Kombucha FAQ

FAQ Frequently Asked Questions about Kombucha Mushroom Tea.


Top 10 questions about Kombucha Mushroom Tea


  1. 1.              What is Kombucha Mushroom Tea?
    1. a.     A miraculous semi-sweet, slightly carbonated, pleasantly tasting health enhancing functional probiotic tea, believed to date back to Ancient China. 


  1. 2.              Can I make Kombucha Tea at home? Is it Safe?
    1. a.     Yes. The U.S. FDA , and CDC (Center for Disease Control) and numerous U.S. peer reviewed research has found kombucha to be safe when made at home.
    2. b.     Follow our simple recipe (Tea, Sugar, Kombucha SCOBY), 7-14 days , have great kombucha tea. Continue to add water, sugar and tea for a lifetime supply.


  1. 3.              OMG, what is that!
    1. a.     This fermentation process produces a gelatinous mass which floats on top of the ferment and  what has been referred to as a  “Tea Fungus,” “Mother,” or “SCOBY” and alternatively by friends and neighbors as  OMG, what is that!. This mass may be ugly or beautify. The appearance will often reveal what is happening inside your ferment, and you can tell a lot how healthy and safe your kombucha is.
    2. b.     SCOBY a acromion

Others have described these balance between the bacteria and yeast as mutually beneficial  and supporting. It is not.  Yeast and bacteria are antonigist .  Each trying desperately to control the environment for themselves. Kombucha is the result of the delicate balance them and other resources and nemesis.

  1. 1.      


  1. c.      Kombucha is fermented tea and sugar

                                               i.     Principle product of kombucha is Acetic Acid,  Gluconic Acid and Fructose.  (see everything that’s in Kombucha)

                                              ii.     Primarily an acetic acid bacteria ferment as opposed to the common yeast ferment . This is an important distinction. Common  ferments such as beer, wine, apple cider and vinegar, and Lactobacillus (bacteria) or Lacto-Soda ferments such as Water Crystals,  as Jun and Ginger Beer may employ the same yeast and bacteria as one utilizes in their kombucha ferment. The difference is the timing of the ferment. Kombucha is a simultaneous presence of bacteria and yeasts – yet have individual cycles, as well as the predominance of bacteria.

  1. 1.     Gluconobacteria, and Acetobacter xylinum two of the four, subspecies of the Acetobacter species of bacteria, that produces Acetic and Gluconic Acid. Lactobacillus, another bacteria often, though not always found in Kombucha, produces beneficial Lactic Acid but does not produce gluconic acid .
  2. 2.     Species of acid-tolerant yeasts that have been found to help create kombucha include;  Brettanomyces bruxellenis /Dekkera, Saccharomyces, Shizosaccharomyces pombe,  Torulospora delbrueckii, and Zygosaccharomyces bailii  with guest appearances by ; Candida stellate, Rhodotorula mucilaginosa, Kloeckera, and  Pichia .  With Saccharomyces Boulardii, a well known and effective probiotic being made popular by GT Synergy’s Kombucha Tea. 
  3. a.     Note: that recent studies have discovered both a yeast and a bacteria sub-species that are unique to kombucha and are presently under the process of being so named as *kombuchae.

                                                                                                     i.     Gluconacetobacter Kombuchae  a bacteria that is unique to kombucha.

                                                                                                    ii.     Zygosaccharomyces Kombuchaensis a yeast strain that is unique to kombucha


  1. 4.              Does Kombucha contain alcohol?
    1. a.     All ferments produce alcohol.  The difference with kombucha, as opposed to all other ferments, including bacteria lactobacillus ferments, is that the Acetobacter species of bacteria, convert alcohol into acetic acid. As an example wine turning into vinegar.  The typical kombucha ferment is roughly ½ of 1% alcohol. About the same as fresh apple or orange juice after a day.
    2. b.     What is the difference between Vinegar and Kombucha?

                                               i.     The process is different. Vinegar is first fermented completely via yeasts followed by removal of the yeast then adding and completing a bacteria ferment.  The difference is kombucha has Acetic acid and Gluconic acid, fructose, active yeast and bacteria. Vinegar has acetic acid and bacteria.


