Fizz Factor: How to Increase Carbonation…For Advanced Brewers

This post is a follow up to Kombucha Bubbles: How to Increase Carbonation…for Beginners. If you are looking to increase your fizz factor while brewing Kombucha, try those techniques first and if you are still unable to achieve the carbonation you are looking for, only then try those listed below.

These methods are intended for the more experienced Kombucha brewer and even then only for those who have extra cultures to experiment with.  I recommend using one method at a time to see how it works and avoid over yeasting your brew.

First though, to understand what we want to accomplish, let’s take the opportunity to more deeply explore the yeast/bacteria symbiotic relationship!

The Yeast/Bacteria Relationship

The bacteria and yeast in the starter culture work in symbiosis to transform tea and sugar into fermented Kombucha tea.  The yeast consume the sugar and create ethanol (alcohol) and carbon dioxide (our fizz factor!), then the bacteria consume the ethanol and convert it into healthy amino acids.

The balance between the yeast and bacteria can be a delicate one.  If there is too much yeast in your brew, it can cause the bacteria to struggle; the other way around and your brew has little to no fizz.  As always in life, strive for the ideal balance for optimum results.

A brown and white Ying-Yang demonstrates balance.

Symptoms of an unbalanced Kombucha brew that may need a yeast boost:

  • Kombucha sours slowly or takes too long to reach the desired tartness

  • Little SCOBY growth

  • Lack of carbonation

What is Yeast?

Microscopic close-up of the s.cerevisie yeast body shows the tiny buds beginning to form. These will eventually become new yeast cells.

Notice the buds coming off of the S.cerevisiae yeast bodies, this is how they reproduce.

Yeasts are single celled organisms that have been used in baking and fermentation for thousands of years.  They belong to the kingdom Fungi (Kombucha is not a mushroom, people!).

Each Kombucha culture has its own variety of bacteria and yeast; though all of them will have acetobacter and saccharomyces, the exact composition may vary.  Some of the common strains of yeast in the culture include: Saccharomycodes ludwigii, Saccharomycodes apiculatus, Schizosaccharomyces pombe, Zygosaccharomyes & Saccharomyces cerevisiae.

DID YOU KNOW?  “Saccharomyces” is derived from Latinized Greek – saccharo- “sugar-” and myces “fungus”. Cerevisiae comes from Latin and means “of beer.” Cerveza anyone?

The yeast are the brown strands or strings that you find floating attached to the culture or collecting at the bottom of the jar.  They thrive at lukewarm to mildly warm temperatures which is the reason why the tea solution must cool prior to adding the culture.  Too hot and they die off.  Yeast release CO2 and ethanol.  It is the CO2 causes bread to rise and gives beer and Kombucha its natural fizz.  Roll up your sleeves and let’s go yeasting!

Warning: Remember, Kombucha bottles may explode if left unattended. Kombucha CO2 can build up quickly, especially with these techniques. Bottles must be monitored and burped, and it is recommended that one takes extra care when using these techniques as the increase in yeast activity can be significant. Store your secondary ferment bottles in a cooler, box or small enclosed cupboard to prevent additional damage. While I have never experienced an exploding bottle, I have heard the stories.

Brown strings of yeast collect at the bottom of the vessel and on the SCOBY. They help increase carbonation in your Kombucha brew.
Yeast strands are brown and collect at the bottom of your brewing vessel

Yeast Manipulation Techniques for Increasing Carbonation

Take Starter Liquid From the Bottom

Yeast is distributed throughout the Kombucha, whether you can see it or not. Once the yeast have done their job, they collect at the bottom of the brewing vessel. When they join together, they form the brown strings you see in the photo.

Normally, in order to preserve a healthy balance of bacteria & yeast, the starter liquid is pulled from the top.  This ensures that we don’t over yeast the brew (a lesson I learned the hard way).

However, if we are looking to boost our yeast quotient, the best place to find them is hanging out towards the bottom, which makes gathering them much easier.  Here’s what you do:

  • Pull 2 cups of yeastie starter liquid from the bottom of your brewing vessel.
  • When you have completed your brewing process (use 1 cup less water to accommodate the extra starter liquid), add the yeastie starter as the last step.
  • Cover and if possible place near a source of warmth (heating mat, warm stove, in a crock pot on low, etc) to keep the yeast active.
  • You should notice more carbonation within 1-2 brewing cycles.

