The complete guide to kombucha
Tea, sugar and a SCOBY. Everything that decides whether a kombucha turns out well: an acidic starter, pH measured twice and the fridge on time.
9 min read Getting good Reviewed October 26, 2026 72 facts, each with its source
What kombucha is
Kombucha is sweetened tea fermented by a SCOBY, a culture of bacteria and yeasts. It ferments in two steps: the yeasts turn the sugar into alcohol and gas, and the bacteria turn that alcohol into acetic acid1. That acidity is one of the things that hold back harmful bacteria2. The acid-making bacteria need air, so the jar ferments uncovered, with just a cloth over it3.
Fervida's recipe comes from a study by the University of Georgia and Kansas State4. It asks you to measure twice: the starter before you begin and the kombucha before it goes into the fridge.
The SCOBY and the starter
The SCOBY is the rubbery layer that grows on top of the tea5. It comes with its starter liquid, which is kombucha from an earlier batch. Virginia Tech recommends buying the first one and not passing SCOBYs from person to person6. The NCHFP, the National Center for Home Food Preservation, lists friends who brew kombucha among the places to get one7. Fervida follows Virginia Tech: buy the first one.
The starter provides the initial acidity that protects the tea while it gets going8. Before you start, measure its pH: it has to read 4.0 or lower9. Put a tablespoon in a cup, test it with a strip and throw that tablespoon out10. If it reads above 4.0, don't make kombucha with that starter11.
Virginia Tech asks for 10% starter12, and Fervida won't let it go lower: that is a house rule. The recipe uses 20%, which is what the NCHFP says to keep from each batch for the next13.
What you need
- A glass jar of about 6 liters (1.5 gallons). The recipe asks for a container of at least 1.5 gallons14.
- No ceramic, lead crystal or metal. Kombucha is acidic and can draw toxic elements out of the container15. Glazed pots have caused lead poisoning16, and Virginia Tech asks for a container that isn't metal17.
- A paper towel, coffee filter or cheesecloth, with a rubber band18.
- A kitchen thermometer and a calibrated pH meter, the most reliable way to measure pH19. Strips are enough for the starter.
- A quiet spot, away from vents, busy areas and pets20.
Wash everything with soap and water, then sanitize it by submerging it in water at 77 °C (171 °F) or hotter for 30 seconds21.
Tea and sugar
The recipe uses 3.8 liters (1 gallon) of water, 6 black tea bags22, 13 green tea bags23 and 200 g (1 cup) of sugar. Any Camellia sinensis tea works: black, green, white or oolong24. Herbal teas may not, because some hold back the bacteria25. Use store-bought tea26; if you avoid caffeine, decaf works27.
Heat 950 ml (4 cups) of the water to 74–76 °C (165–169 °F) and steep the tea for 2 minutes. That meets both the NCHFP's 71–77 °C (160–170 °F)28 and Virginia Tech's above 74 °C (165 °F)29. Dissolve the sugar, add the rest of the water cold and check that the tea is below 35 °C (95 °F) before the SCOBY goes in30.
Use white granulated sugar: the recipe hasn't been tested with others31. 200 g in 3.8 liters is about 53 g per liter, one of the three concentrations in the study32. Don't make a half batch: with the same SCOBY it can turn out too acidic33.
7 to 10 days at 68–77 °F
Add the SCOBY with its starter, stir, cover with the cloth and write down the date: this is day 0. Leave it for 7 to 10 days at 20–25 °C (68–77 °F)34. Cooler slows it down and warmer speeds it up35. BCCDC, British Columbia's public health agency, puts the optimum at 20–22 °C (68–72 °F), with limits of 10 and 26 °C (50 and 79 °F)36.
Bubbles, a tangy smell and a new layer on the surface are good signs37.
pH: between 4.2 and 2.5
On day 7, measure the pH with the calibrated meter. It has to be 4.2 or lower38: that keeps in check the spores tea leaves can carry39. And never below 2.540, because that much acid can make susceptible people ill41. That's what the fridge is for: chilling it stops the acid as the pH nears 2.542. If it has already dropped below 2.5, don't drink it.