  1. 5.              How much sugar is in Kombucha and do I have to use sugar?
    1. a.     Basic recipe starts off with 1/3 cup per quart of water. Just under 3 ounces per quart. Sweet like Southern Sweet Tea., or most Soda Pop. A typical range  ~ ¼ cup per quart or more say ½ cup per quart. Research studies use from  5% to 10%.  One can produce a nice ferment with only 3% or a stronger ferment close to 20%. Under is pretty bland while over 20% tend to stall the ferment altogether. The starting amount of sugar may be from 3% to 20% sugar depending upon preferences.  Remaining sugar - that sugar not used up during the fermentation is Time dependent. The longer you ferment the more sour /vinegary the kombucha becomes, and the less sugar remains.  Typical brewed Kombucha Tea has about one ounce of fructose per quart.. Oxygen levels, pH tolerance, Time and Temperature all play a role in the finished brew. 
    2. b.     Yes, there are many fermentable sugars, syrups and juices that may be used. Each would impart a difference both in taste and in benefits. For example Substituting Sour Cherry Juice for sugar produced significantly higher levels of the beneficial Gluconic Acid.
    3. c.      Using a Hydrometer or Brix meter can measure your beginning sugar levels and your ending sugar levels. From these values you can calculate the potential alcohol levels. You can also measure your Total Acids. By knowing your Total Acids and Sugar levels you can calculate a ball park remaining alcohol level.


  1. 6.              What kind of Tea do I use, and are there other teas, herbs and spices that I use?
    1. a.     Tea (Camellia sinensis) Black Tea, tea that has been “fermented” is the traditional tea used to brew Kombucha.  Black Tea has sterols, purine, tannins caffeine, and most importantly nitrogen.  All help form the building blocks of kombucha. Green tea, white tea, oolong tea, etc. are all camellia sinensis, which have undergone different processes. These different teas will form slightly different “strains” or character profile.
    2. b.     Herbs and spices may be added to the ferment and contribute their uniqueness both as to their taste and flavor as well as their medicinal quality. All of these will add or subtract from the “pure” kombucha ferment. In our opinion, herb, spices and additives should be added to a Second Stage ferment or to individual bottles where you can maintain the interiority of the “pure kombucha”.


  1. 7.              How do I make Kombucha Tea?
    1. a.     Kombucha is a simple home  process. Boil water, Add sugar, Add Tea, Cool, Add some previous brewed kombucha tea, Add the Kombucha “mother” , cover and let sit for 7-14 days.

                                               i.     Time and Temperature play a role. Kombucha doing better in the summer and slower, more erratic during winter.

                                              ii.     What  kind of containers can I use?

  1. 1.     Glass
  2. 2.     Ceramic
  3. 3.     Plastic
  4. 4.     Wood
  5. 5.     Stainless Steel


  1. 8.              How do I know when my Kombucha is ready?
    1. a.     You know your kombucha is good, just as one knows their other food preparations are good. -- Looks good, smells good, taste good..

                                               i.     Kombucha starts off as Southern Sweet Tea. Very sweet. With a pH around 5

                                              ii.     Left to ferment Kombucha goes towards vinegar. The longer the ferment continues the more sour  it becomes. (vinegar with a pH ~ 2)

                                            iii.     Kombucha tea is ready when it is semi-sweet, semi-sour according to your personal taste. (pH 2.5 to 3.5)


  1. 9.              Can I make Kombucha safer by using an airlock ?

                                               i.     Is Kombucha an aerobic (with oxygen) or anaerobic (without oxygen) process?


Question  in its entirety posed by Ted from the University of Florida.

Problem:  Contamination during the fermenting process of Kombucha is an ongoing challenge for the industry.


Since both Kombucha and beer “yeast” initially make CO2 and the CO2 is expelled in beer making out of the “airlock” shown below, I am wondering why in the making of Kombucha an airlock is not used and instead a tight weave towel is used. This can let contaminants into the fermenting Kombucha.  The airlock is helpful because it lets out the CO2 and does not let in contaminants.


