Carbonation methodology

[DryStout]

Hi All,
Recently we have had some issues with the carb levels on some of our beers. My method had been to transfer the brite beer into the BBT (usually at 33-34*) then run my carb stone (near the bottom of the tank but not all the way down) starting at 15PSI an slowly coming up to about 25-30PSI as needed.
I have tested the beer with a zahm an I'm getting a reading of 2.4 but the level does not feel that high when drinking the beer.
Any thoughts on how to get a better carb level on the beer ?

[GlacierBrewing]

Hiya' Drystout,
I carbonate my beers to 2.8-3.0 on a very regular basis. Using a technique I learned from the master, Sanford Jones, I carb in the BBV using a carb stone in the bottom of the tank. I try to get the tank's contents very cold, like 29-30 degrees F. I put 15-20 psi head pressure on the tank. I push CO2 in (through the stone) maintaining the tank pressure while bleeding pressure out of the tank. I can get a 10bbl tank of beer (filtered or not) carbonated to 2.9 volumes in around 7-9 hours.
Hope this helps.

Prost!
Dave

[ATB Consulting]

DryStout,
2.4 is a bit low. Most beers on the market are about 2.55 or higher depending on the style. Btw, what is the head pressure on your tank? Your temp is fine unless you have a low gravity beer at which point I would set your temp at 34 - 35 unless you want to make an ice beer

[Junkyard]

Hi All,
Recently we have had some issues with the carb levels on some of our beers. My method had been to transfer the brite beer into the BBT (usually at 33-34*) then run my carb stone (near the bottom of the tank but not all the way down) starting at 15PSI an slowly coming up to about 25-30PSI as needed.
I have tested the beer with a zahm an I'm getting a reading of 2.4 but the level does not feel that high when drinking the beer.
Any thoughts on how to get a better carb level on the beer ?

We are currently carbonating in kegs, which works fine for us.

I have heard the best method to carbonate bright tanks is as follows: With a stone placement just like you have, turn the pressure up to 15 psi, and let it slowly bubble until the tank pressure equalizes. Then an hour or so later, let it the head space bleed off halfway, and turn on the pressure to 15 psi again until the tank equalizes as before. Continue this process a several times throughout the day. The temperature and amount of times you repeat the steps will obviously have an effect, but what matters is being consistent once you have found the way that works. having easy steps to follow makes it easy to be consistent.

-Dan

[gitchegumee]

Whole lot of other threads out there on this same topic. As I've said before many times, if you are "bleeding" pressure, I think you're doing it wrong. Please search for more information.....

[Larry Doyle]

Hi All,
Recently we have had some issues with the carb levels on some of our beers. My method had been to transfer the brite beer into the BBT (usually at 33-34*) then run my carb stone (near the bottom of the tank but not all the way down) starting at 15PSI an slowly coming up to about 25-30PSI as needed.
I have tested the beer with a zahm an I'm getting a reading of 2.4 but the level does not feel that high when drinking the beer.
Any thoughts on how to get a better carb level on the beer ?

The good news is that you are actually testing the CO2 level and your test results match your sensory results. As previously noted 2.4 vols does not taste "that high" because it really isn't "that high."

[TL Services]

+1 for Larry's post - testing and, so, knowing what the real numbers are is the only way to ensure consistency with carbonation.

There are only two factors that control carbonation level: Pressure and temperature...

Higher pressure = higher carbonation
Lower temperature = higher carbonation

Time is a factor, but only in that it takes time for CO2 to dissolve to equilibrium within the tank (which is why, as Philip mentioned, venting pressure is contrary to the physics that control gas dissolution). Smaller bubbles (ie. finer stone porosity) will help too.

Because of the mechanism of dissolution, regular measurement during carbonation will allow you to control the process; and even after completion you may see something of a rise in results as any CO2 microbubbles take time to reach a genuinely dissolved state.

[DryStout]

Thanks of the replies all. It seems I have been not carbonating to a high enough level and possibly kegging my beer too soon. Would waiting overnight after reaching a zahm reading of 2.62 help my carbonation levels/ perception? Any chance I'm not carbonating the entire volume of beer evenly ?
WatenENG... How do I get those nice fine bubbles into my kegged beer ?
Thanks again guys !

[TL Services]

DryStout,

You are not looking for fine bubbles, whatever is said here. Genuinely dissolved CO2 is not a bubble, but molecules of CO2 intimately mixed within the liquid.

