Naturally carbonating in the keg

[brownni5]

Lots of threads on the topic, but too many to wade through.

I want to prime and naturally carbonate a farmhousy/ saisonny thing I have going on. Since I'm still new to kegging, I haven't done this before and am unsure how much priming sugar to add. Going by the bottling calculators out there would over carbonate, no? If I use a spunding valve, would it matter? If I under carb, that can be solved when on gas, so can I really go wrong here?

 

[pvpeacock]

If you use a spunding valve set to the correct pressure for your temperature and desired carbonation volume, you can use the same amount of sugar as for bottling. For example, I use 1 cup of sugar and set my spunding valve to 30 psi when naturally carbonating at 70 degrees. That puts me at about 2.3 volumes. I've noticed that when I put the keg in the keezer after its carbonated, the spunding valve psi drops to about 10-12 psi when the keg cools to 40 degrees F. That confirms it is right at around 2.4 volumes.

Alternatively, if you don't have a spunding valve, I would use less sugar than bottling and then make up any under-carbonation when you put it on bottled gas. Better to under-carbonate that over carbonate.

 

[mirthfuldragon]

One thing is that you'll still probably have to use gas to ensure a good keg seal. I hit my with 40psi initially and then check for leaks.

 

[bleme]

I usually use 125 grams of sugar then purge 6 times at 30 psi. If it is off, it's never by much and fixes itself when I put in on gas.

 

[LittleRiver]

I usually use 125 grams of sugar...

Assuming room temperature, ~70deg, what's the minimum amount of time you leave it before you chill it for serving?

 

[Dgallo]

Assuming room temperature, ~70deg, what's the minimum amount of time you leave it before you chill it for serving?

Really depends on how active and healthy the yeast were that were still in suspension in the beer your priming. It can be carbed in as little as 3 days if the yeast were still really active. average for me is 9. That being said, your better off waiting 2 weeks so that you are sure it is carbed. If your keg carbonating to begin with, your already planning to have patients so dont rush it. If you needed it done quick you might as well have force carbed it by agitation. That method you can drink your beer 6 minutes after going from the FV to the Keg.

 

[#p3brews]

I usually use 125 grams of sugar then purge 6 times at 30 psi. If it is off, it's never by much and fixes itself when I put in on gas.

nearly a quarter pound of sugar for how many gallons? let sit 2 weeks at 70' and this was for a farmhouse/saison, so then more sugar for desired 3.2 volumes? trying to calculate for 5 gallon corny or 1/4 barrel.

 

[bleme]

nearly a quarter pound of sugar for how many gallons? let sit 2 weeks at 70' and this was for a farmhouse/saison, so then more sugar for desired 3.2 volumes? trying to calculate for 5 gallon corny or 1/4 barrel.

https://www.brewersfriend.com/beer-priming-calculator/
This will get you in the ballpark. The fuller your keg, the less headspace you have, the less sugar you need, so there is an inverse relation going on that makes keg priming even more forgiving.

 

[ChiknNutz]

I am confused. One the last recipe I did, it said to use 1/2 the amount of priming sugar if kegging vs bottling. Furthering my confusion is the addition of sugar at all if using CO2 to "naturally carbonate" as I thought the CO2 gas was all the CO2 needed to carbonate. Clearly missing something here. Sorry to sound ignorant, but I am still.

 

[bleme]

You can't naturally carbonate using bottled CO2. That is just to purge the headspace. I have tried it with half the amount of sugar and it just wasn't carbed enough. I might reduce it by .5-1.0oz because you have proportionally less headspace but 2oz of sugar only gave if cask-style level of carbonation.

 

[pvpeacock]

There are 2 main ways to initially carbonate a keg: 1. hook it up to a CO2 tank or 2. add priming sugar (aka "narturally carbonate"). Carbonating by hooking up a CO2 bottle is NOT "naturally carbonating." However, there are multiple ways to carbonate using a CO2 tank : 1. "Set and forget" where you set the regulator to serving pressure and let it sit a week or two to reach the proper carbonation level, 2. "Force carbonate" where you shake the keg to get it to absorb CO2 quicker or 3. something in between like setting the pressure at 35-45 psi for 24 hours and then reducing to serving pressure.

I, too, have read that you only need half the priming sugar for a keg if naturally carbonating,, but have not found that to be true. That is why I use 1 cup of sugar and then use a spunding valve set at 30 psi at 70 degrees just in case that amount of sugar overshoots my desired carbonation level.

 

[ChiknNutz]

You can't naturally carbonate using bottled CO2. That is just to purge the headspace. I have tried it with half the amount of sugar and it just wasn't carbed enough. I might reduce it by .5-1.0oz because you have proportionally less headspace but 2oz of sugar only gave if cask-style level of carbonation.

Thanks for the clarification, I mixed up the terms in regards to what is natural carbonation.

 

[bleme]

You can also naturally carbonate by spunding or krausening.

With spunding, you transfer the beer while it is .003 or more points above final gravity and connect a spunding valve to release excess pressure.
Krausening is when you save a portion of your wort and add it back in when you keg.

 

[Vale71]

Krausening is when you save a portion of your wort and add it back in when you keg.

That's actually Speise. Kräusening is when you add freshly pitched and fully fermenting wort from a subsequent batch (works best if it's the same recipe ).

 

[LittleRiver]

@bleme is it your practice to use a spunding valve when you're carbonating a 5gal keg with a cup of sugar?

 

[troglodytes]

So I'm doing this for the first time, myself, with a saison. I transferred to the keg with .003-.005 left to go based on my estimate. I have a spunding valve I got as a gift that does not appear to be adjustable and maxes out at 15 psi. It has been sitting for 3 days. When I transferred to keg at 70F I hit it with 10 psi to seal the keg, and set in the corner at 70-72F. Over the past 3 days the psi on the spunding valve gauge shows that is has crept up to 14 psi today. My assumption is that once it hits 15 psi it will just release the excess pressure.

Does this mean that beer will only be carbonated to like 1.8 vols by the time its done fermenting?

Should I just take off the spunding valve and let the keg get to whatever pressure it naturally gets to?

 

[bleme]

@bleme is it your practice to use a spunding valve when you're carbonating a 5gal keg with a cup of sugar?

I don't have a spunding valve so I usually only use 3-4.5oz of sugar (depending on style)