If it hasn't reached 4.2 by day 7, the culture is most likely contaminated or it's too cold. Throw it out and start again with a bought SCOBY43. Between day 7 and day 10, it's your call: more days make it more sour44.
Bottling, storing and starting over
Pour it into clean bottles or jars and put it in the fridge, at 4 °C (40 °F) or below: it keeps for up to 30 days45. The fridge holds back alcohol and excess acid46. If you seal the bottles airtight, keep an eye on them: gas builds up and they can explode47.
Set the SCOBY aside with 20% of the liquid for the next batch. If you won't start right away, the NCHFP leaves it in its jar, covered with the cloth, for up to 30 days48: in an airtight container the yeasts die and the next batch can fail49. Virginia Tech prefers to keep it in the fridge, covered in kombucha50; Fervida follows the NCHFP, whose recipe was tested. Either way, the liquid has to stay below pH 4.251.
Flavors and fizz
Flavor goes in once the kombucha has fermented52 and its pH is below 4.253. Once it's in, measure again: the mix has to stay below 4.2 and above 2.554. Don't add sugar55: sugar that goes into the bottle can make more alcohol if it keeps fermenting56. If you use juice, make it pasteurized and store-bought57. Once flavored, it goes in the fridge and is drunk within 2 days58.
To make it fizzy, it's bottled sealed and spends a day or two out of the fridge. The limits are house rules: bottles made for carbonation, a PET test bottle, 48 hours at most and 25 °C (77 °F) at most. "Carbonation and exploding bottles" explains them.
What can go wrong
| What you see | What it is | What to do |
|---|---|---|
| Dry, fuzzy patches, white or colored | Mold59 | Throw out the tea and the SCOBY, then wash and sanitize the jar |
| An uneven or lumpy new layer, with no fuzz | The SCOBY, which doesn't always grow smooth60 | Nothing |
| Bubbles trapped under the layer | Fermentation at work61 | Nothing |
| A SCOBY that sinks and doesn't rise again | A culture that isn't working well62 | Measure the pH: if it won't reach 4.2, throw it out |
| pH above 4.2 on day 7 | A contaminated culture, or too cold | Throw it out and start with a bought SCOBY |
How much, and for whom
Virginia Tech asks that the label on kombucha for sale advise no more than 120 ml (4 oz) a day63. The NCHFP doesn't advise it for people with weakened immune systems, pregnant women, children or anyone with certain health conditions64. And BCCDC warns that excess acid can cause acidosis in people with an underlying condition, especially a metabolic one such as diabetes65.
It also contains alcohol. With the NCHFP recipe and the fridge on time, it stayed at trace amounts, under 0.016%66. But in another study, cited in a review, kombucha reached 0.78% on day 7 and 1.10% on day 1067, and the more days it ferments, the more alcohol it makes68. That's why it's not for young children or during pregnancy69. How much it has, and what makes it rise, is in "Alcohol in kombucha and kefir".
The recipes
- Homemade kombucha: the tested recipe, with black and green tea. The starting point.
- Jun: kombucha made with green tea and honey70. It ferments faster, in 4 to 7 days71. Because it has honey, it's not for babies under 12 months72.
- Ginger lemon, berry, pineapple mint, hibiscus and apple cinnamon: second fermentations of homemade kombucha, in the bottle and with their own time limits.
Where every number comes from
Every number in the text leads to its figure: the exact sentence from the official guide it comes from, in its own language.
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1
Yeasts make alcohol and gas, and bacteria turn the alcohol into acetic acid
“In the first step, the yeast in the SCOBY ferments the added sugar and forms alcohol and carbon dioxide. In the second step, the bacteria in the SCOBY ferments the alcohol to produce vinegar (acetic acid).”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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2
The acidity of finished kombucha helps hold back harmful bacteria
“The resulting acidic environment of fully brewed kombucha is one of the characteristics that help prevent harmful bacterial growth.”
