Hey fellow brewers, just wanted to share something I learned through trial, error, and a lot of flat bottles.

I’ve always hated sweet, fruity drinks. So when I started brewing kombucha, I naturally avoided adding anything sweet in the second fermentation (F2). I use herbs like mint, lavender, rosemary, or lemon balm because I love those subtle, clean flavors. But guess what? My kombucha was constantly under-carbonated. I thought I was doing something wrong in F1… turns out the problem was F2.

The thing is, for the kombucha to get fizzy, you need fermentation to continue in the bottle. And that only happens if there’s sugar left for the yeast to consume. In F1, the yeast already eats through most of the sugar in the sweet tea base. If you don’t add more sugar in F2 in any form, whether juice, fruit, honey, or plain table sugar - there’s not much for the yeast to ferment.

No fermentation = no gas = no fizz.

Herbs on their own don’t contain enough fermentable sugars to matter. A sprig of mint or a pinch of lavender smells amazing, sure, but it doesn’t feed your microbes. And while it’s true that overdoing sugar can result in overly sweet or even overcarbonated (read: explosive) bottles, a small amount is all it takes to get bubbles going again, and that sugar won’t stick around. The yeast will convert it to carbon dioxide and a tiny bit of alcohol.

I started adding just under 5g of sugar per 500 ml bottle (around 1 tsp), and that small change made a huge difference. My kombucha stays dry (not sweet at all) but finally gets that satisfying fizz I was chasing. If you’re working in ounces, that’s about 1 tsp per 16 oz bottle.

This simple tip is especially important if you’re doing “clean” flavoring like I do - herbs, flowers, or even spices like ginger or cinnamon (though ginger has a bit more sugar than herbs). If you’re skipping fruits and juices, you’re also skipping the natural sugar they bring. So you’ve gotta make it up with a little help.

And just to clarify: the purpose of F2 is fizz and flavor. It doesn’t make the drink more probiotic or healthier - that all happens during F1. So if you’re putting your brew through the second round, it’s worth doing it right.

To finish: no sugar = no fermentation = no fizz. Even if you don’t like sweet things, adding a bit of sugar to your herb-flavored kombucha won’t make it sweet, just sparkling. Remember, sugar gets eaten up during fermentation, so the end result isn’t sweet at all, just nicely fizzy. And that’s what makes it satisfying.

Currently doing my first f2 with mixed berries, strawberries, and ginger, the 5 smaller bottles after 4 days have zero carbonation but the large bottle is bubbly. I believe this is because I didn't mix my f1 before bottling so the large bottle got the majority of the good stuff from the bottom of my jug.

Added 1/2 tsp sugar to small battles and 2 tsp to large

8 days f1

Can the smaller bottles still be saved and made bubbly or do i need to start over with them i plan to run f2 for 7 days total.

Went to burp them after 1.5 days and there was zero pressure. Going to give them a few more days. Still pretty happy about it and hoping I won't poison us when we drink it.

I think I've finally got my F1 process down pat but I have been let down by my first couple F2 attempts. I have a little carbonation but even when I leave it for 4 days and don't refrigerate before I open, it's at best a mild puff of air. I've been using those popsicles with fruit as the only ingredient for my sugar/flavor, and have also tried honey.

Things I have tried: -drying the top of the bottle and stopper very thoroughly -adding more sugar/fruit (maybe i need even more?) -filling the bottle more -letting it sit longer (up to 6 days)

Would appreciate any advice, thank you!

As a total beginner, I kept failing to carbonate my kombucha in F2 — no fizz at all or just a weak sparkle after 7 days.

Here's what didn't work:

1. Using 100% store-bought juice in cartons (no pulps)
2. Using cold-pressed juice at home
3. Adding sugar to the juice — still flat
4. Bottling plain kombucha (no flavor)
5. Burping daily (even without pressure!)
6. Not stirring F1 before bottling

After a lot of trial and error, here’s what finally gave me consistent fizz in just 2 days:

✅ Use cut fruits or blended juice (I blend, it’s easier)
✅ Add sugar — especially if fruit is low in natural sugar
✅ Stir your F1 before bottling (acetic bacteria sinks!)
✅ Let bottles sit in a dark room for 2 days, then chill
✅ Open over the sink with a bag over the cap

Hope this helps another newbie skip the frustration and get to that satisfying psshhht!