Increase the Amount of Tea

The caffeine present in the tea will stimulate the yeast to remain active rather than allowing them to take their normal rest cycle.  Add an extra teaspoon or two (1-2 tea bags) of green or black tea to achieve the desired result.  Green tea has been noted for its ability to boost carbonation but my experience has shown me that the culture prefers a variety of teas to thrive – so don’t be afraid to mix it up.  Check out this blog post for more information on the best teas to use for fermenting Kombucha.

2-Stage Fermentation

This technique is described by Len Porzio of Balance Your Brew. I have never tried this method: mainly because I go with the flow – sometimes my brew is super bubbly and other times it is more flat and I’m cool with that. Len is a muy respected Kombuchero, so let’s see how his method works:

  1. Filter the fermented KT with a cheesecloth into a plastic bottle (a 2 Liter soda bottle works great for this) – you don’t want to prevent all of the yeast from getting through, this is just to remove the ooglies.
  2. Fill the 2-liter bottle all way to the rim with the KT.
  3. Gently squeeze the bottle to remove excess air before capping.
  4. Allow the bottles to remain at room temperature.
  5. Check the amount of carbon dioxide pressure building up by squeezing the bottle.  You want it to feel hard, like a basketball.  This process usually takes 1-2 days but may take longer if yeasts are lacking.
  6. Once your bottles are hard, transfer them to the fridge to deactivate the yeast (go dormant) and reduce the amount of pressure that has built up.
  7. After a couple of days in the fridge, gently pour the liquid into glass bottles.  You should notice fizzy bubbles as you pour, but do not pour so fast that it froths in the bottle.
  8. Take care not to allow the spent yeast that has collected on the bottom to enter the bottles.  Discard the spent yeast.

Len sez: Don’t Forget: Fill your bottles up to the rim & sample your brew when pouring from plastic to glass- if too tart, add some sugar or agave to mellow the flavor.

Crabtree Effect

The Crabtree Effect is not an overpriced soap store or a bad 70′s action picture. In fact, The Crabtree Effect is a normal part of the Kombucha brewing process. It occurs when an excess amount of glucose (sugar) is introduced too quickly to the yeast.

Much like a typical family after Thanksgiving dinner, the yeast fall into a “food coma” and stop reproducing.  Usually, this is great as it allows the bacteria to kick into gear and maintain balance. However, if we want the yeast to keep working, we need to prevent The Crabtree Effect from occurring.

To prevent your yeast from passing out on the job, gradually add the normal amount of sugar over the course of three days.  This allows the yeast the chance to keep up with the amount of glucose present in the nutrient solution.

Here’s what ya do (all measurements based on 1 cup of sugar per gallon of nutrient solution, scale to fit your needs):

  • Day 1, add 15% of the sugar = 2-1/2 tablespoons
  • Day 2, add 30% = 1/3 cup
  • Day 3, add the remaining 55% = 1/2 cup + 1 tablespoon

Now you’ve got loads of tips and tricks to try next time you are feeling like your brew is falling flat. 

Have you tried any of these techniques?  Did you get loads of carbonation?  Have other tips for boosting the bubbles?

Share your story in the comments below =)

Hannah Crum, the Kombucha Mamma!Hannah Crum is The Kombucha Mamma, founder of Kombucha Kamp, Industry Journalist & Master Brewer, educating others about Kombucha since 2004. Connect with her on Google +
Kombucha Mamma SCOBYs & Kits ship free in the US!
38 Responses to Fizz Factor: How to Increase Carbonation…For Advanced Brewers
  1. Jackie

    Thanks for listing these, I sometimes can’t get the carbonation the way I like it and I am going to give some of these a try… Love your site!!

    • Penny

      I have only been brewing for a month and just poured up my second batch. But both have been fizzy. I can’t explain why. I just add sugar and tea to scoby with kt and cover with cloth. Guess the mother I received was a really great one.