As I mentioned earlier, during carbonation, initially, much of the the CO2 forms microbubbles. These are inherently very stable but, over time, the CO2 becomes truly dissolved. At this stage it produces a weak acid (carbonic acid), which is what makes carbonated soft drinks (eg. Coke, etc.) acidic.

We used to allow around 30 metres (around 100ft) of main between our CO2 injection point and the inline CO2 sensors; this gave a good level of accuracy for results, but didn't mean we had to have an excessive length of main before the bright tanks. That should give some indication of the time required to achieve close-to fully dissolved.

The reason soft drinks have large bubbles is that they are carbonated to a much higher level than beer so require a much higher CO2 partial pressure to keep the gas dissolved. Taking the cap of a bottle of Coke (or other) creates a sudden pressure drop and, hence, a rapid inequilibrium in the conditions (effectively the CO2 partial pressure all-but disappears for practical purposes) and thus the dissolved CO2 comes out of solution very rapidly and in great quantity - hence the big bubbles.

As previously said, there are only two factors that govern the level of carbonation - pressure and temperature.

If you use a stone/sinter with a fine porosity, you will introduce bubbles that are smaller, which will help dissolution as the total surface area of all the small bubbles will be greater than fewer, larger, bubbles. This will have no effect on the ultimate level of carbonation, but will help you to reach dissolved equilibrium more efficiently.

Hope that helps!

[DryStout]

Thanks KWLSD
I have my next batch I. The BBT as of yesterday. I carbed overnight with the beer starting out with a head pressure of 5PSI. I set the pressure begin my carb stone to 17PSI and opened the valve on the CO2 line about half way. Came in this morning to find my head pressure at 11 PSI and the beer at 2.43 volumes (going higher on carb this time) I continued running the stone slowly (so I could just barely hear it running) until I reached 13PSI head pressure and got a zahm reading of 2.61.

Will more time in the BBT, without running the stone help me to reach equilibrium and have a better carbonated product in kegs ?

[TL Services]

Leaving it 'as is' (ie. with pressure but no CO2 flow) I would expect to see two changes overnight:

- The pressure will decrease
- The CO2 reading will increase

Why?

If you consult your Zahm solubility table you will see that 13psi at 34 deg F should give you 2.90v/v of CO2 at equilibrium, so if you measured 2.61v/v at 13psi and 34 deg F, then the beer has the ability to 'hold' more CO2 in solution.

As more CO2 goes into solution (and as you're not adding more, it can/will come from the tank's headspace) the tank pressure will drop. This means the maximum dissolved level will be less than the figure of 2.90v/v (as above).

Imagine a graph with two lines on it - one going up (= dissolved CO2), the other going down (= tank pressure) - then equilibrium is the point where the two lines cross. At this stage both the CO2 measurement and the pressure will not change further.

[Greenbushguy]

We have an 8" stone in our 15 BBl brite and a 12" in our 30 BBL brite and we can usually carb them up to 2.6 - 2.7 in about 2.5 hours. We run 30psi and 50 psi respectively on our brites/stones. Why is everyone else going so slow and low? Our tanks have a 30 psi limit on them and we only usually have to bleed a little pressure off once or twice. Am I missing something?

[zorbenkidu]

Step Up Carbonation

We have an 8" stone in our 15 BBl brite and a 12" in our 30 BBL brite and we can usually carb them up to 2.6 - 2.7 in about 2.5 hours. We run 30psi and 50 psi respectively on our brites/stones. Why is everyone else going so slow and low? Our tanks have a 30 psi limit on them and we only usually have to bleed a little pressure off once or twice. Am I missing something?

As discussed above by a few other people, the slower you carbonate the more time the CO2 molecules have to hydrate. Slow, gentle bubbles also don't scrub your beer. You can lose esters and aromas when you blast it with air too quickly. Everyone carbonates differently, but I start off by determining the wetting pressure of the carb stone. To determine wetting pressure you should test your stones in a bucket of water, slowly turning the pressure up on your regulator until a small cascade of bubbles comes from the stone. Then add 1 psi for every 28 inches of beer above the stone. E.G. Stone has wetting pressure of 5 psi, and there is 84" of beer above the stone. Therefore wetting pressure is 8 psi. Obviously, you have to check your stones before you fill the tank. A word of caution, wetting pressure and porosity in stones do change over time. Checking regularly is a good idea.