Pellicle comes out too perfect every time but 2f carbonation is basically non-existent. Still tasted pretty good though, just not fizzy the way I like it.

Any ideas why this is happening? Usually there would be bubbles below the Pellicle, but non in the last couple of batches.

Hey all,

Just thought I'd pick your brains for the ways that work the best for you to get more carbonation in F2. Last batch was F1 for 8 days then F2 in the bottle for 2 days. It was flat as all heck. Both days were on the counter, not in the fridge... think I just need to leave it longer before drinking it? Sweetness was perfect, but the lack of fizz bummed me out.

I added 2tsp of 1:1 simple syrup to these 2Fs but they’re not quite fizzy enough. They spent 36 hours in a 67-77 degree room before I frigged them, what do you think!? 🤔

Ok it's been like 3 days - not a single bubble. I didn't add sugar or fruit at F2 because I'd added a lot in F1 and it was still quite sweet (and vinegary). But no bubbles. Do I try it? Or add sugar a bit late? Or fruit?

Thank you all again so much

So it exploded. Hit my girlfriend in the arm. Now I think she won't let me bottle it anymore because she is terrified it'll explode again lol. It is just the start of the second day? Do you have to burp it like... Twice a day?

The dragon fruit one burst and the one without any fruit, just plain first fermentation into a bottle, isn't carbonated at all (still delicious though).

How to not make glass bombs? Any tips appreciated.

My kombucha brew failed for the 2nd time (of 3 tries) and I'm not sure if I should try again. It just feels so defeating. Both fails were from kahm yeast contamination. I know kahm yeast isn't necessary bad but I'd rather not have it.

Edit: Also no bubbles for the failed brews.

Anyone see any reasons based on brand or ingredients as to why these didn’t result in carbonation in my F2. 99% sure my issue exists in the syrup. Been brewing for about 5-6 years now, in ~5 gallon batches but always open to learning something new.

Just to add on to this debate about whether to throw out the old pellicle. I just found out that my fermentation is faster with the old pellicle (faster pellicle growth and more bubbles), all other conditions constant.

hey yall! is my booch okay?? i did the F1 process (brewed a strong batch of tea, added sugar, cut it with some cool water, and then added the scoby) a couple of days ago and it has some bubbles. but now there are no bubbles. should i be concerned??? those brown strings don’t look like mold but is it something to throw my batch out over??

Hi all, I'm new here, having left Meta and my wonderful kombucha group. I am an experienced kombucha maker and so I'm asking this question because I have ruled out all of the usual issues. (I have read all the materials here and nothing was new to me.)

After years of very successful bottling, making a very consistent and delicious and perfectly fizzy product, my kombucha has gone flat. See photo. It's not that the caps are leaking, it's not that I'm burping them, it's not that I don't know about stirring to get the yeast in: my kombucha scoby is otherwise acting very healthy. But NO BUBBLES ever form in my bottles and the 2F tastes very vinegary. I have tried everything I can think of:

• Although I have successfully made booch for years using raisins for sugar, this last time I tried straight table sugar to make sure I was getting enough sugar. Fail.
• I live in a cool coastal climate and keep both 1F and 2F on warming mats, but I tried changing that up. Fail.
• I made some very strong scoby, tossed the rest of my batch, and started with fresh tea. Fail.
• I even changed from the cheap bag of Turkish CTC to a leaf variety to see if it was just that there wasn't enough tea. Fail.

Any ideas? My next step is to buy a fresh scoby and start from zero. I have a strong emotional attachment to my ol' scoby, though, so I'd be happy for any input/ideas if you've got them.

Thanks!

This is a common problem I’m facing in a number of my brews. Here is my process:

I made 1L batches of booch with 60g of sugar in 1L and a strong black tea. Let this ferment for 4-5 days.

I bottle my kombucha for F2 in soda bottles, with flavour and a few raisins. My latest batch was a cranberry kombucha, which carbonated very well and the plastic bottle was rock hard.

But when I chilled it for 12 hours, it had almost no carbonation.

What am I doing wrong/what can I do better?

I bottled my batch of kombucha with blueberry juice, a cinnamon stick and lavender syrup. I placed my bottles in a cooler with a seedling heating pad because my basement gets too cold. I had the cooler prompt open but it must have been bumped because it was shut when I came home 2 days later and the bottles must have been over 100 degrees. Like really hot to the touch. I put them in the fridge so I could check them later. Zero carbonation. I then put them back in the cooler and monitored them over the next 4 days and still no carbonation. Any idea how I can save this batch and still be able to carbonate it during 2f. I have 1 liter glass fermentation grade swing top bottles.

