Balancing Your Draft System

Pictured: Keg King Homebrew Kegerators – first kegerator designed for homebrew

I had the pleasure of attending the National Homebrewer’s Conference held in Grand Rapids, Michigan (in 2014).  If you didn’t have the chance to go, or even if you did, the AHA will be providing recordings of every seminar held at this year’s NHC.  In fact you can pick up recordings going back to 2012’s conference.  This is a member’s only benefit.  If you’re not a member of the AHA, I think you should consider joining.  Access to conference materials is only one of many benefits.  Join nowCheck out the benefits.

One of the sessions I attended was Tom Schmidlin’s “Draft System Design and Maintenance”.  Having built several kegerators over the years, clarification – several iterations of the same kegerator, I feel like a know a fair bit about putting together a system.  Many things were re-affirmations of lessons I’ve learned.  I did pick up a few new tips.  Thank you to Tom Schmidlin for putting on this great presentation!

Note that all of these ideas are not exactly notes from Tom’s presentation.  I specifically note items that I recall picking up from him.  All three “What I learned about Draft Dispensing at NHC” are from Tom’s presentation.

On to setting your temperatures and pressures and balancing your system…

Temperature and Pressure:
The carbonation level of your beer is a function of your CO2 PSI and your kegerator temperature.  The colder your kegerator, the more CO2 your beer will absorb.  You need to decide two things: How cold do I want my beer to be and what carbonation level do I want to serve it at.

1.  Carbonation Level.  Typically expressed in volumes of dissolved CO2.  Check out the BJCP’s style guidelines for a starting point.  The guidelines give general terms like low, moderately low, high, very high, etc.  Other more specific charts and tools are also available.  Most recipe formulation tools have guidelines or tools on the subject including BeerSmith and Brewer’s Friend [Free Non-Expiring Trial].  Tasty Brew’s Carbonation Calculator also has built in guidelines.

2.  Temperature.  Tom said that most bars serve between 34 and 38 deg F.  Of course, this is a personal preference.

After you have determined carbonation level and temperature you’d like you can use a carbonation chart or calculator to determine what pressure you need to store your beer at.

Beer Carbonation Chart Temperature Pressure VolumesClick To Enlarge.  This graphic is found all around the web.  I believe that credit goes to the great John Palmer of How to Brew fame although I’m not 100% certain.

Example:  If you’d like your beer to be 38 degrees and you want 2.4 volumes of CO2, you would find 38 degrees on the far left hand column and then follow it over to the right until you find something similar to 2.4.  After you have located that, follow that column up and you’ll find your required storage and serving PSI.  In this case, 10 PSI.

 

Balancing Your System:
Now that you have your beer at your preferred temperature and carbonation level you need to be able to dispense it at the proper speed and without excessive foam.  A common goal is 1 gallon per minute or about 2 ounces per second.  That’s accomplished by balancing your system.  Essentially, you want to offset most of the pressure (all but about 1 PSI) that is required to store and carbonate your beer with resistance in your system.  Everything on the liquid side of your system counts toward this resistance.

Some resistance estimations…

Tubing – credit goes to the Draught Quality Manual for these figures:

  • Vinyl 3/16” ID 3.00 lbs/ft
  • Vinyl 1/4” ID 0.85 lbs/ft
  • Vinyl 5/16” ID 0.40 lbs/ft
  • Vinyl 3/8” ID 0.20 lbs/ft
  • Vinyl 1/2” ID 0.025 lbs/ft
  • Barrier 1/4” ID 0.30 lbs/
  • Barrier 5/16” ID 0.10 lbs/ft
  • Barrier 3/8” ID 0.06 lbs/ft
  • Stainless 1/4” OD 1.20 lbs/ft
  • Stainless 5/16” OD 0.30 lbs/ft
  • Stainless 3/8” OD 0.12 lbs/ft

Note:  Most Homebrewers that I know use either 1/4″ or 3/16″ ID Vinyl with the majority of those using 3/16″ ID Vinyl.  Lower resistance options are typically used by commercial establishments that are usually trying to reduce resistance.

Note: More Beer has recently EJ Beverage’s Line of PVC Free, Antibacterial, Low Permeability Tubing.  Each of those options include estimated lbs of restriction per foot.  Check that tubing line out – Here

Other:

  • Standard Faucet and Shank – Tom estimates 5 lbs for these items
  • Picnic or Cobra Faucet – .5 lbs
  • Rise in elevation – .5lbs/ft of rise, measured from the center of the keg

Example: Continuing our previous example, we had our pressure set to 10 PSI.  Everything on the liquid side of the system counts toward the system’s resistance.  Let’s say you’re using a picnic tap and 3/16″ ID Tubing.

Picnic Tap = .5 lbs
Estimated Rise from Center of Keg = 2 ft = 1 lb

Total = 1.5 lbs of resistance

That leaves us 7.5 lbs that we need to use up.  We’re using 3/16″ ID Tubing (3 lbs/ft).  We’ll need a total of 2.5 ft of tubing to offset the required pressure.