  2. Jennifer

    I just wanted to 2nd the thought that the bottles can and will explode. I’ve had two of my GT bottles explode and I was thankful both times that no one was near them. I do not keep them in a box orcontainer, but in a room all to their own. I’ve always feared that they might go off just as I’m putting them in the frig.

    Thanks for all the tips.

    • Thanks for sharing your experience, Jennifer =) I’m glad nobody got hurt. Safety first!

  3. victoria c.

    Hannah, love your two pieces on carbonation, thanks. I totally agree that a heightened sensitivity to carbonation levels is acquired by home brewing Kombucha. In the beginning, I did a lot of research on the topic to make sure my bottles were nicely carbonated but now that I’m also doing continuous brewing, I find I enjoy the more subtle ferment also.

    Recently I’ve started adding pineapple to my second stage ferment and the carbonation levels are super high. Oh my god, it froths forth like mad. During the second ferment stage; I find that ginger & lemon alone add quite a bit of carbonation so I usually make these two ingredients my base and then add herbs like sage, rosemary, thyme. The most carbonation so far has come from adding pineapple.

    I believe the high level of enzymes in ginger, pineapple and papaya encourage added carbonation. They have proteolytic enzymes that break down proteins; pineapple has bormelain enzyme, ginger has zingibain enzyme, papaya has papain enzymes. Bacteria and yeast are protein/ amino acid-based. Proteolytic enzymes digest bacteria and yeast. Carbonation results from this break down.

    This enzyme theory makes a lot of sense especially given that ginger beer and fermented pineapple are ancient effervescent elixirs. A biochemist on our team could add further insights.

    • Faith

      Hi Victoria,

      Do you add whole pineapple slices, or fresh pineapple juice.

      In general with fruit is it better to add, pieces, puree, or juice?

      Thanks so much!

      • The smaller the size of the flavoring agent, the easier it is for the Kombucha to absorb the flavor. By that logic, juice or puree would yield the most pineapple flavor. Let us know which you use and how it turns out!

  4. I am still playing with my brews to get more carbonation and notice that when I add ginger to a brew it really increases!!

  5. Sara

    Thanks for all these tips, but I’m in search of what to do when you have too much carbonation and yeast production? I’ve been brewing for several weeks now and can not seem to produce a baby scoby. I’ve reduced the steeping time of my tea, I’m taking the starter from the top, but still with no luck. Any thoughts? Thanks!

    • Sounds like you need to rebalance your brew and grow a “master race” – Len Porzio’s site – The Balancing Act – has instructions on how to do that.

      • Sara

        Hi Hannah-

        Yes, I’ve been in contact with Len, but with no luck. I wasn’t sure if anyone had any other ideas. Thanks for the suggestion- Len is amazing!

        • Send me an email at customerservice [at] kombuchakamp [dot] com and we can try to figure it out together.

  6. sharon rosenberg

    I just did my second c/b–poured my gal of second brew into the top where my scobys had happily spread themselves across the entire opening—well by pouring I disturbed the mother and now on day 3 of second brew she is still all folded up hasn’t spread across to reseal—will this effect my carbonation—and how do I pour into with out disturbing the scoby?

    • No worries! The new layer will grow across the top and create a new seal.

  7. Darlene

    I have a very thin baby in brew of 7 days. Could I pour some liquid from my hotel over brew and let stand for a few days more? Would this make a healthier scobie? Also take up more sweetness?

    • This time of year, it is difficult for the Kombucha culture to reproduce and to make properly flavored due to the colder temps. Adding more starter may not increase your SCOBY’s size but it would help consume the sugar in your brew. We recommend using a heat source to keep your cultures viable through these colder months.

  8. Vic

    I’ve been putting in 1 rather large slice of fresh ginger to my bottles. Maybe that’s why I’m not getting much fizz. Those of you who put small pieces, do you strain your kombucha before drinking or do you just drink those small pieces of ginger?

    • You can strain out the flavorings or not. Adding a small amount of sugar as primer for the yeast will help increase the carbonation. In a 16oz bottle, 1/4-1/2 tsp of sugar will work.

  9. Hi, this website is very helpful! I was just wondering if there are any compatible yeasts such as brewing yeast for beer that can be introduced to your KT to help promote carbonation at bottling. thank you very much!