If you start at the wetting pressure you should bump up by 1 psi every half hour until you get to your desired flow to reach your volumes of CO2. Determine this by your temperature and your zahm and nagel chart. 2.6 volumes is a good solid number to aim for if you're bottling or canning (unless you can keep your brite tanks at 32 or less it's pretty touch and go to package your product due to foaming problems). If you're kegging 2.8 volumes is great, because you tend to lose a little bit of perceived carbonation just by pouring your beer on tap. So if you're aiming for 2.6 volumes, and your beer is at 34 degrees, you want to add 10 psi to your wetting pressure of 8 psi to reach 2.6 volumes. Therefore, you'll start at 8 psi, and over the course of 5 hours build up to 18 psi and then leave it there until you get a zahm and nagel reading that you're happy with.

You don't have to do this. It's called step up carbonation, and limits the amount that you scrub the esters and aromas out of your beer, makes tighter bubbles, and is a lot slower than blast carbonating. I find it to be a happy medium between the harsh soda fountain bubbles from in line carbonation and beautiful, tight, creamy champagne bubbles.

Carbonation will happen faster the more amino acids and proteins you have in your beer for it to grab onto. I make hard cider, so we have almost no amino acids, and it usually takes 2 days for us to reach our desired CO2 levels. It should be less than 24 hours for most beers.

I don't know why people would bleed the pressure out of the head space to accelerate the rate of carbonation, or even how, why, or if that works. Personally, the only time I bleed the head pressure is when I'm trying to take the carbonation level down. If you come in at 2.9 and want to be at 2.6, you bleed the head pressure out and close it up again. After 6-8 hours some CO2 will come out of solution to reach osmosis in the tank between the dissolved CO2 and the head pressure. Measure again and if you have to, you can repeat the process. Every tank is different, but in my tanks, bleeding the head pressure and allowing it to reach equilibrium again usually drops my cider by .15 volumes or so.

What I've found with carbonation is that even though there is an exact science behind how it works theoretically, in practice you have to find what works for you with the equipment you have and the kooky things that happen when you have the least amount of time to deal with them. If blasting your tanks at 50 psi works for you then keep on doing it. If you're curious to see if there's a difference (like I was), try both and taste them side by side. I find that the mouthfeel is exponentially better the slower you go. Also, the longer you give your product time to age and the CO2 to hydrate in your keg, can, or bottle, the better it's going to be.

Beware of freezing regulators on your dewars, especially if you're carbonating overnight. I have a heater that hooks on before my regulator to keep that from happening, but it still doesn't always work. Beware of running out of CO2, because if you don't have pressure long enough beer will shoot back up the lines and into your regulators. I switched all my regulators over to stainless so that I can CIP my carbonation system (just put a little valve between your gauges and the regulators because you can't get them wet). You're going to have to change gauges every once in a while, they aren't very durable. Also, if you have a regulator that tends to jump on you (i.e. you set it at 20 and you walk away and come back and it's at 24) take it apart, clean it, put it back together, and if it still doesn't work right, replace it. It's better than constantly accidentally over or under carbonating.

Everything I have said here is information I have accumulated by talking to brewers and dealing with trying to carbonate a beverage that really does not like to dissolve CO2, but nothing is absolute. The bulk of it I learned by reading Carbonation Demystified by Dave Meheen (http://www.meheen.com/wp-content/upl...emystified.pdf). I'm still learning and experimenting. If you have any advice to add or change, or you disagree with me, please let me know. We're all in this together. Good luck and cheers!

[BDL]

So the reason to bleed off, is that you can bring the whole tank to a pound or two more pressure than you need to hit your desired volumes for the temp that the beer is at. Then you bleed off and inject through your stone to maintain a flow of co2 at close to the right pressure effectively increasing the surface area and thereby speeding the speed at which the beer reaches dissolution equilibrium. It definitely works. We can get 60BBLs of beer to 2.6 in under 4 hours or so. There is a lot of debate about aroma scrubbing, but we make some very aroma heavy IPAs that stand up well... So YMMV

[zorbenkidu]

That makes a lot of sense. Because I make hard cider, aroma is vital, and I have done side by side trials of faster and slower carbonation, and we definitely lose something when we carbonate faster. However, our cider is cross flow filtered and has a lot more flimsy molecule chains than IPA or pretty much any other stouts, browns, etc.. I would contend (though I haven't done side by side trials) that Pilsners, Whits, and Lagers might lose a little something being carbonated this way. Thanks for explaining the science behind it though, I didn't understand why cracking the valve helped until you put it that way.

As you said, to each their own. I would just advise anyone trying to decide to run a trial. I've got two corny kegs that I welded a threaded sparge stone onto the gas tube at the bottom of the keg. I do a lot of carbonation trials in these things, and I will run some trials with various types of beer soon and let y'all know what I think.