University of Georgia Cooperative Extension · What’s the Word on Homemade Kombucha? (Circular 1312, 10-apr-2026) · read on October 20, 2026
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3
It ferments uncovered, because the acid-making bacteria need oxygen
“Vessels should be uncovered (not closed) during fermentation as AABs are aerobic and require oxygen for conversion of alcohol to vinegar.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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4
Recipe researched by the University of Georgia and Kansas State
“This research was conducted as a collaboration between University of Georgia Food Science and Technology, Kansas State University Food Science Institute, and University of Georgia Nutritional Sciences.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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5
The SCOBY forms a mat on top of the tea
“The SCOBY will form a mat (pellicle) on top of the fermentation vessel.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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6
Virginia Tech: buy the first SCOBY, and don't pass it from person to person
“It is highly recommended that you purchase your SCOBY commercially for first use. Do not pass SCOBY cultures from one person to another.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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7
The NCHFP lists friends among the places to get a SCOBY
“SCOBYs can be obtained from various sources, including local kombucha brewers, online marketplaces, health food stores, or through friends who brew kombucha.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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8
The starter liquid provides the initial acidity
“This provides an initial acidity necessary for the safety of the product”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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9
Starter liquid at pH 4.0 or lower
“Verify that the starter liquid has a pH of ≤ 4.0.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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10
Test one tablespoon and throw it out
“If the pH is 4.0 OR LESS, proceed to step 4 of the instructions above, discarding the starter liquid that you tested.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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11
Above 4.0, that starter isn't used
“If the pH is GREATER THAN 4.0 do not make kombucha with the starter liquid.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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12
10% starter
“Add 10% inoculum (SCOBY)”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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13
Keep 20% of the liquid for the next batch
“After each batch, reserve 20% of the liquid and the SCOBY for the subsequent batch.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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14
A container of at least 1.5 gallons
“for our recipe at east 1.5 gallon food grade container”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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15
No ceramic or lead crystal
“Because of the acidity of Kombucha tea, it should not be prepared or stored in containers made from materials such as ceramic or lead crystal, which both contain toxic elements than can leach into the tea.”
CDC, MMWR 44(48):892 · Unexplained Severe Illness Possibly Associated with Consumption of Kombucha Tea -- Iowa, 1995 · read on October 20, 2026
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16
Glazed pots have caused lead poisoning
“Lead poisoning has occurred when inappropriate glazed containers were used to ferment highly acidic teas over time.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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17
A non-metal container
“Ferment in a non-metallic food grade container.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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18
Covered with paper towel, coffee filter or cheesecloth and a rubber band
“Dry the opening of the container, then cover with a paper towel, coffee filter, or clean cheese cloth and secure with a rubber band or string.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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19
A calibrated pH meter is the most reliable way to measure pH
“The most reliable method to measure pH is using a calibrated pH meter.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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20
Away from drafts, busy areas and pets
“Avoid placing your brewing vessel in areas with high air circulation, such as near vents or in busy spaces with lots of people and pets.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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21
Sanitize in water at 171 °F or hotter for 30 seconds
“Submerge cleaned equipment in hot water (at least 171°F) for at least 30 seconds to sanitize.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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22
6 black tea bags
“3 tablespoons (or 6 tea bags) black tea”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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23
13 green tea bags
“1/3 cup + 2 tablespoons (or 13 tea bags) green tea”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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24
Any Camellia sinensis tea works
“Steeped tea made from any variety of Camellia sinensis (black, green, white or oolong) is acceptable.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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25
Herbal teas may not work
“Herbal teas and infusions may not be acceptable if they contain compounds that interfere with natural fermentative bacteria”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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26
Commercially produced tea, free of contaminants
“Always use commercially produced tea to avoid contaminants that can harm the SCOBY.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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27
Decaf tea works
“You can still make your own kombucha and use the tested recipe by using decaffeinated versions of black and green tea.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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28
Tea steeped 2 minutes in water at 160–170 °F
“Heat 4 cups of water to 160° - 170°F (use a food thermometer to check), and add the tea to steep for 2 minutes.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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29
Virginia Tech: tea water above 165 °F
“Ensure that hot water (>165°F) is used to steep the tea.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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30
Below 95 °F before the SCOBY goes in