  10. Linda

    I have used ginger but in what form do I use lemon. Thank-you for all this wonderful, useful information

    • You can use fresh lemon juice or lemon zest. Some folks use essential oils. Experiment and see what you like best.

      • Stephanie

        I dehydrated fruits and pulvarized them. I will be trying lemon as one of those powdered fruits.

  11. April

    I reserve 2 cups of liquid for my next batch and have consistently found my brew to have great carbonation. But is this too much liquid? The reason I ask is because I use green tea and my scoby’s are not very large nor thick. When I used half green tea and half black tea, the scoby’s were thick and white… just beautiful! BUT the black tea caused an old medical issue (intersitial cystitis) to flare its ugly head so I went back to green tea only. Would you have a recommendation for another tea to add in with the green tea to still get a healthy scoby? Yerba mate and the white peony tea seem a little pricey (for our budget) for the 4 gallons we make weekly. Thank you!

    • 1-2 cups per gallon batch is an appropriate amount of starter liquid. Everyone finds their ideal recipe based on their personal preferences and needs. Yerba mate would be the best substitute for the black tea as it is high in nitrogen. Hibiscus can also be used in the primary fermentation and yields beautiful pink SCOBYs. Switching up the nutrient solution for your cultures from time to time will also perk them up. Or brew a batch of black tea for your SCOBY Hotel to keep them happy. You can use the liquid as starter to bolster the fermentation while minimizing your exposure to the black tea. As always, trust YOUR gut!

  12. Robi

    Vic – I grate my ginger, sometimes large or small grate where it’s almost ginger juice I’m adding! I am careful though and only leave 3 days then strain off and rebottle leaving for a period of weeks, burping everyday. I jumped into continuous brewing right off, never have carbonation issues since I bottle twice, once for flavouring and once for melding and mellowing of flavours. I just love this whole process. Thank you so much Hannah for your time and energy in sharing your KT expertise. I’ve found your website has been so helpful these past months since my first tasting of homemade kombucha. I now have over 9 gallons in 4 separate vessels of continuous brewing on the go. Not all for me though. LOVE IT! Robi

  13. Ritesh Shah

    hi, thx for info, i guess due to occurrence of carbtree effect my kombucha got bad, cuz i was introducing lots of suger while making it & was not aware that yeast may stop working…

    again my neighbor had nice result when she use this proportion 8 cup water (approx 1 ltr) less then 1 cup sugar, & hardly 1 spoon of tea.

    this way her KT gets bubbly naturally..

    thx again for sharing & making this page.. :)

  14. Lori Wulf

    I am so glad I found your site. Thank you Hanna for all the helpful I formation. I am currently experiencing carbonation issues. I can’t wait to try some of the tips I learned here today.

  15. Marietta

    I realize that I have not been filling my bottles to the top. Thus no carbonation. However, there is carbonation when I draw a glass of tea from the brewer to drink. I have used pureed strawberries and pureed peaches to flavor the KT for the second fermentation. Again, no carbonation. In the future, I will add some sugar to the pureed fruits and fill the bottles to the top to be sure that I get carbonation. Also, the pureed fruits are great added to a glass of KT from the brewer.

    Thank you for the excellent information and support on how to get started and how to keep on doing (brewing)!

    • kkadmin

      Give your CB a quick stir to get the yeast from the bottom into the liquid. Then when you decant into your bottles, you will have yeast strands present which will help you increase your fizz. Let us know how that works for you!

  16. Grace

    So how long can I do the 2nd ferment at room temp before putting in refrigerator? Also do you use fresh or dried herbs?

    • kkadmin

      Nearly everything with Kombucha is to taste. For instance, we never put our KT in the fridge as we prefer to let it bottle age. It will continue to ferment in the bottle and the flavor will shift over time. If you have flavorings in your bottles, you will want to move them to the fridge to prevent off flavors or you might strain out the flavoring if you intend to let the bottles age for longer periods of time. As for dried or fresh – they both work great! I like using the fresh herbs from my garden, but also used dried flowers and barks as well. Happy Brewing!

