Diffusion Stone for Carbing

[ZmannR2]

So as I always do, I was browsing around on AHS and came across this diffusion stone.You can use it to carb beer in a keg or oxiginate wort. Speaking only on the carbing part, check out the description:

To use a diffusion stone to force carbonate beer, champagne, or sparkling meads, you will need a homebrew kegging outfit with CO2 tank, regulator, lines, and a keg. Simply attach a 24" length of 1/4" ID tubing to the gas side dip tube of your keg with a worm clamp. On the other end of the tubing, attach the diffusion stone. There are charts available online and in books for exact levels of temperature and CO2 pressure to achieve desired carbonation levels. The following is an example for average carbonation in beer: Chill the beer to 40 F. Adjust the regulator to 2 PSI and attach the gas disconnect. Every 3 minutes increase the pressure 2 PSI until 12 PSI is reached. At this point the beer will be carbonated, but it won't hurt to leave it alone in the refrigerator for a few days under pressure.

Say whaattt? This is awesome! Has anyone tried these things? They're only $14 here:

http://www.austinhomebrew.com/Diffusion-Stone-0-5-Micron.html





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[casualbrewer]

Interesting

 

[antony]

& I thought I understood the science behind carbonating...not sure I understand how the stone would make a difference.

I was gonna go by ahs later this week...maybe I'll grab one in the name of science. I've got a chocolate stout to carb this weekend anyhow.

 

[Gavin C]

& I thought I understood the science behind carbonating...not sure I understand how the stone would make a difference.

The factors affecting the carbonation level (i.e. volumes of CO2 absorbed into the beer) are the temperature of the beer and the CO2 partial pressure in the vessel's head space.

Over time the pressure head space and the absorbed CO2 in the beer reach an equilibrium.

The speed at which this equilibrium is reached is dependent on the surface area of the liquid/gas interface. Imagine the gas in the head space as 1 cylinder shaped bubble. Surface area of the liquid/bubble interface is the circular area of the cylinder.

Now consider what the diffusion stone does. It creates thousands of bubbles of CO2. All spherical and combined will have a far greater surface area in contact with the liquid. The result is that the equilibrium point is reached more rapidly.

The same occurs with shaking a keg. More surface area is being exposed to CO2 via the agitation and creation of bubbles.

Hope that rambling explanation is of some use.

 

[ZmannR2]

The factors affecting the carbonation level (i.e. volumes of CO2 absorbed into the beer) are the temperature of the beer and the CO2 partial pressure in the vessel's head space.

Over time the pressure head space and the absorbed CO2 in the beer reach an equilibrium.

The speed at which this equilibrium is reached is dependent on the surface area of the liquid/gas interface. Imagine the gas in the head space as 1 cylinder shaped bubble. Surface area of the liquid/bubble interface is the circular area of the cylinder.

Now consider what the diffusion stone does. It creates thousands of bubbles of CO2. All spherical and combined will have a far greater surface area in contact with the liquid. The result is that the equilibrium point is reached more rapidly.

The same occurs with shaking a keg. More surface area is being exposed to CO2 via the agitation and creation of bubbles.

Hope that rambling explanation is of some use.

That's awesome man! Thanks

 

[ZmannR2]

So do you leave the stone in there the whole time you serve from the keg? So the pressure is always maintained through bubbles coming up from the surface? Seems odd

 

[Gavin C]

So do you leave the stone in there the whole time you serve from the keg? So the pressure is always maintained through bubbles coming up from the surface? Seems odd

Typically folks whose use have a lid on the keg with the diffusion stone attached. My guess is they switch the gas QD to the regular gas post on the keg once they have their beer carbed to their satisfaction. You wouldn't want to be agitating the beer unnecessarily while serving with a diffusion stone bubbling. It would potentially kick up any settled yeast/trub resulting in cloudy beer.