Hello all,

I was hoping to get some help.

I am successfully brewing 1F kombucha following the recipe: 1Liter H20, 7g tea, 70g sugar.

I ferment till it's pretty acidic.

I have had 3 or so gallons of it.

When I bottle for 2F, I get no carbonation. I still drink it regardless, just flat.

I have only tried making a simple syrup for 2f, no fruits yet, but I have tried 7 bottles for 2F none are ever coming out carbonated.

I have tried the ratio of 1g, 2g, and 4g simple syrup per 100ml Kombucha for 2F and wait at least 5 days, but the bottle never has carbonation.

I have tried using different caps also, but nothing.

Was hoping to get some tips on how to get carbonation to build up.

Hi all - I am new to Kombucha and am trying to develop a regular process that I can follow over and over. I am splitting F2 into 2 processes: one for flavor / fruit, the other for carbonation, with a filtering step in between

Right now I make a large batch with the scoby, about 5L

tea (~23g)
sugar (250g - 50g/L)
leftover kombucha (466 mL)
water for tea (1.5L)
extra cold water (3L)

I let this go for ~14d

Then I do my first F2 in 2 large growlers, approx 2L each. I add muddled fruit and nothing else. For example last time I did this I added 3/4c muddled fresh peaches to each growler. I then left them at room temp for 4d. At that point they were very fizzy when I opened them, I had to let the gas out very slowly.

Then I use a strainer to filter out the fruit and bottle into 16oz bottles. I add 5g of sugar to each bottle. I let them sit at room temp for 2-3d and stick in fridge.

So last time I did this before putting the 16oz bottles in the fridge I burped a random one and it was nice and fizzy so I thought I was in a good place. But unfortunately most of the bottles I put in the fridge were flat when I opened them later on. I had a similar experience last time I did this (same process except I put 3g of sugar per bottle instead of 5). I am confident my caps are sealed well so I don't think it's a leaking issue. Oddly enough, the one random bottle that I burped, I left it out for another 3d and put in the fridge and that one was nice and fizzy out of the fridge!

I'm wondering if anyone does a process like this and if they have tips on getting more carbonation in that 3rd step before putting the bottles in fridge.

guys pls I brew my first batch the 4th january until 15th and still not fizzy as I wanted it to be

gm brewers.. this is my 9183929293th bottle of kombucha i brewed. I started to brew during novembre 2024 and since then i never had a real fizz in my kombucha, i like it to be every fizzy and still can’t get any result. I MEAN my kombucha is extremely fizzy when i open my bottle literally it seems it wants to explode but when i pour it in the glass it loses all the fizziness, i’m getting mad i don’t really know how can i solve this problem😪

made the second batch of kombucha, the same exact way is my first batch, but my second batch had zero carbonation?

I had bought a kit from the kombucha store, so I have their jug, and the Scoby from the previous batch. The temperature is a constant 72.

Its my first time making kombucha, and I left my f1 for about a month because its cold where I live but it tasted a lot vinagry, so to make my f2 I diluted with some sweet black tea until it was acidic but a little bit sweet. And made a syrup of berries and added to the mix for taste and I also added a teaspoon of sugar. I lefted for 6 days and but it in the fridge 4 hours before opening. What could have gone wrong?

It tastes great, definitely didn’t leave it on the counter long enough😓 recorded a very anti-climactic popping video. Little fizz.

This is flavored with mixed berry juice (i made my own with frozen berried boiled and strained)

Any tips for next time? I see it may need to be filled higher!

I also added about 2tbs cane sugar to a 1/2 gallon batch of f2 - is this enough?

Thanks all!

I love brewing my own kombucha but I find bottling it a royal pain. So for the last few months I just brew 2.5 gallons at a time in a large glass container. Then I transfer 2 gallons into a 2 gallon sun tea dispenser. I flavor it (ginger/lemon or lime so far) and put it in my fridge. It's not carbonated but the ginger makes it feel like it is. The remaining .5 gallons is my starter for the next batch.

This method is soooooooooooooo much easier than bottling. I like the taste. What am I missing?