38mm Poly Seal Screw Caps (fits most 1/2 & 1 gallon jugs) [Bag of 12]

The more I use these caps, the more I appreciate them. At first I was disappointed because they are not the same height as the GTS caps. They seem to be doing the job despite this deficiency.My Kefer second ferments are coming out stellar.

I home brew kombucha and needed caps that sealed tightly to keep in carbonation during the 2nd ferment. In reading over the Q & A's for this product, one gentleman posted that these caps do not fit the new-style Dave's GT kombucha bottles. The new bottles have a slightly different screw-thread configuration versus the previous style bottles. You can tell if you have the new-style bottles as now the "GT" is a raised design on each plastic bottle cap. (The older bottles had a smooth plastic top - no embossing.) I respectfully disagree with his answer as I am very pleased with the fact these caps do work very well on the newer style GT bottles, and I've not had a problem with them doing the job I want them to do - and that is fitting so well that no carbonation leaks out.~~ OLDER style GT bottles: These caps fit perfectly. I've made a number of batches and the carbonation is totally contained - nothing can leak through the sides of these caps. I am now getting super fizzy (YUM!) kombucha.~~ NEW style GT bottles: Because the screw-threads are a little closer together and configured a bit differently than the previous style bottles, these poly-seal caps don't screw/tighten down as far as the caps that come with the bottles. HOWEVER, as long as you MAKE SURE to twist them on tight, making sure they are screwed down as far as they can go, they work great! I've had absolutely no loss of carbonation when using these on the new style bottles. The fizz factor is just the same as using these caps on the old style bottles.So, I am very pleased and happy I tried them, as I have more of the new style bottles on hand than the old style.**Remember: no matter what GT bottle you're using ... make sure to really tighten the caps after filling. You should then have great success with your 2nd ferment (if all other steps in the 2nd fermenting process are done properly).UPDATE: 4/27/2017: After 9-months of using the same caps on the newer bottles I think I've had a good amount of experience with them. I still say these caps work well on the newer thread-style GT bottles almost all the time. Now you will find that the caps seem to not screw all the way down - this is due to the thread design. And after the 2nd fermentation is done, I will admit that sometimes a bottle isn't as fizzy as another. But I still have a few of the original thread-design bottles and sometimes one of those isn't as fizzy as the others (I put them in the frig after the 2nd brew as I make a number of bottles at a time). One kombucha brew can sometimes be more or less carbonated than the next as many "kombucha brewing experts" mention. But no matter what, I have always had some level of carbonation in all bottles with the newer thread-style after the 2nd brew.**What I have found is what other's have posted on other sites ... it can help to turn the cap gently to the left to get it seated on the thread, and then screw it on tight.But in a perfect world, I do wish a cap manufacturer would make caps that really fit the newer GT bottles. But the "GT" initials are embossed right into the glass on the bottom, so maybe Dave (Dave's GT) does have an exclusive on the thread design, and cap manufacturers aren't interested in catering to a very small percentage of those who are kombucha home brewers.

Got these for some old 1 Gallon bottles I found down on the farm. I was making a 1-gallon batch of Hard Apple Cider. I thought fermentation was done, so I decided to back sweeten the Cider in one of the 1-gallon jugs. Checked the first week to make sure there was no off gassing and things looked normal. A few weeks later the whole bottle exploded. (Had it in a bomb proof metal milk jug) The cap was still on the top after the explosion. So, I can say that 100% no air escaped this cap. Lesson learned as this was my first attempt at a Cider. Just need to make sure all yeast is dead before I use the gallon jugs for storage.

So far so good, I am leaving 4 stars until I have a chance to further test these caps out by bottling kombuncha with them. These caps are in my opinion intended to seal growlers for beer, but I will be using them for kombucha. I have checked these caps on my growlers and they do fit very well. My application is to use them for the 2nd fermentation of kombucha tea, I plan on updating this review once I can say for sure how well they hold the pressure generated by the release of carbon dioxide and ultimately the carbonation of the kombuncha. I will be comparing them on growlers as well as GT's Kombucha (new style) bottles and another brand bottle with a similar thread to GT's old style bottles. I have noticed a lot a mix reviews of wither or not these caps work on the new style GT's bottles, as they have a different thread. At this point I know for sure that they do fit the new style bottles without ruining the thread on the caps. I hope that the seal is able to hold enough pressure to carbonate the kombucha.I am attaching imaging of the style of bottles I will be checking these caps on, as well as imagines of the the caps I you can compare them against. Obviously the black cap is the one being reviewed. The other two caps are a generic growler style cap and a GT's Kombucha new style cap.

These are great for my 1 gallon jugs. I have glass jugs that range from 25 years old to brand new and these fit them all flawlessly. No leakage even with a little internal pressure.

Just what I needed.

Have met and exceeded my expectations.