Corny Keg lid with diffusion stone

 

[ZmannR2]

Oyyyy!! Well that just turned me off to it. Seems like unessasary work. I was looking forward to carving my beer in 20 mins but that's a little too much stuff to deal with. Damn

 

[Yooper]

Oyyyy!! Well that just turned me off to it. Seems like unessasary work. I was looking forward to carving my beer in 20 mins but that's a little too much stuff to deal with. Damn

If you're in a big hurry, you can still carb an entire keg of beer in a short time. You'd have to shake the keg or something, so I don't do that as it resuspends any sediment.

You could put the keg in the kegerator on 30 psi for 36 hours, and then purge and reset it to 12 psi. It would mean waiting 36 hours for the beer to be carbed, but it would take quite a while for the beer to get cold anyway when you used a diffusion stone, so it wouldn't be cold in 20 minutes even if it was carbed up.

Another way to get carbed up beer really fast is to fill the keg, but put some in a 2L bottle. Then you can use a carbonator cap to carb up the 2L in about 5 minutes.

 

[PapaO]

Now consider what the diffusion stone does. It creates thousands of bubbles of CO2. All spherical and combined will have a far greater surface area in contact with the liquid. The result is that the equilibrium point is reached more rapidly.

You will get thousands of bubbles until the keg pressurizes. Than Co2 flow stops until the Co2 in the head space is absorbed. So will a diffusion stone speed up any thing?

 

[Yooper]

You will get thousands of bubbles until the keg pressurizes. Than Co2 flow stops until the Co2 in the head space is absorbed. So will a diffusion stone speed up any thing?

Yes, it does. It reaches equilibrium faster.

 

[Maylar]

Would this be any different than using the liquid post as a CO2 input?

 

[GilSwillBasementBrews]

Would this be any different than using the liquid post as a CO2 input?

Only thing I can see is you will get more and smaller bubbles with the diffusion stone.

 

[Gavin C]

You will get thousands of bubbles until the keg pressurizes. Than Co2 flow stops until the Co2 in the head space is absorbed. So will a diffusion stone speed up any thing?

The CO2 is being absorbed constantly from the headspace so CO2 flow doesn't stop till equilibrium is reached.

As a result you get a constant and steady inflow of CO2 through the diffusion stone. The inreased surface area (head space/beer interface plus the bubbles) equates to equilibrium being reached more rapidly.

 

[PapaO]

The CO2 is being absorbed constantly from the headspace so CO2 flow doesn't stop till equilibrium is reached.

As a result you get a constant and steady inflow of CO2 through the diffusion stone. The inreased surface area (head space/beer interface plus the bubbles) equates to equilibrium being reached more rapidly.

Yes I get that, but doesn't flow come to a crawl once the keg pressurizes? Co2 can only flow as fast as it can be absorbed. It's not like a fish tank that vents to the atmosphere. What I can't get my head around is, with less flow = less bubbles. It could be the word FASTER. With the set and forget method, if it takes 3 weeks to fully carb, will it carb in 1 week or will it take 20 days? 1 week is faster 20 days not much.

Thank You
PapaO

 

[day_trippr]

The procedure provided at the beginning of the thread kinda goes to that question. By starting out low and periodically increasing the pressure by a small amount you can keep bubbles flowing longer than slamming full pressure on at the start.

Whether that actually shortens the total time it takes to reach equilibrium is out of my experience - I've never used a stone to carb a keg...

Cheers!

 

[Yooper]

Yes I get that, but doesn't flow come to a crawl once the keg pressurizes? Co2 can only flow as fast as it can be absorbed. It's not like a fish tank that vents to the atmosphere. What I can't get my head around is, with less flow = less bubbles. It could be the word FASTER. With the set and forget method, if it takes 3 weeks to fully carb, will it carb in 1 week or will it take 20 days? 1 week is faster 20 days not much.