My question is, "Does Kombucha bacteria REALLY need air to be healthy? "


Instead of a cotton cover why not use an airtight lid with and airlock connected to it like they use in beer and wine making to let out the CO2 and not let in any harmful contaminants that are found in outside air. (see picture below).


I do not believe the Kombucha bacteria or yeast of the SCOBY need "air flow" at all.  I think they will be fine without the airflow and a smarter approach would be an airlock.  I can find no research that says that the Kombucha bacteria, Leuconostoc mesenteroides nor Lactobacillus plantarum or even Luteimonas cucumeris and Lactobacillus brevis need "outside air" to thrive.  I feel they will thrive quite well in the CO2 riddled air of the crock with an air lock in place.  Just as in beer and wine making. Granted, I have no research to back up my theory and realize that bacteria is not present in beer and wine making, only yeast is present.


I guess it all comes down to this - Does bacterial such as the ones I just described need O2 to survive or will they do just fine in a closed environment of a Kombucha fermenting vessel such as the one pictured below. (Airlock Ferment)


Answer:          Hi Ted. good question. Hopefully I can shed some light. This often does come up. 

Folks find SCOBIES (Mushrooms) growing in bottles of Raw Kombucha Tea *  and ask the same question. They will also start a batch and only partial fill the container, leaving an air space, and tighten a cap. Others have advocated for the “Airlock” method citing success brewing this way. 


What first needs to be defined is what is “ kombucha Tea”. I define Kombucha Tea as fermented sugar and tea by specific subsets of bacteria and yeasts that produce Acetic Acid, Glucuronic Acid and Fructose.  As far as I know only a small handful of Acetobacter bacteria in this setting are capable of producing Acetic Acid and Glucuronic Acid, and the gelatinous mass (pellicle / SCOBY / Mushroom).  


In numerous peer-reviewed studies on Kombucha, lactic acid has not been found in their studies. Importantly these studies focus on Kombucha being a Acetic Acid Bacteria (AAB) ferment as opposed to a Lactic Acid Ferment (LAB).


As an AAB ferment, oxygen and air flow (exchange) is critical to production. AAB convert alcohol produced by the yeast to acetic acid only in the presence of oxygen. Only a minimum amount of oxygen is needed. However the production is directly affected. The more the oxygen and the greater the circulation the greater conversion completion. Additionally the production of the mushroom is directly affected. True a mushroom may appear in a closed bottle, but generally that mushroom is more flimsy and weak.


On your concern with contamination. Airlocks do help prevent contamination - yet contamination happens. Beer and Wine and Cider I believe have to be more “pure” in taste and character, they ferment longer and therefore maybe more susceptible to outside influences which taint the brew. Kombucha is really simply and quick. Kombucha home ferments small and cheap. Easy to toss out and start over or used for other purposes.** . Numerous studies have found Kombucha is safe and even when contaminated by mold or pathogens the liquid tea, with its low pH, would still be safe where someone to drink it. (though that is not ever recommended) 

The bacteria that you quoted below Leuconostoc mesenteroides, Lactobacillus plantarum, Luteimonas cucumeris and Lactobacillus brevis  are LAB. Luteimonas cucumeris is an exception as being aerobic, the rest capable of fermenting and producing lactic acid and acetic acid without oxygen and  Lactobacillus brevis can produce acetic acid, lactic acid, alcohol and carbonation with a very pleasing and healthy drink with or without the presence of oxygen or for that matter without yeasts. Around the world there are numerous local folk LAB drinks. It may well be that many simply refer to those local LAB ferments “Kombucha”. 


Simply zymurgy.

Therefore if one asserts Kombucha is a LAB ferment that yes to your query.

If on the other hand Kombucha is a AAB ferment then no, oxygen and fresh oxygen with air circulation, is required. 


note: that LAB are also capable of producing a mushroom (SCOBY) and have the advantage of fermenting at much colder temperatures. They do produce a very tasty drink that is extremely similar to Kombucha. 



  1. 10.          Continuous Brewing .  I have been a proponent of the Continues Brewing Method,  since I read Michael Rousins very scientific report on Kombucha. ( where Mr Roussin found that  many of the beneficial benefits of Kombucha Tea were not even produced until 20 days in the ferment which under the typical single stage ferment would be too sour to drink – but when fermented as in the Continuous Method all those benefits would be available in a pleasant and tasty brew.


