Introduction: Simple, Cheap, CO2 Regulator

Picture of Simple, Cheap, CO2 Regulator

This simple CO2 regulator is used to slowly release CO2 gases from the fermentation process of wine or beer using water and a few parts that can be found quite easily. It works by allowing CO2 to get out of the fermenter without permitting oxygen to enter. If oxygen was to get into the fermenter, it would stop the yeast from making ethanol alcohol.

Step 1: Gather the Parts.

Parts that you will need:
-One Cork
-3 inches of 3/8 inch hose
-Hot glue or other sealant
-A water bottle
-Clear film canister (usually available at any place that develops photos, ask for one)

Tools that will come in handy:
-Drill with 3/8 inch and 1/2 inch drill bits
-Hack saw
-Bench vice
-Belt sander/metal file/sandpaper

Step 2: Drilling and Fitting

Picture of Drilling and Fitting

First drill the 1/2 inch hole in the exact center of the bottom of the film canister. It should have a little dimple where the tip of your drill bit will sit nicely. Next, drill a 3/8 inch hole through the clamp. A bench vice helps. Once the holes are drilled, fit your tubing through the hole in the cork. You will need to calibrate and trim the tube, but we will get to that later. Next force the cork into the 1/2 inch hole in the bottom of the film canister a bit more than 1/4 an inch. After you these parts put together, you will need to seal the cork into the canister. I used hot glue but other sealants should work.

Step 3: Constucting the Cap Fixture

Picture of Constucting the Cap Fixture

Now we need to construct the part that will act as the one way valve. You will need to sand down the cap to get rid of the lines or grip. To do this, leave the cap on the bottle and start sanding away. A belt sander would be very useful but if you do not have access to one of these you can sand it or file it down. You need to make sure that there is enough room between the cap and the sides of the canister. If it is an air-tight seal, it will not work properly. I just took the cap off and dropped it in and kept testing it. After you get it shaved down enough, screw the cap on tightly, remove that little ring of plastic, and cut the bottle right above the lip on the bottle. If you have no idea what I am talking about check out the picture. You will also need to sand off the rough edges.

Step 4: Putting It All Together and Calibrating

Picture of Putting It All Together and Calibrating
Lastly, you will need to punch a small hole in the cap in order to let out the gases. To calibrate your regulator you will need to adjust your tubing. Make sure the tube is nice and straight and protrudes about an inch into the canister. Fill it up with water to the top of the hosing and drop in the cap part you just made. Push down until the gas is released and some water comes out of the bottom, lowering the cap to a bit more than halfway. Pop on the cap and SLOWLY blow into it. If you blow to hard the cap will just stick to the top. You just have to slightly exhale to get it to work. I've also attached a video of it working on a jug of fermenting grape juice. Enjoy and I hope this was helpful!


Dandeman321 (author)2012-05-11

I've done that with a balloon. I've also done the tube in the water when the fermentation was going crazy and clogged the airlock.

Dandeman321 (author)2011-10-29

That's the spirit! yeaaah!

varrius (author)Dandeman3212012-02-15

Hello Mate, Living in the jungles of darkest Thailand we have no brewing shops here, Probably illegal anyhow. Maybe thats why there are rice beer and spirit brewing facilities hidden away all over!
Anyhow, I made an airlock from a piece of clear plastic tubing with a loop in it, secured by a cable tie, then glue gunned into the cao or lid of my fermenting vessel and then a piece of cotton wool in the top. As its so bloody hot here I sometimes use a drop of steralising fluid in the airlock water.

Enjoying the comments by the way.

sdphoto35 (author)2012-02-07

WARNING!!!!!!! I have a degree in photography and leaned the chemical components in film and you never, never, never ever want to use film containers to store food ,come in contact with food, or pills. depending on the company and type of film you could slowly be ingesting silver "cyanide" and the other chemicals are nun to friendly either. use only for objects you will handle but never come in contact with food or your mouth or eyes!

Silver cyanide is mainly used in the developing of film but the canters get reused over and over. when I worked in the photo department at walgreens we would ship them back and now that film is going out of style less and less is made and the containers get reused over and over this is not a food quality plastic either which can contain led.

Please don't tell me "well I have been using it and I am still fine" many of a photographer has had large health problems down the line from the chemicals we used to use and we didn't drink them either so for your safety please find another container to use other than film canisters

Dandeman321 (author)sdphoto352012-02-08

But you're not drinking beer out of this. It just creates an airlock to let CO2 out and keep oxygen from getting in. It doesn't come in contact with the beer/fermenting liquid.

nitehawk86 (author)2011-07-10

This is not a regulator but a waterlock. It does keep oxygen out of the container, but it does nothing to hold pressure in as a real regulator does. But there is no use in making a waterlock. They cost less than a dollar at homebrew stores.

However I do like the idea of reusing a cork and drilling it out to accept a waterlock. Rubber corks are always better and cheap, but sometimes you just don't have one on hand to fit the neck of the container you want to use.

Big jermini (author)2010-09-13

great tut! i have exactly those parts! was looking for somthing simple without the rubery/latex taste.
Also i have builders hotglue( the yelllow kind that you see in electronics that give even a soldering iron a hard time to melt).

i know the bad replies were old, but let me say this. The point of this ible is for the quick emergency "i have those parts!" times. This goes for all 'ibls...

1) you are a moron to think he expected anyone to go and buy the required materials. Why would you if its going to be more than pro price?
2) This works well for your first batch or even a "oh crap my airlock broke and ebay is my only option!" moments. If you dont feel comfortable reusing this then dont.
3) lets see your diy project? is it perfect? does it meet all saftey/health department/fcc/fda/rca/att/ymca requirements? i diddn't think so. its diy. it never will. stop being baby and crying. girly men.
4) this is an advanced method of control compared to what most of our ancestors used. they lived. oh right some out there have to try and control every single cell of bacteria they find. problem with that is we have more diseases now and are less immune to them because of our so called "sanitized lifestyle" I ate mud pies my sister made me. i see parents that freek and hose down their kid then give them an antibacterial bath when ever their kids touch dirt. a little germs wont hurt anyone. unless you have aids...

Volectorus (author)2010-08-08

nice Instructable, it gives me somthing to make soon. yay. its a shame that peep on here are giving you a hard time. it is a good design to make out of stuff laying around the house! thats the point.... its a home brew...

Dandeman321 (author)Volectorus2010-08-08

Yeah :/ oh well. They do make a good point about it not being sterile however. And you can get them for really cheap at brew stores so you don't really save a lot of money. I basically made it to save me a trip.

awraven13 (author)2009-12-06

Though this is a resourceful design from common household items, the device is an airlock or fermentation lock not a co2 regulator. 

biggy smalls (author)2009-09-15

personally i always use a new cork without any modifications, one that is not meant to seal in liquids. the pressure inside the bottle forces co2 out but does not allow o2 in. cheap and easy. no work required.

trailgrind (author)2008-09-20

I've brewed beer, made wine, and even moonshine. In addition, I have spent time learning about the history of each. While there are flaws in this method, exactly what do you all think people did before the time of plastics and modern sterilizing chemicals? Wine has been made for thousands of years. I commend Dandeman for his efforts even though I personally use cheap, mass-produced airlocks myself. As for the cardinal rule of Sterilize, have you ever heard of Lambic beer, originally fermented in open vats so that the local native yeasts could provide a wonderful citrus character into the beer. In general, some people need to do some research before criticizing the people that put instructables up. If you don't like what someone else puts up, do your own instructible of what you consider to the the "right" way, otherwise, please be quiet.

Dandeman321 (author)trailgrind2008-09-22

Thank you for the nice comment! I was so discouraged when I first made this, no nice words were said... thanks for the defense.

trailgrind (author)Dandeman3212008-09-22

No problem. If you wanted to improve the execution you could use a rubber stopper with a piece of hard tubing then then drill a slightly smaller hole than the tube in the bottom of the film cannister then push the tube in. that might be watertight, then you could add just a little silicone caulking on the outside where the tube contacts the canister. That could all easily be dipped in bleach water with no ill effects. That would solve all sterilization problems. Good luck, try making some mead some time.

Dandeman321 (author)trailgrind2008-09-24

Do you have any good recipes? Any sites with them on there??? I was actually thinking about making some for the fall with my roommates!

trailgrind (author)Dandeman3212008-09-24

I actually tend to just wing it with most of the wine I make. With Mead you need to make sure you add adequate yeast nutrient and that the acidity and specific gravity are ok. There is some variability because honey can be very different depending on region and blending, a mead made from orange blossom honey will have a much different flavor than one made from clover honey. The last batch I made I just added some citrus juice to get the correct acidity but you can choose to manipulate acidity with other juices, or acid blends for winemaking. In addition yeast choice will greatly influence character and flavor of your final product with some yeasts imparting citrus flavors and the natural characteristics of some yeast resulting from lower alcohol tolerance that will influence whether you have a sweet or dry mead. Other considerations include whether or not you want to make a carbonated version and/or whether you want more of a beer style or more of a wine (again, more yeast choices). My advice is to choose a yeast that is hearty and then just have some fun. Make small batches and experiment. That way if you land up with a failed batch it hasn't cost you as much, since the amount of honey used to produce mead can make failures costly (i've made batches as small as 2 liters). Just write down what you do with each batch so if you come up with a combination that you really like, you can replicate it at a later time. In addition if you land up with a batch that doesn't seem to have enough flavor you can do a freezer method concentration, where you freeze what you have then once solid pull it out of the freezer and invert it so you can separate the frozen water from the alcohol and flavor (about an hour of drip time). You'll land up with higher alcohol content and concentrated flavor but will never be able to reach 50% by this method, probably a max around 20% alcohol(this does not count as distillation so don't worry about the legality, so long as you don't make more than 500 gallons per year).
Here are two possible resources. Have fun!!!

bob.smitty (author)trailgrind2008-12-24

While extracting alcohol by freezing is not technically distilling, it is still illegal in most states in the US. Here's a quick, small and simple mead recipe (called by the knowing metheglin, which is just a mead with spices and/or fruits added) that you can make in a couple of hours from start to finish (not including fermenting time). If you mess it up, you're not out a lot, since it's only a gallon: 1 Gallon Water 1 Quart clover honey 1 Medium lemon 12 Cloves (about a teaspon) 1 cup breakfast tea Champagne yeast. Boil the water and add the honey; take from the heat and stir well. Add zest and juice of the lemon, the closes and the tea.Let it cool. put into a gallon glas jug and add the yeast. Shake a bit and put an airlock on the bottle. Ferment for two weeks, then bottle. Cap or cork the bottles and let sit at room temperature for two weeks. You can refrigerate then. You can drink it right away, but it will get better with two or three months of rest.

bob.smitty (author)bob.smitty2008-12-24

Sorry I forgot; this is not my recipe. I collected it from the usenet many moons ago when I first got interested, and it's good enough to come do again... and again... :) You can add a stick of cinnamon to it, but I prefer it without. It's great to do with beginners or with friends that don't brew, and since I almost always have some of this around, so when we're done with the washing I give them a bottle to take home - I believe in instant gratification and happy friends. I normally bottle this in brown or green wine bottles with natural corks.

Dandeman321 (author)bob.smitty2008-12-26

Thanks! That recipe sounds delicious. I may have to try it. I have just one bottle of my last mead left. I have some blueberry kiwi wine that is ready to be racked and I just bottled up my strawberry wine!

Dandeman321 (author)trailgrind2008-09-25

Damn that sounds like it can get complicated. I bought some wine yeast last year and tried to make some hard cider. I let it ferment for more than a month and it made very little CO2. You could not taste any alcohol in it either... My roommates and I were thinking about making some this year though so maybe we'll try some mead! Thanks for the links!

trailgrind (author)Dandeman3212008-09-25

Where you probably went wrong with the cider is what kind of cider you used. You have to make sure that you get unpastuerized cider that does not have preservatives in it. You have to be very careful to make sure that any juice you use never has preservatives, and those chemicals are meant prevent yeast and other microorganisms from growing in the juice. The big problem with cider is that in recent years they have begun to require that it be pasteurized and preservatives added. It is still possible to find it without, but you have to look a little more. Another problem is with the definition of CIDER, in the states it generally means an un-refined apple juice, which is not the same as the cider used for making "hard cider". Hard cider is made from a more purified version of juice than the american definition of cider. It is totally possible to make a very tasty alcoholic beverage from cider but it won't be the same as the hard cider you buy. In addition, if you can get unpastuerized cider, you can actually make a alcoholic beverage without adding additional yeast, cause yeast grows on the apples and when the apples are pressed for the cider, the yeast get into the juice. In that case I would put an airlock on a bottle, fill it with the cider and put it in the fridge to ferment at a lower temperature and for a longer time. It lands up being quite tasty. You're right, wine, beer, mead, and spirits production can become very complicated, but if you learn the fundamentals, and follow the basics, then you can have a lot of fun. A really good book for learning about making beer is THE COMPLETE JOY OF HOME BREWING. There are books on making wines, beers, ciders, and meads, so you can buy them or probably even get them thru the local library. It's worth the time, plus a lot of them have recipes in too.

Dandeman321 (author)trailgrind2008-09-25

Thank you! Yeah, that all makes sense about the cider. Is there a minimal time I have to ferment and rack the mead? I really don't think I could wait 5 months to try it out!!!

trailgrind (author)Dandeman3212008-09-25

well, that depends on what style mead you want to make (alcohol content similar to beer or wine), the yeast you use (some yeasts are faster fermenters), and what the temperature is. technically you can drink wine or mead anytime after the primary fermentation, the flavor will be different at that point when compared with if you rack it and let it age for a year. i would say the absolute minimal amount of time from mixing all the ingredients together to actually drinking would be about 1-1.5 months. However at that point the flavor will probably be a little harsh compared to aged. I believe with aging there is a decrease in some of the more volatile compounds that would influence flavor such as ketones which would be more plentiful after fermentation of only a month. Just keep in mind that most of the better wine and spirits that we drink are aged for good reason. The vessels in which the aging occurs can also greatly influence flavor, along with the addition of spices and herbs during aging. Take bourbon or scotch for example, aging in a oak barrel versus an oak barrel that has been scorched inside will result in different flavors that may not be immediately apparent to the layperson but would be like night and day for the connoisseur. When just learning to make wine, etc. you really are just at the starting point of understanding the complexities of flavors imparted by the choices you make during the process. A person could devote their entire life to the process and still not understand all the variables. In my opinion the best way to really understand these things is to not be afraid and experiment and have fun. There are a lot of wine snobs out there who can tell you lots about how bad they think a wine is, but they couldn't tell you the first thing about what processes caused it and they surely can't tell you how to correct it, so if in your explorations you find something that you enjoy that a wine snob thinks is terrible, forget them cause they couldn't do any better and would likely do much worse if they tried. Like i've already said, HAVE FUN!

Tarps (author)2008-09-26

Nice airlock! I think if I made it, I would just make the tube come up above the water level, then curve it back down so that the end is below the water level. That should let the gas bubble out. I often just stretch a balloon or condom over the fermenter opening, though. In general, I am way less concerned with sanitation than most people. I have made successful wine with only a piece of cloth stretched over a jar mouth. I don't even add bought yeast anymore. Wild yeast clings to the skin of most sweet fruit. You can see it as a dusty film on grapes, plums, etc. I just dunk some fruit in the mash to introduce the yeast. I don't even heat the water anymore. I think that as long as the yeast gets a foothold before the mold does, you're good to go. I like this approach as opposed to trying to control everything to produce desired results. The book "Wild Fermentation" has lots of great recipes and interesting info.

Dandeman321 (author)Tarps2008-09-26


melonbomb (author)2008-04-11

this seems like a terrible design: 1.hard to sterilise much labor due to bad design. just get your self a length of tubing, bend into an oval with the two ends facing oposing directions and secure with zip tie. fill bottom of the oval with a cheap spirit/water and be done. to sterilise just boil or soak in sterilising agent. a meter of tubing should run you £1.50 and will probably make 3 or 4 airlocks, if you dont have zip ties hanging arond your house you must be be an alien. .

Jwoody69 (author)melonbomb2008-09-10

First off I think your design is ingenius even if it is fragile. Good job! You are very creative. I have seen relatively cheap CO2 regulators or Beer Regulators for about $29 at this site would something like this work for your homebrew setup? I think it might be a kegerator setup.

Dandeman321 (author)Jwoody692008-09-10

Thank you! I really don't have a homebrew set up. My dad used to make beer and I was just fermenting some grape juice. I just needed something that fit inside a wine bottle's opening and could regulate the C02. I Just used a balloon in the end :/

Dandeman321 (author)melonbomb2008-04-11

Thank you. This has already been said to be a horrible design. I know. I just kept it up because a mod encouraged me to do so.

chuckr44 (author)2007-09-20

Does a typical grocery store (actually mine is the huge Meijer store) carry airlocks? They only carry canning supplies in the fall. If not, what type of stores would carry airlocks? It's not like we have any "wine making" stores here in Michigan.

gerrrtrudicus (author)chuckr442008-01-07

you do have wine making beer making stores in michigan. have you consulted a phonebook? Google?

K. No need to be a smartass.

gerrrtrudicus (author)chuckr442008-01-07

i did a google search and foun this

Dandeman321 (author)chuckr442007-09-20

You're probably going to have to buy one online unless you can find a wine/beer making shop around you.

Dandeman321 (author)2007-05-09

Easy to sterilize? drop it in boiling water for a few seconds.

trebuchet03 (author)Dandeman3212007-05-09

If not by boiling... Hot water and iodine - just like a hospital could ;) Yeah, you can buy them already made for pretty cheap... But where's the DIY spirit and fun in that? :p

xrobevansx (author)trebuchet032007-05-10

Again- Not to sound like a party-pooper (of course I love instructables) but we have no idea how these plastics/adhesive will react to iodine or any other sterilizing agent. Store-bought airlocks are made for this purpose.

As fun as it it would be to make your own tires for a car, I'd say the same thing: stick to the professionally made ones.

Homebrew beer has one MAJOR rule: clean and sterilize. That's all I'm saying.

I respect the spirit of the DIY here, it's just *I* wouldn't use it to brew beer or wine.

beanblog (author)xrobevansx2007-08-16

He's right. I'd never use this in my own brews.

Dandeman321 (author)trebuchet032007-05-10

That's right! I just had the stuff laying around so I figured why not.

climber_geek (author)Dandeman3212007-05-10

Because it is very porous, A used wine cork is great at harboring bacteria and is not easy to sterilize. How do you know that the boiling water is penetrating all the pores? don't. Besides, the glue would likely fail at those temps. The best home-made airlock is what brewers call a blow-off tube. You use 3/8" or similar poly tubing. You cut a hole in top of fermenter so that the tubing fits as tight as possible. You cut a length of tubing to run from the top of fermenter to a separate small vessel (a drinking glass will work). Sterilize the tubing. You then insert the tubing into the hole you cut atop your fermenter, then submerge the other end in water using the small vessel. Make sure the tube stays in the water by securing it to the vessel with tape. Then as a final precaution I seal the fermenter end by pouring hot wax around the seal to the fermenter (no bacteria is going to get in there). If not using wax I would want some sort of o-ring that fits the tube and cut-out opening perfectly. One bacterial cell getting in there could ruin the whole batch!

xrobevansx (author)Dandeman3212007-05-09

You really shouldn't boil those types of plastic, or the adhesive. Store-bought airlocks are one piece, and better quality plastics.

joshcube (author)2007-05-10

I mean this in the collaborative sense and not in a critical sense, but why not just use a balloon?

raelx (author)2007-05-10

As a home brewer for many years there are a lot of things I have made. But when I can buy this for $1 w/o the bacteria harboring cork it's a no brainer. Now if you wanted to make a drylock (low pressure ball check valve) that could be worth it. Also it should be noted that the purpose of an air lock is not to keep the O2 out of your fermenter but to keep bacteria laden air out. If clean air or oxygen were to get on top of your beer it would not stop fermentation.

tercero (author)2007-05-10

Wouldn't the hot glue melt if you dropped this into boiling water to sterilize it? I like the idea, but the practicality falls short.

meddler (author)2007-05-09

My great grand pa used to make apple wine, even had a few kegs explode, he would have loved this.

xrobevansx (author)meddler2007-05-09

I brew beer. There are two reasons I wouldn't use this: 1. Not easy to sterilize the entire airlock like a store-bought airlock. 2. A store bought airlock is like fifty cents, and this one would cost me time and what little it is in parts.

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