As an experienced sommelier and brewer, I can tell you that determining whether kombucha has gone bad can be a bit tricky. However, there are a few telltale signs that you can look out for to ensure that your kombucha is still safe to consume.
First and foremost, pay attention to the appearance of your kombucha. It should generally have a clear, slightly effervescent appearance, with a range of colors from pale yellow to light brown. If you notice any greenish or pinkish “stuff” floating in your kombucha, it is likely a sign of mold. Mold growth can occur when the brewing conditions are not optimal or if the kombucha has been contaminated. In such cases, it's best to err on the side of caution and discard the entire bottle to prevent any potential health risks.
Another indicator of spoiled kombucha is a foul or off-putting smell. Kombucha typically has a slightly sour, vinegary aroma due to the fermentation process. However, if you notice any strong, unpleasant odors like rotten eggs or a rancid smell, it could be a sign that the kombucha has gone bad. Trust your nose and if something seems off, it's best to discard it.
Taste is another important factor in determining the quality of kombucha. A well-brewed kombucha should have a balanced and slightly tangy flavor with a hint of sweetness. However, if you notice any significant changes in taste, such as an overly acidic or bitter flavor, it could indicate that the fermentation process has gone awry or that harmful bacteria or yeast have taken over. It's always better to be safe than sorry, so if the taste is off, it's best not to consume it.
Lastly, pay attention to the carbonation level of your kombucha. It should have a pleasant fizziness, similar to that of a lightly carbonated beverage. If you notice that your kombucha is completely flat or overly effervescent, it could be a sign that the fermentation process was not successful or that the bottle was not properly sealed. While this may not necessarily mean the kombucha has gone bad, it may affect the overall quality and taste.
When determining if kombucha has gone bad, keep an eye out for any greenish or pinkish mold floating in the liquid, foul or off-putting smells, significant changes in taste, and unusual carbonation levels. Trust your senses and if anything seems off, it's better to discard the bottle and purchase a fresh one. Remember, the quality and safety of your kombucha should always take precedence.