Thank You
PapaO

No, not really. The diffusion stone "breaks" the bubbles into tiny bubbles that can be absorbed into the liquid (especially if the liquid is cold) and so it doesn't pressurize the headspace first and then "force" it's way down under pressure in the same way. The miniscule bubbles create a huge amount of surface area to help absorb CO2 rapidly into the beer, instead of the surface area of the headspace.

That's why it's so much faster. And it's not one week vs two- it's usually accomplished in hours.

But when I carb up my beer quickly, it starts out warm and I put it in the keg and in the kegerator at 36 psi- and it's chilled and carbed in 36 hours. The carbonation stone would probably be much faster- but the beer has to chill anyway so I have no issue waiting 36 hours.

 

[PapaO]

No, not really. The diffusion stone "breaks" the bubbles into tiny bubbles that can be absorbed into the liquid (especially if the liquid is cold) and so it doesn't pressurize the headspace first and then "force" it's way down under pressure in the same way. The miniscule bubbles create a huge amount of surface area to help absorb CO2 rapidly into the beer, instead of the surface area of the headspace.

That's why it's so much faster. And it's not one week vs two- it's usually accomplished in hours.

But when I carb up my beer quickly, it starts out warm and I put it in the keg and in the kegerator at 36 psi- and it's chilled and carbed in 36 hours. The carbonation stone would probably be much faster- but the beer has to chill anyway so I have no issue waiting 36 hours.

I guess I couldn't get past the flow rate of C02 after the keg is pressurized. I guess it's fast enough to carb in hours.

Thank You
PapaO

P.S. Now I can tell my grandkids I'm not to old to learn something new.

 

[LBussy]

I guess I'm stuck on the adding a gas connector to the lid part ... where does one get parts for that? Never seen them. Never looked for them really I guess.

 

[Gavin C]

I guess I'm stuck on the adding a gas connector to the lid part ... where does one get parts for that? Never seen them. Never looked for them really I guess.

Here is one

I just don't see the need for this type of product. For me it's a solution to a problem that doesn't exist. To each their own though.

 

[day_trippr]

[...]I just don't see the need for this type of product. For me it's a solution to a problem that doesn't exist. To each their own though.

I feel the same way about burst carbing, so...

Cheers!

 

[GilSwillBasementBrews]

But when I carb up my beer quickly, it starts out warm and I put it in the keg and in the kegerator at 36 psi- and it's chilled and carbed in 36 hours. The carbonation stone would probably be much faster- but the beer has to chill anyway so I have no issue waiting 36 hours.

I have to agree with all your post. The only part I COULD see argument for this was if you cold crashed your beer before kegging. In that situation it would already be cold going into the keg so would be more susceptible to the advantage of the stone carb method creating more surface area than just head pressure.

But again I usually have beer carbed and conditioned before I have an open tap to stick it on anyway.

 

[joeg13]

Do you need to use worm clamps to keep it on the post and barb because of the pressure? Seems like it would be hard to clean and sanitize.

 

[GilSwillBasementBrews]

I would think as long as it is releasing the co2 into the beer if your hose is a tight fit I'd think you'd be fine without clamps but I'd hate to find out the hard way I was wrong. But without restriction blocking the holes in the stone the co2 shouldn't create back pressure behind the stone and blow it off but again I don't think I'd take the chance. SS worm clamp soak in a bowl of starsan is how I'd go about it. Just my .02

 

[LBussy]

Here is one

I just don't see the need for this type of product. For me it's a solution to a problem that doesn't exist. To each their own though.

Thank you.

I've been making sparkling waters with various dissolved minerals and it's taken longer than a few days to get the minerals dissolved because it takes more than a few days to get CO2 dissolved ... the equilibrium thing. I wanted to try a stone but reaching my hand in there to pull a tube off the gas line seemed a bad idea.

It might work for me ... admittedly it's a solution many folks probably would not need.

 

[Gavin C]

Thank you.

I wanted to try a stone but reaching my hand in there to pull a tube off the gas line seemed a bad idea.