  17. Virginia

    I may have gotten the ratios of starter KT to new batch wrong in my CB. I’ve been using the CB for a couple months, and have never gotten the end result that I had using a regular gallon jar. The first batch in my CB I left for a few days before tasting it and it was quite vinegary. So each time I make more, I start tasting it the next day, and it’s always more vinegary than I like it. The last few batches have been pale in color and with very little carbonation, even adding fruit juice to the 1st bottling (I use the heavy glass jars with the locking flip-top lids). The end result is more sour than I’d like and with very little carbonation. I always use the same tea, Darjeeling and oolong mix.
    Gratefully, I had started a hotel, so just today made a brand new batch in my gallon jar, using a new Scoby and some KT from a few batches ago when it was darker and more fizzy.
    Any ideas what might be going on?
    I’m loving making my KT, I drink at least 16 oz a day, and really would like to get the hang of the CB.

    • If your CB is souring too quickly, that is usually a sign that it is time to clean it out as the yeast has built up on the bottom.

      Stirring the CB just prior to decanting will help with both of these problems. When we brew in a jar, in order to remove the Kombucha, it is upended causing the yeast on the bottom to get into the bottles. Then, when the fruit or sugar is added, that yeast reactivates to create the carbonation.

      You may need to reset your CB now and then in the future, stir before decanting to get the carbonation you are looking for and to keep the CB balanced.

  18. Rebecca Anderson

    Thank you so much for the time and effort you put into this site. I received my Scoby from a lovely friend and my first batch was wonderful. After that, however, it took forever to ferment with a thin scoby. After reading MUCH (have I come to the end of the internet yet? lol)I discovered that we keep our house too cold (down to 65 at night). I added a heat source by sitting my jars on a chair over a heat vent and covering the whole thing with a sheet. They are now fermenting happily. My favorite flavoring is Ginger, grapefruit and a touch of honey. Oh my goodness! Thank you again. I love this site. It is the best!

  19. Leanne Burlew

    I love your site. My CB brews very quickly as I live in SW Florida and I will start stirring before decanting to help slow it down. I add an ounce of 100% juice to my 16 oz bottles then add hibiscus and other flavorings. 2 days on the counter the into the fridge. If I want super bubbles after the second fermenting I rebottle with some hydrated chia seeds in about an hour it is like soda.

  20. Penny

    Do I keep putting the scabies I purchased from Kombucha Kamp in my brewing vessel every week, or am I suppose to dispose of them? I am on the 4th week of brewing. Each week a new scoby layer grows on top of the vessel. The original scoby lays in the vessel and looks the same.

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Continuous Brew mini-FAQ

How does it work?

By changing the starting ratio from…
1 Part KT:9 Parts Starter (orignial method)
3 Parts KT:1 PART Starter Liquid (CB method)
…the brewing cycle is dramatically reduced (just 1-2 days to complete).

Posted in: Continuous Brew mini-FAQ

What about the Sugar?

Your colony of bacteria and yeast will be hungry and will very quickly process the small amount of sugar into mature KT.

Posted in: Continuous Brew mini-FAQ

I don’t want to take on more work.

Actually, CB results in less work.  One example: a more streamlined bottling experience, without the need to lift your brewing vessel, clean it every week or deal with the mess afterwards.

Posted in: Continuous Brew mini-FAQ

I can customize the flavor?

Sure, just drain mature KT and add starter liquid to taste.  Or for bottles, flavor as desired – no funnel, no mess!

Posted in: Continuous Brew mini-FAQ

It’s actually healthier?

So says Michael Roussin and experts worldwide.

Posted in: Continuous Brew mini-FAQ

Will I have too much Kombucha?

Not at all.  Having it on tap will change your perspective.  Plus, you’ll find friends, family and neighbors eyeing your Kombucha set-up with envy and maybe even helping themselves to a fresh glass.

Posted in: Continuous Brew mini-FAQ

Really? You’re telling me it’s fun?

Yes.  With a straight face.  It is.

Posted in: Continuous Brew mini-FAQ

I’m nervous. Is it hard?

Don’t be nervous.  You have the experience of hundreds of homebrewers backing you up in the form of my detailed instructions and maintenance plan.  You will be guided along the way.  You will save time and effort.

Posted in: Continuous Brew mini-FAQ