Guide to kombucha carbonation
“My kombucha isn’t fizzy enough…”
It’s a common issue a lot of homebrewers face. Here, I’ll
walk you through some tips to produce perfectly fizzy
Before we get started…
Carbonation usually only happens in a closed container.
Some brewers can sometimes get a good amount of
carbonation in their first fermentation vessels (which are
only covered by a cloth, so they’re not airtight). But to get
really good carbonation, most home brewers have to go
through a second fermentation (F2) process in a sealed
vessel (a bottle) in order to build carbonation.
Think of it like bottle conditioning a bottle of champagne. A bit of priming sugar is added to a bottle, where the yeasts in the liquid will eat the sugar to convert it into carbon dioxide. If you want more in-depth info about second fermentation, you can go here. But if you’ve already got that down and are looking for ways to get consistent carbonation, you’re in the right place.
What does “good carbonation” look/feel/taste like?
To me, good carbonation means the drink has a nice, bubbly mouthfeel that doesn’t go flat super fast. I want visible bubbles in the bottle when I open it or in the glass when I pour it. I want to be able to open it and drink it right out of the fridge, and have it be perfectly bubbly but not so fizzy to the point where it spills over. I don’t want to be left cleaning up a mess and wasting valuable kombucha every time I open a bottle.
Your preferences may very well be different than mine. Some people don’t want any carbonation, and that’s OK. You don’t need to go through F2 in order to drink kombucha. But if you do want fizz, read on...
Tips for good carbonation:
Before you bottle, stir the liquid in your brew vessel. Stir it well! Yeast has a tendency to settle down at the bottom of brew vessels, so if you don’t stir and you’re pouring your kombucha into bottles, some bottles may have too little yeast (if the bottle contains the un-stirred liquid from the top) and some bottles might have too much yeast (if the bottle contains liquid from the bottom). This is often why homebrewers experience a lot of carbonation variance between bottles even within the same batch! Make sure you’re evenly distributing and mixing your kombucha well before you pour it into bottles.
Use fresh fruit puree.
If you’re using fresh cut pieces of fruit and your bottles aren’t bubbly, the yeast may be having a hard time accessing the sugar in the fruit and eating it. If it can’t access enough sugar from the fruit, it can’t produce carbon dioxide. Therefore no fizz.
If you’re using store-bought juice and having problems, it might be because the juice has been pasteurized or contains some type of yeast-inhibiting ingredient/chemical that’s getting in the way of your kombucha fermentation.
You can read more about my flavoring tips here.
Use good-quality bottles with airtight caps. Bottles and caps play a big role in this. You want to make sure you have as airtight of a seal as possible on your bottles. I have a few different types of bottles that I’ve been able to use to get perfectly fizzy kombucha. But flip-top bottles* are a good bet. Check out my post on bottles and caps to find out more.
Dry your caps and bottle tops before sealing. By doing a quick wipe-down before you close it up, you’re making sure there aren’t any liquid/fruit particles that get lodged between the bottle and the cap. This’ll help ensure that you can get it as tight as possible.
Use a rubber gripper to seal tight. These basic rubber grippers help me close up my screw-top bottles better than I could do it by hand.
Don’t burp your bottles. I know this is controversial because a lot of homebrewers will insist that burping is part of their process. Burping is essentially just opening your bottles ever so slightly during the F2 process to release air or “excess pressure” in the bottle. I personally do not think it’s necessary once you’ve got your process nailed down. And I think that in a lot of cases, burping sabotages homebrewers who are trying hard to build carbonation. If you want more details on why I’m anti-burp and the rare instances when I do advise burping, you can read my post here.
Don’t get rid of brown yeasty things. Oftentimes, yeast can grow on your SCOBY and look like unappetizing, stringy, brown mucus. Many brewers like to “clean” their sSCOBYs to remove the odd-looking growths. But unless your SCOBY is completely covered in them, I say just leave them alone. That yeast is what helps build up carbonation. If you’re not getting good fizz, it may just be because you’re cleaning too much yeast out of your brew.