.

You wouldn't need to remove the tube. All you need to do once equilibrium is reached is to disconnect the gas QD from the carbonation post on the lid and place it on the gas post as normal.

If you wanted the carbonation lid for another keg you could easily switch it out for a regular lid. Quick and easy. No worries.

 

[LBussy]

You wouldn't need to remove the tube. All you need to do once equilibrium is reached is to disconnect the gas QD from the carbonation post on the lid and place it on the gas post as normal.

If you wanted the carbonation lid for another keg you could easily switch it out for a regular lid. Quick and easy. No worries.

Right - this addresses my concern. If I did not have the "extra" gas QD for the diffuser I'd have to figure something else out. I was more saying this was a solution for a problem I saw/had with using a diffuser.

 

[ZmannR2]

Yes I get that, but doesn't flow come to a crawl once the keg pressurizes? Co2 can only flow as fast as it can be absorbed. It's not like a fish tank that vents to the atmosphere. What I can't get my head around is, with less flow = less bubbles. It could be the word FASTER. With the set and forget method, if it takes 3 weeks to fully carb, will it carb in 1 week or will it take 20 days? 1 week is faster 20 days not much.

Thank You
PapaO

You use a force carving method that takes 3 weeks? Dang man. I set my psi to 30 for 24 hours, then reduce to serving pressure for 48 hours and it's perfect after those 3 days.

 

[zam216]

I have the lid pictured in the first page and it is awesome. I can fully carb a beer in less than 3 days. Usually I transfer at night and set it to the wetting pressure at 4psi for an hour or 2. Then if I dont fall asleep I will increase it 1-2psi every 30minutes. If I fall asleep I usually increase before work. Again after work and a few times before bed and by the third day it is either at the desired pressure or right under it. I never carb without it now. The only problem I have is only having one lid so I have to depressurize and remove it to use it in another beer. Big thing to remember with these is the wetting pressure. Mine is 4 so if I want 11psi I need to start at 4psi and stop at 15 to get my desired level. Then when the beer is carbed I switch to the normal post and put it back at 11psi.

As for using clamps I do not use any. To clean it I usually dunk in PBW or boil it. I can take the tubing right off when boiling.

 

[LBussy]

How quickly a beer gets to serving carbonation levels depend on how much carbonation it has going into the keg. If you have a beer that's had a secondary (or even tertiary) fermentation that's lasted months or more in the case of some old ales, then it's going to take a much longer time to pick up that CO2. Beer coming out of the Primary after a couple weeks is going to have well over .5 atmospheres of CO2 already so it's not going to take much time at all.

Just as a baseline, if I take tap water and put 30 PSI on it (headspace, no carbonation stone, no shaking, it can take over 2 weeks in the fridge to get well carbonated.

 

[FenoMeno]

[QUOTEmUsuallydontn Big thing to remember with these is the wetting pressure. Mine is 4 so if I want 11psi I need to start at 4psi and stop at 15 to get my desired level. Then when the beer is carbed I switch to the normal post and put it back at 11psi.
[/QUOTE]

I can't find much info on "wetting pressure" , can you please explain?

Update: Just found this info...
"Before carbonating your first batch, you need to know the “wetting pressure” of your carbonation stone. This is the amount of pressure required for CO2 to push through the pores of the stone and begin making tiny bubbles. Each stone will have a different wetting pressure. To determine your wetting pressure, attach CO2 to the stone and put it in a bucket of water or sanitizer. Set it in sideways, as that is the orientation it will be in when carbonating your beer. Turn the pressure up slowly until a nice curtain of bubbles rises. Record that pressure. That is your wetting pressure. It is usually somewhere between 2-8 psi.

There is also hydrostatic pressure exerted on the stone by the beer in the tank. Every 28 inches of liquid exert 1 pound of pressure on the stone. So, measure from your carbonation stone to the liquid level on your sight glass to get the hydrostatic pressure."