2°-3°c but I need to check that because I have changed fridge from summer to winter to stop the beer from freezing.

It is funny that when I look at pressure guages I only see pounds, but I guess I'll be paying attention to the metric units soon enough.

I don't know what carbonation levels my beers have I just know that I like it. I want to work out what the co2 saturation is because I want to experient with higher carbonation. It only takes me 10 seconds to swap out a beer line so I think that I am going to try a 3m line to see what happens. I have about 15m of 4mm ID so why not.

 

[Yuz]

Re - metric, totally agree, my brew log and all measurements are in kg & kPa, I prefer it this way.
Although PSI seems to be a commonly understood UoM... But, try looking up "BIAB water to gran ratio" - f. me, what is 1lb to 2.5qt? 0.45kg to 2.37 litres (NOT liters)?
/// vented out

 

[brewgasm]

And what is the go with imperial units on grain bills /beer recipes and what the °F does it even mean lol

 

[Bonenose]

Buy some good line if you haven’t already. When I started kegging I inherited some line from somewhere and had nothing but trouble. Had to buy some more for an upgrade and ended up with way better quality stuff have since thrown out all the other crap, so much nicer and easier to use.

 

[MHB]

5 psi sounds very low. My system runs at 10-12 psi beer lines are 4mm ID and are 2 meters long. Beer temp in the keg is usually 2°-3°c but I need to check that because I have changed fridge from summer to winter to stop the beer from freezing.

It is funny that when I look at pressure guages I only see pounds, but I guess I'll be paying attention to the metric units soon enough.

I don't know what carbonation levels my beers have I just know that I like it. I want to work out what the co2 saturation is because I want to experient with higher carbonation. It only takes me 10 seconds to swap out a beer line so I think that I am going to try a 3m line to see what happens. I have about 15m of 4mm ID so why not.

If you convert that stupid 10-12 PSI to kPa (70-80kPa) and your temperature 2-3oC and have a look at the table in Braukaiser
At 80kPa and 2oC you have 5.3g/L (Max, Highest pressure lowest temperature)
At 70kpa and 3oC you have 4.6g/L (Min Lowest Pressure and Highest Temperature)
Pretty much across the Lager Range.
He gives the Equation that generates the table, its pretty easy to put together a spreadsheet that lets you do the calculation for any specific set of conditions. Also nice to be able to use goal seek to tell you what pressure you need to get a specific level of carbonation.
Bare in mind Gauges on regulators are rarely all that accurate, you can get digital and precision gauges but never seen a "cheap" precision gauge. The temperature in a fridge can vary a lot (up to 5oC) top to bottom, a small fan will keep it homogeneous. I have seen the carbonation change a lot between the start and finish of the keg, play with the numbers above but at the same pressure if the top of the keg is 3oC warmer than the bottom the amount of dissolved will change accordingly.
Mark

 

[brewgasm]

If you convert that stupid 10-12 PSI to kPa (70-80kPa) and your temperature 2-3oC and have a look at the table in Braukaiser
At 80kPa and 2oC you have 5.3g/L (Max, Highest pressure lowest temperature)
At 70kpa and 3oC you have 4.6g/L (Min Lowest Pressure and Highest Temperature)
Pretty much across the Lager Range.
He gives the Equation that generates the table, its pretty easy to put together a spreadsheet that lets you do the calculation for any specific set of conditions. Also nice to be able to use goal seek to tell you what pressure you need to get a specific level of carbonation.
Bare in mind Gauges on regulators are rarely all that accurate, you can get digital and precision gauges but never seen a "cheap" precision gauge. The temperature in a fridge can vary a lot (up to 5oC) top to bottom, a small fan will keep it homogeneous. I have seen the carbonation change a lot between the start and finish of the keg, play with the numbers above but at the same pressure if the top of the keg is 3oC warmer than the bottom the amount of dissolved will change accordingly.
Mark

Thanks for that, I downloaded the metric chart. I will keep my eye out for an accurate guage. I definitely need to get a fan, do people generally use a computer fan?.

I find that carbonation increases as I progress through the keg.

 

[Dark Maiden]

Thanks for that, I downloaded the metric chart. I will keep my eye out for an accurate guage. I definitely need to get a fan, do people generally use a computer fan?.

I find that carbonation increases as I progress through the keg.

I have found the opposite with this beer. The more i go through, the more flat it goes.

And here I thought kegging was going to be simple compared to bottling

 

[pirateagenda]

e

Re - metric, totally agree, my brew log and all measurements are in kg & kPa, I prefer it this way.
Although PSI seems to be a commonly understood UoM... But, try looking up "BIAB water to gran ratio" - f. me, what is 1lb to 2.5qt? 0.45kg to 2.37 litres (NOT liters)?
/// vented out

even better - I have seen volume referred to as "cubic liters" by the seppos.

 

[brewgasm]

I have found the opposite with this beer. The more i go through, the more flat it goes.

And here I thought kegging was going to be simple compared to bottling

It is simple when compared to bottling big plus here is its in a keg so you can fix it, if the beer was in a bottle you are stuck with the carbonation issue.

 

[Dark Maiden]

It is simple when compared to bottling big plus here is its in a keg so you can fix it, if the beer was in a bottle you are stuck with the carbonation issue.

Touche. And the added bonus my Mrs doesn't see empties everywhere when kegging, so has no idea how much I have drunk when she gets home hahaha

 

[brewgasm]

Touche. And the added bonus my Mrs doesn't see empties everywhere when kegging, so has no idea how much I have drunk when she gets home hahaha

Lol yup just an inconspicuous lone glass on the kitchen counter in the morning

 

[theQuinny]

Lol yup just an inconspicuous lone glass on the kitchen counter in the morning

I'm convinced - the reason for kegging is right there