How can I tell if my kombucha has gone bad?

**Fermentation Process**: Kombucha is created through the fermentation of sweetened tea using a SCOBY (symbiotic culture of bacteria and yeast).

During fermentation, beneficial bacteria produce acids, which can result in a tangy or sour flavor.

**pH Levels**: The pH of kombucha typically ranges between 2.5 and 3.5.

If it has a significantly higher pH, it may indicate spoilage or improper fermentation, leading to an increased risk of harmful bacteria growth.

**Mold Appearance**: Mold can develop if contaminants enter the brewing environment.

If you observe fuzzy, colorful patches on the surface, it is a strong sign of spoilage, and the kombucha should be discarded.

**Cloudiness**: While some cloudiness is normal due to yeast and other sediments, an unusual or excessive cloudiness, especially when paired with an off smell, can suggest spoilage.

**Off Smells**: Kombucha usually has a vinegar-like, tangy smell.

A foul or rotten odor is a strong indicator that the drink is no longer safe to consume.

**Taste Check**: Although kombucha often gets more acidic over time, if it tastes unusually harsh or unpleasant beyond the standard tartness, it may be an indication that it has gone bad.

**Change in Fizziness**: If previously fizzy kombucha has become flat, it could suggest that the fermentation process has gone awry, hinting at spoilage.

**Sediment Formation**: Natural sediment can form at the bottom of kombucha bottles as a result of yeast activity.

While this is normal, large clumps of sediment can indicate instability or fermentation issues.

**Pasteurization Effects**: Store-bought kombucha may undergo pasteurization, greatly extending its shelf life.

If your homemade kombucha lacks such treatment, it's generally more susceptible to spoilage.

**Storage Conditions**: Keeping kombucha at higher temperatures than recommended can accelerate spoilage.

Ideally, it should be stored in a cool environment, preferably in the refrigerator.

**Expiration Dates**: The “best before” date indicates quality rather than safety.

Kombucha may still be fine to consume after this date if it smells and tastes acceptable.

**Alcohol Content**: If kombucha starts to taste like alcohol, it may have fermented too long, which could indicate excess yeast activity that may not be safe for consumption.

**Observation of Bubbles**: Active carbonation is a sign that the fermentation is still occurring.

If the bubbles cease without a strong acidic flavor, it could suggest an imbalance, risking spoilage.

**Appearance of a Pellicle**: A pellicle, a film that forms on top of fermenting kombucha, is generally harmless and is composed of yeast and bacteria.

However, if it appears dark or fuzzy, it could indicate contamination.

**Health Risks**: Consuming bad kombucha could potentially lead to gastrointestinal distress due to harmful bacteria or excessive acidity, particularly for individuals with sensitive digestive systems.

**Brewing Environment**: Home-brewing requires a clean environment.

Improper hygiene can introduce harmful bacteria, undermining the brewing process and raising spoilage risks.

**Use of Non-Tea Ingredients**: Kombucha can be flavored with various fruits or herbs.

However, not all additions are safe during fermentation, as some could promote mold growth or destabilize the SCOBY.

**Diversity of Cultures**: Different SCOBYs can yield varying results based on the strains of yeast and bacteria present.

Some may ferment longer or shorter, impacting the final product's stability.

**Kombucha's Living Nature**: As a living beverage, kombucha continues to ferment even in the bottle.

This could lead to unpredictable changes in taste and safety if left unchecked.

**Microbial Dynamics**: The microbial composition of kombucha can change dramatically over time.

A once-safe batch may become dominated by harmful bacteria if fermentation conditions worsen or if left too long.