“Take the temperature of the tea to make sure it is below 95°F before proceeding to step 8.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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31
Other sugar types are not recommended
“It is not recommended to use other sugar types with our recipe.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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32
Tested with 26, 53 and 80 g of sugar per liter
“sugar concentrations of 26 g/L, 53 g/L, and 80 g/L”
Food Protection Trends (Cullinan et al., IAFP) · Determining Critical Food Safety Factors for Safely Homebrewing Kombucha: A Study on Microbial Survivability (2025) · read on October 20, 2026
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33
A half batch can turn out too acidic
“It's not recommended to make a half batch of kombucha. Doing so could lead to excessive acidity due to the same amount of SCOBY used”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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34
7 to 10 days at 68–77 °F
“allow the kombucha to ferment at room temperature (68° - 77°F) for 7 – 10 days.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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35
Cooler is slower; warmer is faster
“Cooler temperatures may slow fermentation, while warmer temperatures can accelerate it.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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36
Best at 68–72 °F, between 50 and 79 °F
“Optimal temperatures for fermentation are between 20°C to 22°C with an upper limit of 26°C and lower limit of 10°C.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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37
Bubbles, a tangy smell and a new layer are good signs
“Signs of proper fermentation include the formation of bubbles, a tangy aroma, and a slightly sour taste. A new SCOBY may also form on the surface of the liquid.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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38
pH 4.2 or lower, with a calibrated meter
“Monitor the pH with a calibrated pH meter during fermentation to ensure the product gets to ≤4.2.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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39
Below 4.2, spores from the tea leaves are kept in check
“The recommended pH of kombucha is below 4.2, to control for spores of B. cereus or C. perfringens that may be present on tea leaves”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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40
Never below pH 2.5
“To prevent the product from getting dangerously acidic, the pH should be no lower than 2.5.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
-
41
At pH 2.5 or lower it can make susceptible people ill
“Excess acids during prolonged fermentation, when pH is 2.5 or lower, can cause illness in susceptible individuals.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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42
As the pH nears 2.5, into the fridge
“This hazard is controlled by stopping the further development of acetic acid when the pH approaches 2.5.”
BC Centre for Disease Control, Environmental Health Services · Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan (2015, updated 2020) · read on October 20, 2026
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43
If it doesn't reach 4.2 in 7 days, throw it out and start with a bought culture
“If the pH does not reach pH ≤ 4.2 in seven days, the culture is most likely contaminated or the fermentation temperature is too cold. In either case, discarding the KT is recommended. Start a new batch with a newly purchased commercial culture.”
BC Centre for Disease Control, Environmental Health Services · Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan (2015, updated 2020) · read on October 20, 2026
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44
More days, more sour
“For our recipe, the fermentation process takes between 7 to 10 days, depending on desired tartness.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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45
In the fridge at 40 °F or below, up to 30 days
“kombucha should be stored in the refrigerator at 40 degrees Fahrenheit or below to slow down fermentation and preserve flavor. It can be stored under refrigeration temperatures for up to 30 days.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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46
The fridge holds back alcohol and excess acid
“Refrigeration limits alcohol and excessive acid production.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
-
47
Sealed airtight, it builds up gas and can explode
“Storing kombucha in airtight containers can cause the accumulation of CO2 (carbonation), potentially leading to an explosion if not regularly monitored.”
National Center for Home Food Preservation (USDA, University of Georgia) · Kombucha Tea · read on October 20, 2026
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48
The SCOBY keeps in its jar with 20% kombucha for up to 30 days
“The SCOBY can be stored in the fermentation vessel with about 20% of previously brewed kombucha for up to 30 days.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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49
In an airtight container, the yeasts die and the next batch can fail
“Using an airtight container may create an anaerobic environment, causing aerobic yeasts to die and potentially resulting in a failed next batch of kombucha.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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50
Virginia Tech keeps it in the fridge, covered in kombucha
“Refrigerate SCOBY in a covered, cleaned, and sanitized food grade container covered with kombucha liquid from the last batch.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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51
Reused culture kept below pH 4.2
“Make sure the pH of reused culture is maintained at <4.2 to minimize the risk of contamination from harmful bacteria.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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52
Flavor goes in once it has fermented
“Kombucha can be flavored after the fermentation process is done.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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53
With the pH already below 4.2
“Flavouring agents should be added after initial fermentation, when the pH has dropped below 4.2.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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54
Once flavored, between 2.5 and 4.2 again
“After juice or other flavouring agents have been added, the pH must again be tested to ensure the pH of the finished product is less than 4.2 but above 2.5.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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55
Don't add sugar to finished kombucha
“Don’t add more sugar to your kombucha to make it sweeter after it’s done fermenting.”
