Wednesday, June 12, 2013

Calculating (Homebrew) Kegging PSI and Hose Length

"At what PSI should I carbonate my beer?"
"How long should the tubing be?"

These are important questions you need to ask when kegging your home-brew.  

"Why?" You ask.
"Can I not just hook up the tubing and crank up the PSI on my CO2 tank and just let it go?" You ask.

Well the honest answer is, "Yes. You can." Well... you can if you want a big glass of yummy foam, that is.

After home-brewing for nearly 7 years, I have finally transitioned to kegging my beer.  My first beer is currently being carbonated in my DIY kegerator.  But since I didn't have the answer to the two questions at the top of this article, I had to research on my own for the answers I needed.

I called my local homebrew store for recommendations on which type of hoses/tubing to use.  They recommended 5/16 ID for the CO2 lines and 3/16 ID for the Beer line.

The CO2 lines don't really make that much of a difference since the pressure in the tube a keg eventually regulate themselves at whatever you set the pressure at. For mine it took a couple days of constant attention, but it finally leveled off at the pressure I had set it.

When the home-brew store said what the length was, I got a little nervous because I'd been reading contradictory information on all of the beer forums.  One forum would say no less than 7 feet. While another forum would say 3 feet is fine.  But my local home-brew store said between 3-4 feet was fine.

Well, what I found out, later on, was that they were all, technically, correct. 

"Why?" you ask.

Simple.  The easy answer is that the PSI that you set your regulator at is directly proportional to the length of the lines.

Essentially you can make your tubing as long (or short) as you want as long as the pressure is set proportionally.

Basically, the longer the lines, the higher the PSI. (And vice versa).

I found a website (I put the link at the bottom of this article) that finally explained EXACTLY what my PSI needed to be.  And EXACTLY how long my lines needed to be.

Every child from 1st to 12th grade always asks when they are ever going to use that stupid math once they're out of school.
Get ready for that 9th grade algebra to come in handy.


L = (keg_pressure - 1psi (H/2) ) / Resistance 3

This equation does come in handy, but based on my experience, I would take the results with a grain of salt.

I followed this equation to a T and my beer ended up being over-carbonated and I was just getting a glass of foam and flat beer.

So what I would suggest is to visit the links I've posted below (especially the first link).
If you have problems, do a search on google or bing for "Keg Balance Calculator"

How did I fix my over-foamed problem?  After searching the internet for "homebrew keg is foamy+how to correct"  I found some forum posts that led me to my answer.

Essentially what I did was:

  1. Turn off the co2.
  2. Bleed the CO2 from the keg.
  3. Let it sit for a few hours.
  4. Then turn the keg back on to a low psi (5).  Try to dispense.  The beer came out very slowly (almost a trickle) but I was checking for mouthfeel.  Once I was confident that the mouthfeel was good, I proceeded to the next step.
  5. I turned the psi up to 10, then tried to dispense once again.  This time the beer came out at a normal level.  The foam was good and the carbonation was good.  I think it's fixed.
  6. I tried one more move up to 12 psi.  This time it was perfect.
  7. I set the CO2 regulator at 12psi and left and it's been good ever since.

Online Calculator:

PSI Chart

Explanations of equations: