Poor man's CO2 purger...dry ice

[7Enigma]

So I made the mistake of drinking a glass of Mountain Dew when I woke up last night at 2am.....and then sat in bed trying to fall asleep for the next 2 hours. During this time I had quite a bit on my mind. What I wanted to eat for dinner, work the next day, the primary fermentation in the basement...you get the idea.

So since I'll be transferring from primary to secondary in the next couple days, and since I made the mistake of boiling off quite a bit of water during wort-making, and probably didn't measure properly, I've been concerned about oxidation if my volume is low when racking to secondary.

All these fancy pressurized CO2 purging systems sound great, but I'm a hobo! I needed a cheap, effective way of purging my secondary of air so my precious beer has a shot at tasting good.

I came up with a very simple (and cheap) way of purging the secondary in a sterile manner. Now we all know ice and dry ice is not a clean substance, both can harbor pathogens that can ruin the beer, with dry ice having the added "benefit" of normally containing lubricants and such during the production of the dry ice. These obviously would not be great in the beer, and so we need a way of not allowing the dry ice to contact the insides of the secondary.

I had thought of using a small diameter aluminum can (like from those pineapple juice individual cans) and lowering it down full of dry ice to slowly evaporate and displace the air. The problem is of course sterlizing everything going into the secondary, and the slight but real chance of the gas carrying with it spores/etc. that could contaminate the beer.

So I pondered this at 3am and realized the best way would be "racking" the CO2 produced from the evaporation of the dry ice INTO the secondary the same way you would rack beer from the primary. So here's my setup (I'll have to get a picture at a later time so its easier to understand):

- small bottle to house the dry ice. This doesn't need to be sterile but it can't hurt

-stopper with WIDE hole in it that fits snugly on the bottle with the dry ice. I cannot stress enough that this hole needs to be wide. I did some testing with small diameter hoses and it creates an explosion hazard similarly to a clogged airlock. Depending on how much (or if) water is used to speed up the evaporation of the CO2 frost can develop in the stopper and limit/stop the flow of CO2. You've now got a bottle bomb that if allowed to build pressure could be dangerous. I make sure to put the stopper on snugly but loose enough so that IT will be the failure point and just shoot out of the top (Idiot Disclaimer: Don't stick your eye up to the stopper at any point :cross: )

- Sterilized DRY tubing that fits TIGHTLY inside this stopper. You want a perfect seal to make sure all the CO2 being produced is traveling through the tubing without leaks since there will be some backpressure from the....

-0.2um (micron) particulate air filter. A 0.45 or 1um filter would probably work just as well but the smaller the better to prevent spores and such from making it through the line. You should be able to find one of these at most larger hardware stores. If you can get them with a barbed end that's the way to go since you can just slip it onto the tubing.


OK, with your parts in hand cut the tubing about 2/3rd's on one end:

------ X --------------------------

Wonderful drawing I know. The ---- represent the tubing and the X represents the air filter. Many filters have an arrow ---> on them showing the direction of air flow. Put the filter inline so that the arrow is pointing TOWARDS the longer piece of tubing. The long piece of tubing is what is going to be INSIDE your secondary container, while the short piece will be connected to the stopper on the dry ice bottle.

So here's what you have now:


O==O-----X-----------------secondary


where the O==O is your dry ice bottle and the secondary is duh!

The only portion of this setup that actually needs to be sterile is the section of tubing from the air filter (X) to the secondary.

So now you go to your local supermarket and get a small hunk of dry ice (only need an icecube size piece since gaseous CO2 is much less dense than a block of it). Put it in a styrofoam cup and then another one on top (like 2 cups stacked together). You don't want anything sealed due to the pressure buildup, but want to insulate it as well as possible. With this setup the dry ice should stay relatively the same size over several hours. You can always get a larger chunk if you know it will be a while before use, but PLEASE STORE IN A WELL VENTILATED AREA!

When you're ready to purge simply place a piece of the dry ice in the dry ice bottle, add a small amount of water to get the dry ice evaporating quickly and put the stopper on. The CO2 produced will now begin to displace the air in the dry ice bottle, get filtered of any potential beer-spoiling baddies, and replace the air in the secondary with pure sterile CO2. Let it do its thing for a while (10-20 minutes as long as its producing CO2 at a good rate), and then simply rack your beer.

So this is a quick, easy, and cheap way to purge your secondary of air prior to racking letting us cheap-o's have the same sense of security as those with the compressed CO2 bottles and fancy equipment.

Hope this helps,

justin

 

[FlyingHorse]

May be it's just me, but this doesn't seem easy, quick, or necessarily cheap.

Much easier to simply set up a closed primary-to-secondary racking system, and let the natural CO2 from primary fermentation purge your secondary.

EDIT: like johnsma describes here Wouldn't be hard to rig up the same sort of setup with carboys, or maybe even a bucket and a carboy.

 

[Revvy]

I think you're overworrying about something (I'm not sure if this is your first batch or not) that may or not be a problem....People have been carefull racking from primary to secondary with mostly no problems for decades (or else we wouldn't be doing it.) Like taking grav readings or any other thing that a new brewer will sweat about...If it would ruin the beer then we wouldn't be doing it....

If it's your first batch then RDWHAHB...Beer is a lot more forgiving than it seems....

I've racked from a primary bucket to carboy secondary countless times with no problem....When your auto siphon is submurged in your primary, and the bottom of your siphon hose remains at the bottom of your secondary then you are filling your secondary from bottom to top and will be pushing out any 02 along the way, plus the simple act of sticking the auto siphon in the primary is going to kick up some of the yeast and re rouse them, which is going to make them begin producing gas in the secondary almoust immediately....

BUT at the same time it's an intriguing idea, and I'd like to know how your experiment goes (and pleast take pics). Experimentation is what makes this obsession twice as much fun!!!!

:rockin:

If you're really worried about it, like bike n brew said you can go for a closed system....Somewhere around here is a betterbottle diagram showing a closed system using their products....It may give you an idea...

EDIT Bike N brew just posted the diagram I was referring to...it uses the spigot system that can be put in the better bottles[/url]

(b-n-b- Great minds think alike!)

 

[raceskier]

Before I got my kegging setup and had a ready source of CO2, I just used my bike tire CO2 inflator: http://www.amazon.com/dp/B000AO9TQC/?tag=skimlinks_replacement-20
1 cartridge was good for purging the secondary. I just cut the valve out of an old tire tube and added a piece of vinyl hose on the end of it. I use a HEPA filter inline, but others have gotten away without that. You can also use it for a very portable keg pressurization setup, should you decide to start kegging.

 

[Bokonon]

Reading this gave me an idea. If you get a deep container, maybe a big cardboard box or chest freezer or something, that at least is taller than your secondary vessel. Then put the dry ice in something next to it and allow it to evaporate/sublimate over time it will displace all the oxygen in the box and when it reaches the height of the carboy/bucket it will flow over the edge and displace the oxygen in there.

Of course I think this is really overkill and probably not necessary.

 

[7Enigma]

May be it's just me, but this doesn't seem easy, quick, or necessarily cheap.

Much easier to simply set up a closed primary-to-secondary racking system, and let the natural CO2 from primary fermentation purge your secondary.

EDIT: like johnsma describes here Wouldn't be hard to rig up the same sort of setup with carboys, or maybe even a bucket and a carboy.

Total cost should be under $10 (probably closer to 5 if the filter is cheap). The only thing that actually costs some money is the air filter, the rest is free/very cheap. You can use a 20oz plastic soda bottle for the dry ice bottle, you could technically use a hole punched in a screw on cap (but I recommend against this for fear of clogging), otherwise a plastic stopper that you drilled a hole in for the tubing. Tubing you can just use normal siphon tubing.

What makes this so easy is that as mentioned the ONLY part that actually needs to be sterile is the section of tubing going into the secondary. The air filter will make sure the only thing going into the secondary is pure CO2.

I might be making it sound much more complicated than it actually is. Once I build it I'll take a picture next to the fermenter so its visual.

EDIT: Actually after looking at your link my dry ice purger is basically the A diagram, just using the CO2 from the dry ice instead of the yeast produced CO2. The only problem with that I see is you would need to either have it setup prior to primary fermentation starting (which is I assume how its designed to be used), or would need to hook it up while there was still active CO2 production. In my case I'm barely seeing more than a bubble or two a minute in the airlock of the primary and so I don't think it would displace enough air to actually be beneficial over just carefully siphoning to the secondary without splashing.

 

[7Enigma]

Reading this gave me an idea. If you get a deep container, maybe a big cardboard box or chest freezer or something, that at least is taller than your secondary vessel. Then put the dry ice in something next to it and allow it to evaporate/sublimate over time it will displace all the oxygen in the box and when it reaches the height of the carboy/bucket it will flow over the edge and displace the oxygen in there.

Of course I think this is really overkill and probably not necessary.

This is not a good idea. Allowing unfiltered air (be it O2 or CO2) is not a good practice when trying to prevent contamination. Again its very possible you'll never get a contaminated batch, but there's a reason we use an airlock and don't just keep the lid off. It's undue risk.

 

[Shonuff]

At 5-10 bucks everythime you transfer it would be cheaper to just buy a CO2 tank/reg after awhile.

 

[7Enigma]

At 5-10 bucks everythime you transfer it would be cheaper to just buy a CO2 tank/reg after awhile.

$5-10 is the one-time cost for the equipment, after that its just the piece of dry ice that is needed. And you could probably get that for free if you literally say I need a gumball-sized piece of dry ice (they normally sell them in large blocks).

 

[malkore]

I've never found a dry ice supplier in my area that sells less than 1-3lb blocks.

seems like a lot of work to fix a problem that really doesn't exist in the home brewery.

 

[david_42]

Let's see: nearest dry ice supply 35 miles one way, diesel $4.19/gal., Sprinter 26.8 mpg. $11/trip. 5 lb tank of CO2, $8 every two months.

I guess this works if you can walk over and get a chunk free.

 

[7Enigma]

Let's see: nearest dry ice supply 35 miles one way, diesel $4.19/gal., Sprinter 26.8 mpg. $11/trip. 5 lb tank of CO2, $8 every two months.

I guess this works if you can walk over and get a chunk free.

Wow! Our supermarket 2 blocks away has it for like a buck.

OK for you, take an old REAL fire extinguisher (SCUBA tank, not the crappy rolled steel with the liquid foam inside) and get a small pillowcase. Put the nozzle inside the pillowcase and make a tight seal near the top (to prevent escaping CO2). Shoot for 5-10 seconds and you get some nice pieces of dry ice.

Just kidding btw. This works but its not very economical.

 

[7Enigma]

OK everyone, here's the update with pics since I transferred from primary to secondary today.

Here is the business end. Simply a plastic bottle, a rubber stopper with a hole drilled in it (I used several bits of increasing size and moved the bit back and forth to slowly scrape away the rubber, took like 10 minutes), a barbed connector with fat end on one side and smaller end on the other (now that I look back on it this could have been omitted and just put the filter directly into the stopper <smacks forehead>), and the filter. To the end of this you put the sterile tubing.

So in this picture I've put the dry ice in, and added a shot of water. If I were to do this again I'd add 2 shots of water. It started to peter out while there was still some solid dry ice in there. If your not in a rush 1 shot is fine, but I had stuff to do (plant my hops!). After you add the water to the dry ice, keep the stopper off for a minute or so. The air needs to first be purged from the bottle. This air has quite a bit of moisture in it and is what can clog the stopper with frost causing it to pop off. This is the reason why a stopper is used, in case of overpressure the stopper simply pops off, no explosion hazard. Again the only thing that really needs to be sterile in this setup is the tubing AFTER the air filter, everything before will be filtered.

Here's a very scientific way of making sure there are no leaks and the CO2 is being produced by the dry ice. Pinch the tubing above the filter and hold for a couple seconds. When you let go listen for the rush of CO2 as it goes into the bottle. If you have active CO2 being produced and don't hear this rush you need to check for leaks. Spray some soapy water on the joints and look for bubbles. This is a really low pressure setup, so unless you've done a crappy job there won't be any leaks.

 

[7Enigma]

Here's a zoomed out view of the purging setup. I sprayed some isopropyl (rubbing) alcohol on the tubing that was to go inside the bottle. There is no need to have the tubing far into the bottle because the pure CO2 will drop right through the air and start displacing the air out of the mouth.

See the CO2 going into the bottle? Of course you don't, that's why people get carbon dioxide/monoxide poisoning. At least you can smell CO2....

In the background you can see the 6.5 primary. Kids this is why you should separate out your break material prior to fermenting. That's about a 2-3" layer of crud in a 6.5!

And here's the final product, quite tasty even at this point (though I appear to be a bit low so who knows how that affected the fermentation), and guaranteed to not have a single oz of air (well possibly, but there is definitely a large amount of CO2 in that head space):

Oh and to those that recommended the Oxyclean I thank you heartily! I had thought it would be difficult to get the caked on krausen layer off since with a carboy you really can't get inside. I used some oxyclean and a garden hose out back to fill it up and let it soak overnight. This morning its crystal clear on the walls, the caked stuff just fell right off.

Cheers!

 

[Yunus]

Thats a cool idea.
But how about this. I use a bike co2 pump that takes cartridges. Why not just attach a tube long enough to reach into the beer to the co2 pump (easily done with a simple 2 dollar bike valve) then run the tube through the center of a stopper (making sure its a good tight fit, electrical tape or teflon tape would probably do it). Then hold the stopper so its almost seated on the carboy. Discharge co2 displacing air and before the cartridge runs out you push the stopper down on the carboy. Then pull the tube out of the stopper and put your airlock on.

Yes there could be a very small amount of air that reenters in the 1-2 seconds that you pull that tube out vs having the airlock installed. But it would be very small and this would be a cheap solution that is easy and requires parts available at any bike shop and a plastic tube.

Innovator bike pump - $15
Bike valve - $2
Tubing - $1
cartridges - pack of 20 at walmart for around $9

If anyone is confused but interested I could take a picture of what the hell I'm talking about and post it if you like.

 

[Philip1993]

I have an easier solution. Siphon quietly....

 

[7Enigma]

Yes there could be a very small amount of air that reenters in the 1-2 seconds that you pull that tube out vs having the airlock installed. But it would be very small and this would be a cheap solution that is easy and requires parts available at any bike shop and a plastic tube.

Sounds like it would work fine. If you see in my picture I just have the tubing in the open mouth of the secondary. There is no need to have it sealed with an airlock or other. The CO2 is much denser than the air and will sink in the bottle pushing out the air. As long as you don't open the dry ice bottle (or in your case run out of CO2) you won't have to worry about any introduction of air because it will just rest in the bottle like if it were full of water.

And remember, we really only need a small amount of CO2 space in there for the beer to rest up against. It doesn't need to completely displace the air, but it won't hurt to purge it all (I figure if you set it up, why not purge the whole thing).

I think where this would really come in handy is either waiting a really long time to rack to secondary (say you forgot and fermentation is just about complete), but you still need to do a secondary (for instance to crash cool or lager). Without this method there is the chance (sure its slim) that it could oxidize if virtually no CO2 is produced/released. Here you will know there's no risk of ruining your beer.

After trying this out and realizing how easy it was I think I very well might use this with the bottling bucket (purge the bucket before transferring for bottling, and might just do a test with a couple bottles (you would need like 5 seconds per bottle to quickly purge the headspace). The only concern (and probably very minor) would be the CO2 dissolving back into the beer along with the priming sugar causing overpressure, but again I don't think this would happen since the headspace is so small.

Glad someone at least read the thread after all the picture posting (took me like an hour!).

 

[Yunus]

I love pictures. I'm still new at this and many times I read a thread and get confused by the terminology but then see it and it clicks in my brain.

For example

Single Infusion Mash followed by batch sparging. - These 2 steps have kept me from all-grain brewing for a while now. I read all about it but it seems so freaking complicated and scientific calculations were required and the moon must be in the correct phase and a mash tun without a circumfrance area of 2pieR would equate to skunk beer.

After seeing pictures - Put grains in cooler, add water. Wait. Fill bucket till it comes out clear. Dump back into cooler. Drain to brewpot. Add hotter water. Drain to brewpot.

Seriously, which one sounds more difficult. Pictures made it possible for me to understand.

Thanks for taking the time to add them.

 

[Old_Brewer]

I like your pictures. Have you tried using vinegar and baking soda to generate CO2?
Quite awhile ago I made a setup like yours, so I could pressurize a whiskey barrel & get the wine out of it. The barrel was low enough so that I could not siphon.

I just siphon & let the beer purge the air. There is also some out-gassing of the natural CO2 from the beer, enough to most likely displace the remaining air.

 

[Philip1993]

The only concern (and probably very minor) would be the CO2 dissolving back into the beer along with the priming sugar causing overpressure, but again I don't think this would happen since the headspace is so small.

While I love a good DIY gadget as much as the next guy, you are WAY overthinking this. A sealed keg pressurized at 10-12PSI takes 2-3 weeks to carbonate. A keg pressurized to 30psi takes 36 hours. There would be ZERO carbonation of the beer in your bottling bucket even if the headspace was 500cu.ft.

As for headspace; The headspace volume has no effect on gas absorption. The working factors are the exposed fluid surface area and temperature. So whether your bottling bucket has 5.1 gallons or 1.1 gallons, the rate of gas uptake remains the same.

 

[7Enigma]

While I love a good DIY gadget as much as the next guy, you are WAY overthinking this. A sealed keg pressurized at 10-12PSI takes 2-3 weeks to carbonate. A keg pressurized to 30psi takes 36 hours. There would be ZERO carbonation of the beer in your bottling bucket even if the headspace was 500cu.ft.

As for headspace; The headspace volume has no effect on gas absorption. The working factors are the exposed fluid surface area and temperature. So whether your bottling bucket has 5.1 gallons or 1.1 gallons, the rate of gas uptake remains the same.

I think you misunderstood my post. The purpose of both the purging of the bottling bucket and the possible use in bottling was to purge the air from both containers, not for carbonation. I made this originally for the purging of the secondary prior to transfer as I had read several people do this with pressurized CO2. It wasn't until after I realized what I was doing that this could also be used during racking to the bottling bucket and/or to purge the air out of the bottles prior to filling.

And while you are correct the RATE of uptake is not dependent on head space the ABSOLUTE uptake is very different. That 1.1 gallons with 3.9 gallons of pure CO2 headspace would be much more carbonated over time than the 5.1gallons with minimal CO2 headspace. The concern was adding the typical amount of priming sugar along with the CO2 uptake from the headspace possibly causing a gusher due to the extra CO2 that would equilibrate into the beer.

Sorry if I was unclear in my original post.

 

[Philip1993]

I think you misunderstood my post. The purpose of both the purging of the bottling bucket and the possible use in bottling was to purge the air from both containers, not for carbonation.

Perhaps I did. You said; "The only concern (and probably very minor) would be the CO2 dissolving back into the beer", which I took to mean you thought it worthy of concern. My point was that the probability of spontaneous carbonation in an open vessel (and subseqent bottle bombs) is zero.

And while you are correct the RATE of uptake is not dependent on head space the ABSOLUTE uptake is very different.

In open vessel (a bottling bucket), the headspace approaches infinity. Therefore, a change in volume from &#8734; to &#8734;+3.9 is negligible and the only items of importance are the rate and the time.

In a closed vessel at STP (a carbuoy, no CO2 production), the vapor pressure above the fluid will reach an equilibrium quickly and no more gases will be absorbed. If gases were being absorbed from a closed vessel, the pressure in the unoccupied space must drop, resulting in a backflow through the airlock. Since we know that at a steady temperature airlocks don't get sucked back (or even show observable differences in static pressure), it is also safe to say that gas absorption in a non-pressurized vessel is negligible.

That 1.1 gallons with 3.9 gallons of pure CO2 headspace would be much more carbonated over time than the 5.1gallons with minimal CO2 headspace.

Skipping all the physics, I believe that by searching this forum you will find that for any given T&P, the volume(s) of gas dissolved in a fluid under pressure are constant regardless of head space.

 

[7Enigma]

In a closed vessel at STP (a carbuoy, no CO2 production), the vapor pressure above the fluid will reach an equilibrium quickly and no more gases will be absorbed. If gases were being absorbed from a closed vessel, the pressure in the unoccupied space must drop, resulting in a backflow through the airlock. Since we know that at a steady temperature airlocks don't get sucked back (or even show observable differences in static pressure), it is also safe to say that gas absorption in a non-pressurized vessel is negligible.

Skipping all the physics, I believe that by searching this forum you will find that for any given T&P, the volume(s) of gas dissolved in a fluid under pressure are constant regardless of head space.

Other than a mechanically filtered beer, where would we ever have a brew that doesn't have some CO2 production from remaining yeast? Even a small amount of yeast activity creates a noticeable abount of CO2 production over time.

With that said the vapor pressure will not equilibrate quickly unless you are rocking the bottles back and forth for quite a while after capping. Passive diffusion rates are not fast. But our unit of time may be different (are we talking hours/days/weeks).

Gases that dissolve back into a liquid do not condense to liquid (thus lowering the pressure in the vessel and creating a vacuum), they merely displace some liquid. It's like having a bunch of ping pong balls in a bucket with quarters neatly layed on top. If I shake the bucket a lot of the quarters fall into the bucket, which raises the total height of the balls because the space is being occupied by the quarters. You aren't gaining or losing anything, just rearranging how they are in the bottle. If you were to take a highly carbonated beverage and put it in a tall skinny container and mark the liquid level, then put it under vacuum and could account exactly for the amount of liquid that would evaporate you would see a real decrease in volume of the "liquid" after degassing. You're removing those "quarters" from the ping pong balls, which is perceived as losing volume, when you're just really removing all the air in the liquid.

You are correct that at any given temp/pressure the amount of a particular gas that can dissolve is constant (lets use CO2 for example). This would be appropriate say if you had 3 gallons of headspace vs. 3.5 or something high enough where the smaller volume of headspace will max out the dissolved CO2 capacity of the liquid. But if you compare in your example a very large headspace to a very small headspace (3.9 gallons to minimal headspace), the odds are you will have more CO2 dissolved in the beer with 3.9 gallons of CO2 headspace because the absolute number of available CO2 molecules are going to saturate the beer, while the very small headspace beer won't be close to saturation.

 

[fishops]

Wouldn't it be quicker easier and cheaper just to sanitize a cheap soda siphon and zap a couple of 8 gram CO2 cartridges right into the carboy?

 

[Philip1993]

With that said the vapor pressure will not equilibrate quickly unless you are rocking the bottles back and forth for quite a while after capping. Passive diffusion rates are not fast. But our unit of time may be different (are we talking hours/days/weeks).

I'm confused, weren't we talking about bottling buckets and carbuoys?

Gases that dissolve back into a liquid do not condense to liquid (thus lowering the pressure in the vessel and creating a vacuum), they merely displace some liquid.

Not true. CO2 dissolves to form carbonix acid (H2CO3) and oxygen binds with other molecules in the wort (why oxidation is an issue) and with free H+ ions (in an acidic wort)

Then put it under vacuum and could account exactly for the amount of liquid that would evaporate you would see a real decrease in volume of the "liquid" after degassing.

That is true of an aerated fluid, and also because lowering the atmospheric pressure above the fluid lowers the vapor pressure causing evaportion and re-combination.

You are correct that at any given temp/pressure the amount of a particular gas that can dissolve is constant (lets use CO2 for example). This would be appropriate say if you had 3 gallons of headspace vs. 3.5 or something high enough where the smaller volume of headspace will max out the dissolved CO2 capacity of the liquid. But if you compare in your example a very large headspace to a very small headspace (3.9 gallons to minimal headspace), the odds are you will have more CO2 dissolved in the beer with 3.9 gallons of CO2 headspace

No odds to it. It simply doesn't happen that way. The effective volume of headspace presented by a 5# CO2 bottle attached to a keg is for all practical purposes infinite.