The total system looks like this…
Picnic Tap = .5 lbs
Estimated Rise from Center of Keg = 2 ft = 1 lb
2.5 ft of 3/16″ ID Tubing = 7.5 lbs

Total = 9 lbs of resistance

Remaining = 1 PSI to serve beer

But wait… you should double the length of the tubing.  Why you ask?…

What I learned about Draft Dispensing at NHC #1 – “Estimates aren’t always right”
Estimations for the resistance of vinyl tubing per foot are… wrong.  Practically I’ve know this for years.  Some time ago I tried to serve a Hefeweizen at traditional carbonation levels (3.6 to 4.5 volumes of CO2) using these figures.  Didn’t work.  Tom’s suggestion: Double the amount of vinyl tubing called for and trim until you get an acceptable flow rate of about 1 gallon per hour and a good pour.  Along those lines, Tom also suggested buying your tubing in 100 foot rolls.

I received two more revelations…

What I learned about Draft Dispensing at NHC #2 – “Longer Shank = Less Foam”
A longer shank means… a colder faucet.  More mass inside your kegerator or keezer keeps your faucet colder and reduces foam.

What I learned about Draft Dispensing at NHC #3 – “Safety First”
Tom’s advice is… Do not place your kegerator in your basement.  A catastrophic failure could cause the tank to drain, flooding your basement with CO2.  Tom also recommended the use of a CO2 Alarm.  He said he got his at Amazon.  He, rightly, mentions that these are difficult to find and a bit on the expensive side.  Carbon Monoxide alarms abound, CO2 alarms are more rare.  In fact if you search for “CO2 Alarm”  on Amazon, the site believes you’ve mistyped and instead shows you Carbon Monoxide Alarms.  This altered search helps a bit, specifically excluding the term monoxide.  It seems some units only report CO2 levels without issuing an alarm.  Here are a couple of models that have alarms: Indoor Air Quality Meter and Supco IAQ50 Wall Mounted Indoor Air Quality Monitor.  As for me… my kegerator is in… my basement and I have a… 20 lb CO2 tank.  At this point, I’m not planning to move it.  However, Tom’s recommendation to use a CO2 Alarm, sounds like a good idea.

Serving Beers with Multiple Carbonation Levels:

If you want to serve beers at different pressures you’ll need multiple regulators…

This is a secondary regulator meaning that it has no high pressure gauge or connection.  This hooks on to your existing primary regulator and allows you to serve additional pressures. You get one pressure per secondary regulator body.

Tip: you can get one additional pressure out of a primary/secondary regulator setup.  Set your primary regulator to your highest desired pressure level, put in a T or manifold on the primary outlet and feed the secondary from there.

A five way secondary via Brew Hardware is pictured.  Brew Hardware has a great selection of Primary and Secondary regulators at generally great prices.

 TAPRITE T752HP-02 DUAL PRESSURE TANK MOUNT CO2 REGULATOR MFL OUTPUT

Taprite Two Pressure (3 Gauge) CO2 regulator.  Both valves have valves.  Features adjustment knobs for easy pressure adjustment.  1/4″ MFL connections.

This is a double bodied regulator.  It allows you to serve at two carbonation levels.  I currently use a double bodied regulator.  I feed a manifold off one regulator with what I’ll call my standard or house carbonation level – and have a single line going off the other regulator for beers that I want to serve at a different carbonation level or for force carbing a keg at a higher pressure.

If you simply want to split one of your pressures for use in multiple kegs, a manifold will do the trick.  These give you multiple tubing runs, have integrated check valves to prevent cross contamination and have valves to control each link.  The list of things that grow with you in homebrewing is… short.  You can’t add on two gallons to your brew kettle.  This expandable manifold system from More Beer is one thing that will actually grow with you.  Check out my Hands on Review of this great system.

Additional Resources and Related Products:

This is a Top Post! See: All Top Posts

Recent Great Deals [view more]:

toppost:balancingyourdraftsystem

8 thoughts on “Balancing Your Draft System

  1. shaughn

    can we PLEASE stop equating force and pressure? Tubing resistance should not be cited in force/length if you are directly comparing it to the serving pressure *total length of resistance in your system. This is flat out wrong, 9 lbs is not equal to 9 psi. Yes, i know everybody does it but it’s still wrong. Either tell tubing folks to have resistance numbers in psi/ft if you’re balancing method is to just have appropriate length.

    Reply
  2. Rob Farrell

    CO2 risk is small unless you have a tiny basement. From my Chemical Engineering knowledge: 20 lb of CO2 is 9,071,850 mg. My basement is 28 x 38 x 7 = 7448 cu ft = 210,897 liters

    ppm is mg/l = 9071850/210897 = 43 ppm. 2000 ppm is hazardous. Don’t panic

    A dangerous level of CO2 is 2000 ppm

    Reply
  3. 4 Dog Brewery

    I always turn my tank off after every serve. I have had my 20 lb. tank in my basement for 11 years.

    Reply
  4. JPena

    Great article, we’re currently in the process of building a keezer and this turn out to be a really good read.

    Reply
  5. Anonymous

    Wow . Got to say that I did not think of co2 flooding the basement. Have 20lb co2 tank and will probably move out of basement to garage

    Reply
  6. Anonymous

    Great summary of the talk. I was there also and these things learned were what I took away too. Now I just need to get the rest of my set up done.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *