Author Topic: Spunding and serving psi  (Read 641 times)

Offline Jayborracho

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Spunding and serving psi
« on: September 16, 2021, 05:50:59 pm »
Hi all, when you carb your beer naturally thru spunding, at what psi should you push it out of your kegerator when it’s time to serve? I’m assuming since it’s already carbed maybe something like 5 psi as to not mess with the delicate carbonation?

Offline RC

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Re: Spunding and serving psi
« Reply #1 on: September 16, 2021, 06:21:11 pm »
Depends on 1) temp of the kegerator, 2) length of the tap line, and 3) style of beer and desired volumes of CO2.

Assuming your tap-line length is typical, and assuming a typical carb of ~2.5 vols at typical kegerator temps, you'll want to dispense at 10-12 psi. Under these assumptions, 5 psi would only be useful for an extremely cold imperial stout.

My kegerator temp is set to 37F and I keep the regulator at 9-10 psi. My kegs have very short lifespans and so I do not worry about slight over/under-carbonation.

Offline BrewNerd

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Re: Spunding and serving psi
« Reply #2 on: September 17, 2021, 08:53:27 am »
Had to look up what "spunding" is.

https://www.precisionfermentation.com/blog/natural-beer-carbonation-spunding/

As simply as I can figure, spunding is using the CO2 produced in the later stages of your beer's primary fermentation to carbonate itself without the addition of extra priming sugars or added gases.

A spunding valve allows a set pressure to develop in the fermentation vessel and releases any extra pressure. The higher you set the spunding valve, the more CO2 is forced into your beer and the greater the carbonation. Set it too high and you turn your fermentation vessel into a bomb.

That's fascinating and extremely clever.



Oddly, not mentioned in the Oxford Companion to Beer or How to Brew. I swear it's a real thing!

Best of luck and thank you for the vocabulary lesson.

Offline ynotbrusum

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Re: Spunding and serving psi
« Reply #3 on: September 19, 2021, 07:19:04 am »
I balance the pressure by putting a head pressure on the receiving keg of 2-4 psi lower than the fermenting vessel and attach CO2 on the fermenting keg to maintain its pressure (say 10 psi on the fermenter and 6-8 psi on the receiving keg.). It keeps foaming down.
Hodge Garage Brewing: "Brew with a glad heart!"

Offline erockrph

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Re: Spunding and serving psi
« Reply #4 on: September 19, 2021, 08:47:54 am »
Depends on 1) temp of the kegerator, 2) length of the tap line, and 3) style of beer and desired volumes of CO2.

Assuming your tap-line length is typical, and assuming a typical carb of ~2.5 vols at typical kegerator temps, you'll want to dispense at 10-12 psi. Under these assumptions, 5 psi would only be useful for an extremely cold imperial stout.

My kegerator temp is set to 37F and I keep the regulator at 9-10 psi. My kegs have very short lifespans and so I do not worry about slight over/under-carbonation.
This ^^^

It doesn't matter how the carbonation got into your beer in the first place (priming, spunding, or force-carbonation). Once your beer is fully carbonated, then the same rules of equilibrium apply for carbonation vs CO2 pressure vs temperature, as well as balancing your lines.
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer