FERRODAY Stainless Steel Carbonation Cap, Carbonator Cap with 5/16 Barb

When we got the carbonation lid for our corny keg, we were trying to figure out a way to provide carbonated water during the 2 days it would take to charge a fresh keg, and found these (same brand). The idea of being able to take a bog standard 2 liter bottle and charge carbonated water in it was, TBH, mind blowing, so I decided to give it a try, in the hopes it would give us a backstop while the keg recharged. The cap itself is cut on the sides allowing you to use a keg spanner to tighten it up, a really useful feature for us with physical disabilities that make grip an issue. It works so well! One thing that we did though was to get some liquid tubing, and a pair of micro porous stones (Ferroday again). We hooked the tube and stone up, in the hopes we could get the micro porous stone speed, and easier to store standing up while it charged. It works well in both cases. So for 3, 4 hours of charging, at 35psi, we get a 2 liter bottle of carbonated water. Any short of a time doesn't seem to work, but I don't know if this is a limitation of the carbonation cap or operator error, as I've seen YouTube videos that claim less than an hour to charge a bottle. I'd recommend this, both for charging a 2 liter bottle before going out, or as we're using it, to make sure we have standby fluids. If you're using this alone, rather than with the upgrades I mentioned, remember to lay the bottle on its side in the fridge for the tube to be inside the liquid.

If you are construction a home carbonation rig, this is the cap to get. Fits perfectly on a standard plastic soda or water bottle with a tight seal. Hight quality stainless steel and feels very rugged - not like the cheap plastic carbonator caps. Just screw on to the bottle attach the CO2 using a 5/16 coupling attached to the CO2 with a regulator and you are set. Great value for the money and saves me a ton of money allowing me to carbonate at home avoiding expensive systems like SodaStream.

I have had an original carbacap that I have been using for quite literally for 15ish years. They were made of nylon and work really really well, annoyingly I dropped the water bottle after it was carbonated with the cap still in place and the pressure bump from the drop (I carbonate to about 70#) was enough to make it start leaking co2. They havent been available for years and I saw the many good reviews for this and gave it a try, honestly I was pretty skeptical. I have tried a number of different caps over the years and have never found anything that works as well and that old one. They were bought out a number of years ago and the newer versions arent as good being made from a plastic resin, the original company name was liquid bread, if you ever spot one somewhere snap it up. I was delighted to find this has worked really well so far, Ive only carbonated a few times with it and Ill edit this if that changes but Im very happy with it so far. The only criticism I have is the outside shape, the round outside makes it slippery and not easy to get on and off, but that wont stop me from using it. Ill just be occasionally annoyed when I do, but Im easily annoyed anyway...lol

I use these for two purposes (both with a 10lb CO2 tank). 1) I buy soda in 2L bottles because on sale it is usually a lot cheaper per oz. A 2L bottle fills up four 500 ml bottles perfectly and I just squeeze out the air and tighten the cap and fill it up with 30psi of CO2. Far less plastic being used and less money being spent over the years. 2) Making my own seltzer water by attaching the inner barb in this cap to the tube connected to this stone: https://smile.amazon.com/gp/product/B091C5Y6L9 and squeezing out the air, tightening the cap and attaching the CO2 to this cap and shaking away. There is a plastic version of this that I tried because this is a bit heavy, making the bottle top heavy, but that cap only works on specific bottle, while this works on all bottles because they use easily replaceable washers. The plastic one costs twice as much as this metal one. The plastic one also does not like being fully attached to the CO2 hose as it wears away at the plastic over time. This metal one should not have that issue. One also would not have to worry about the plastic version rusting or leaving metal shavings behind which I have seen in other reviews but I have not yet experienced myself. Nor have I experiences any issues with sharp edges as I have seen in 1 of these reviews. Note that this appear to be 100% identical to the ones sold by KegCo, which I bought first, but these come with extra washers, which is a very nice touch.

Overall I'm impressed with this. The ball lock coupler works well, the cap fits a standard 2L PET soda bottle and doesn't leak under pressure, and it seems well built. I am able to use it to carbonate water in a 2L soda bottle. BUT the barb included is NOT 5/16", it is smaller. A 5/16" ID hose slips right off of it. This is not a new complaint (check the Q&A for this item). I really wish they'd update the product description to be accurate. Now I have to buy a smaller hose. EDIT: the barb is 1/4" and holds on to a 1/4" ID silicone hose well.

I bought this adapter to a soda keg valve only because I'd read that the "Carbonator" adapter, which I purchased and is plastic, got some bad reviews for durability. So far I am still using the plastic Carbonator, but I am so addicted to carbonated water that I thought it worth the 18 bucks to have this stainless carbonation cap as a reserve. One aspect that I'm curious and eager to try out is the nipple at the bottom of the cap. It receives a quarter inch hose that can be supended into the water while the pressure is applied. I think having the CO2 gas inserted directly into the water, might speed up the carbonation process because it will agitate the water. The blue Carbonator does not have this nipple so the gas is inserted into the bottle and remains at the top of the bottle for a long period of time; hence, the need to shake the bottle and diffuse the CO2, as many YouTubes instruct. I'm not sure if my theory is right here, so I will defer to anyone who knows more about the effect of the gas tube being suspended into the water. Revised: I threw out the plastic blue Carbonator cap and have been using this stainless steel one. It is much better. It is threaded with greater accuracy than the plastic one. The steel threads merge with the plastic Pet bottle threads very smoothly. The nipple at the base of the cap is useful: I attached a six inch plastic hose that allows the gas to be inserted directly into the water, the same as the design of the otherwise flawed Sodastream design (the flaw in Sodastream is the gasket seal between bottle and machine is faulty). This stainless steel cap seems pricey to me, but I'm sixty five years old and everything seems to expensively priced to me.

I have been using this for a few weeks now and enjoy making my seltzer water. I have a CO2 canister and set it to 40psi. I put a couple teaspoons of lime juice in a 2 liter bottle and fill it with refrigerated filtered water to about 3 inches from the top. I squeeze the bottle to get the water level to the top and screw on this stainless steel cap nice and tight. Then I use the CO2 ball valve connector that I normally use for my beer keg and pop it on. In a second the bottle is filled with CO2. Then I give the bottle a good shake for about 30 seconds or until I can feel it go soft. Then pump it up again. Shake again, and one more top off with CO2, one last good shake, and then I pour it into 3 18 oz glass juice bottles for storage. After reading more about issues of reusing 2 liter bottles and leaching chemicals, I feel better with storage in the glass bottles. I'm not too worried about the 2 minutes the water is in the 2 liter bottle to carbonate. I find the glass bottles, when filled to the top, hold a satisfactory amount of carbonation and 18 oz is a good amount to open at one time.

This cap has worked very well for me. I do have to report there was a small learning curve. I use the cap mostly on 1 L Smartwater bottles with CO2 at about 40 psi. I initially tried screwing on the cap too tight and it is possible to screw it on so tight that the vinyl gasket inside folds in and jumps into the neck of the water bottle rather than sealing onto the top of the lip. The cap will then leak. Since doing this a couple of times initially I now screw the cap on to make contact and then just some more to get a good seal and it has been perfect. I have left it in the refrigerator on an opened partially consumed and recapped bottle of carbonated water and came back a week later from vacation and the bottle still had pressure in it on removing the cap and the water was still carbonated. I also just unscrewed and removed the small filling tube on the bottle side to make it easier to clean and it it is not needed. I rarely clean it unless carbonating something other than filtered water. I have not had any o-ring problems using it 3 months so far.