Take care of your SCOBY. A healthy SCOBY produces fizzy kombucha. If you want more info on SCOBY care, you can go here. But if you’re having fizz issues, think back to whether or not you’ve broken any of the “rules” of SCOBY care that I’ve listed out. Did your SCOBY come into contact with flavorings (whether they’re natural or not)? Did you store your SCOBY in the fridge or somewhere really cold for longer than a few hours? Did you purchase a SCOBY with a shady history? All of those things (and more) could contribute to you producing un-fizzy kombucha.
If the yeast-bacteria balance is thrown off by someone unintentionally harming their SCOBY, that could produce problems down the line over time. So if you’ve tried everything possible to create fizz and you’re doing everything “right” — it may not be you. It might be your SCOBY. You may have a weak SCOBY or a SCOBY without a good yeast-bacteria balance. So you may want to look into getting a new one with some good starter tea. Here are tips on acquiring a good quality SCOBY.
Don’t ferment at room temp for too long. If you wait too long before refrigerating, your kombucha could get overly carbonated and make a mess when you open it. My F2 cycle takes about 3 days on average at room temp to get the perfect level of carbonation for me. Yours might take longer or take less. And it might change slightly depending on average room temp as the seasons change. But once you’ve got your timeline nailed down, stick to it and don’t wait too long before putting it in the fridge. Like I mentioned above, you don’t need to constantly burp your bottle because that releases too much carbonation. But you don’t need to swing too far in the opposite direction by fermenting too long without moving to the fridge.
If all else fails, you can force-carbonate. If you’ve tried all these methods and are unable to create carbonation naturally, you do have the option of force-carbonating through kegging. I’ve personally never done this myself, so I cannot speak from personal experience. But I do know that this is a possibility. If you have a keg, you’d essentially just flavor your kombucha right after first fermentation, then keg it and serve it on tap. I’ve heard mixed messages about whether or not a SodaStream works well for kombucha — a lot of people seem to say that it makes a huge mess. If I give either of these options a go in the future, I’ll be sure to update this post!
I’ve heard some stories about eggshells and raisins...
There’s a common tip I keep seeing online about adding a raisin or two to each of your bottles to help promote fizziness. The theory is that since raisins are sweet, it’ll help give the yeast more sugar to feed on without necessarily affecting the flavor of the brew. With that logic, I’d just recommend using more of whatever fruit flavor you were using in the first place or just adding a tsp. of sugar. I haven’t found this “raisin method” to be any more effective than using fresh fruit or adding extra sugar.
People also recommend adding crushed up/powdered eggshells to your bottles before sealing to help stimulate carbonation. I’ve never needed to resort to trying this method myself — especially when all my other tips have been successful. I also don’t really love the idea of having to save eggshells or cracking open an egg unnecessarily just to try this tip out. But that’s just me.
And hey, everyone’s kombucha-brewing variables are different, so if either of those tips work for you when nothing else has, I won’t knock it! Do what you’ve gotta do for your bucha.
What if I want carbonation but no flavoring?
You don’t necessarily have to add fruit flavoring to create carbonation. You can try bottling the kombucha right after first fermentation and sealing it airtight. Then let rest for a few days at room temp, then chill before opening to see if it built up carbonation. If it didn’t, or if it took too long, your yeast might’ve needed more sugar to eat. Try adding a teaspoon of sugar per 16 oz. bottle, then undergoing F2 again to increase carbonation.
*On this page, you’ll find some affiliate links to sources where I’ve purchased my ingredients/materials that I use. I may get a small cut of Amazon's profit for finding + recommending them to you. It won't cost you any more than you’d normally pay for them. I went through a lot of trial and error to find low-cost, high-quality options to save us all money. But feel free to purchase from wherever you like!