UGA Extension Forsyth County · Relax, Unwind, and Safely Make Your Own Flavored Kombucha at Home (11-jul-2025) · read on October 20, 2026
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56
Sugar in the bottle can make more alcohol
“Sugars and flavourings with added sugar added after this second step may cause formation of excess alcohol if fermentation persists.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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57
If you use juice, pasteurized and store-bought
“If juice is added for flavouring after the fermentation step, a pasteurized, commercially produced juice is recommended.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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58
Flavored, it goes in the fridge and is drunk within 2 days
“Once flavors have been added kombucha should be stored under refrigeration and consumed within 2 days.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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59
Dry, fuzzy patches, white or colored: the tea and SCOBY go
“If you see dry, fuzzy patches on your SCOBY and/or the liquid surface of the kombucha that are either white or colored, this is an indicator that the brew is spoiled. The tea and SCOBY should both be discarded”
University of Georgia Cooperative Extension · What’s the Word on Homemade Kombucha? (Circular 1312, 10-apr-2026) · read on October 20, 2026
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60
Mold is not to be confused with the SCOBY's uneven surface
“not to be confused with the sometimes irregularly shaped surface of the SCOBY”
BC Centre for Disease Control, Environmental Health Services · Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan (2015, updated 2020) · read on October 20, 2026
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61
Air bubbles are normal
“Air bubbles are normal and indicate fermentation taking place.”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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62
A SCOBY that sinks and stays down, or a pH that won't reach 4.2, means it's failing
“Additional indications of poor SCOBY pellicle function when finished product fails to each pH 4.2,23 and when pellicles sink to bottom of fermentation vessel and do not rise again.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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63
Virginia Tech: on the label, no more than 4 oz a day
“no more than 4 ounces per day is recommended”
Virginia Cooperative Extension (Virginia Tech) · What do I need to know to sell KOMBUCHA at the farmers market? (FST-297, last reviewed November 2025) · read on October 20, 2026
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64
Not advised for the immunocompromised, pregnant women or children
“it may not be suitable for those with compromised immune systems, pregnant women, children, or individuals with certain health conditions.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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65
Excess acid, a risk with metabolic conditions such as diabetes
“Acidosis from excess acid can occur in persons with underlying medical conditions, in particular metabolic issues such as diabetes.”
BC Centre for Disease Control, Environmental Health Services · Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan (2015, updated 2020) · read on October 20, 2026
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66
With the NCHFP recipe, trace amounts of alcohol
“By following our guidelines and recipe, your kombucha may have trace amounts of alcohol (<0.016 % alcohol by volume – ABV).”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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67
In another study, 0.78% on day 7 and 1.10% on day 10
“According to a separate investigation, the ethanol concentration reached 0.78% on the seventh day and peaked at 1.10% on the tenth day of fermentation”
Foods (MDPI), via PubMed Central · Kombucha Fermentation of Olympus Mountain Tea (Sideritis scardica) Sweetened with Thyme Honey (2023) · read on October 25, 2026
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More days, more alcohol
“Longer fermentation periods will produce more alcohol.”
University of Georgia Cooperative Extension (National Center for Home Food Preservation) · Crafting Kombucha at Home: Frequently Asked Questions (2026) · read on October 20, 2026
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May contain alcohol: not for young children or during pregnancy
“May contain alcohol. Not a suitable beverage for young children or during pregnancy.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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Jun is made with green tea and honey
“Kombucha is typically made with black tea and refined sugar, whereas Jun is made with green tea and raw honey.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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Jun ferments faster, in 4 to 7 days
“Jun ferments faster than kombucha. The primary fermentation usually proceeds for 4 to 7 days at 21-26 °C.”
BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.11: Kombucha and Jun (September 2023, updated December 2024) · read on October 25, 2026
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No honey for babies under 12 months
“Honey should not be added to water, food, or formula fed to infants under 12 months of age.”
UF/IFAS Extension · Infant Botulism and Honey (ENY-128/AA142) · read on October 25, 2026