Why my Kombucha is Sour. ( in their blog states that CBM causes sour kombucha , and I will address that 


There are many opinions on Kombucha posted on the internet. One rather long post anti-CB  form a respected Kombucha Brewer ( link) and to which I replied is listed below


Succession and Why We NEVER Continuous Brew, ( link)

This entry was posted on February 29, 2016 by Jessica Childs.

A Common Problem :

My Kombucha tastes like vinegar.


My kombucha ferments so fast I can't control it.



Hi Jessica.  sorry you have experienced problems with your brew. I have ideas on why that may have happened.


If that happened in your Continuous Brewing Method. I’d like to offer my suggestions on how you can improve  that as well.


The content is partial correct regarding Succession.  Only partial because all life cycles have an ebb and flow -


In the “typical” kombucha ferment that is generally around 9-14 days. (Dependent upon Temperature). Where 90% is removed (harvested and bottled) and the remaining 10% is added to fresh sugar and tea and the fermentation process is “CONTINUED” .


Versus the Continuous Brewing Method, where the fermentation goes through this ebb and flow on a 24 or 48 hour clock rather than the 9-14 days. Instead of a huge reboot of 90% fresh sugar and tea, Its a smaller change of only 10-20%. The complete life cycle still exists except on a smaller bell curve.


The complete population cycle continues in either method.


In the CBM, you establish a larger bacteria/yeast population that is more comfortable in the reliability and consistently of its food and environment.. Kombucha like people are creatures of habit and do not do well with large sudden changes.


Back to Succession, as Michael Roussin pointed out many of the beneficial acids associate with Kombucha are not created until late in the “typical” cycle. Maybe in your brewing style you don’t like these “late comers” and why you feel CBM  does not taste as you would like it.  IMO,  CBM will taste just like any other Kombucha. But it is the artist in the brewer that can make a difference as well.


The “layering of these compounds”  which is what I believe Michael Roussin also referred to in support of CBM, you seem to imply (and correct me if I’m wrong) that it’s bad.  in your example of sauerkraut

“One would not throw a cabbage into a crock with only the last round of bacteria and expect it to yield the same delightful results as a ferment that has gone through all of the natural stages of complex fermentation. No no no.”

You’re expecting to ferment a full meal all at ounce. You are only throwing in a fresh percentage of “cabbage “ Typically 10% fresh food for a hungry 90% population. and then waiting the 24-48 hours.  CBM does work for sauerkraut - if you only pull off and add 10% daily. Not if you add 90% and expect it to be finished the next day.


Of course I have to say my CBM Kombucha does not taste like vinegar - to me.

Too much acetic acid (vinegar) can happen in any ferment. There are a couple of reasons for that.

the yeast are stressed out. Often caused by too high of a temperature. And that is dependent upon the species of yeasts Either

the yeast lack nutrition (Vitamin B12)

or the amino acids are lacking oxygen.

Weak bacteria. The Gluconobacter (one of 6 species of Acetobacter that produces gluconic acid and the Mushroom) are struggling. A less than perfect creamy smooth mushroom may be the first sign. Or by too vinegary taste. Gluconic acid balances out the harshness of acetic acid. Typically the Kombucha ferment will have about 30% more gluconic acid than acetic acid.

     Sometimes caffeine help stimulate the bacteria or the amino acid L-Arginine.


One problem more common to CBM is OXYGEN.

Where the bacteria are building their fortress (SCOBY / MUSHROOM)  with the purpose to suffocate the yeasts and to control their (the bacteria’s) environment.

When the yeast run out of Oxygen they stop Reproduction and go into Fermentation - cleaving the sugar into glucose to survive and alcohol is produced as their by product. The bacteria love alcohol and glucose (and caffeine too)  (like many men).


The lack of oxygen which results in a declining yeast population may lead to many problems - which may be what you are experiencing.  While too much oxygen plagues the ferment with off tastes and smells.


In all ferments “kombucha is a balancing Act” (Len Pozio )

The balance between the yeast and the bacteria. Be that in any method of fermenting Kombucha. Time and Temperatu

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