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Is Fermented Juice Safe To Drink?

A common question I get is whether or not a ferment is safe to consume. I’ve received this question so many times that I feel it’s time to make a post about it. One of the most commonly asked questions is if fermented juice is safe to drink. Here are my thoughts.

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Are Spontaneously Fermented Juices Safe To Drink?

No, fermented juice is NOT safe to drink.

My response assumes you are asking because your juice spontaneously fermented. As in, you did not set out to make a fermented drink.

Instead, you bought some grape juice or pineapple juice, and it stayed in the fridge too long and now it’s bubbly and fizzy. Or maybe it’s the orange juice you’ve been drinking for the past week. You forgot to put it back in the fridge for several hours, and suddenly it’s got some bubbles and a tang.

You know that people purposefully ferment drinks to make natural, probiotic sodas, so you’re wondering if this is the same general idea.

The answer is no, it couldn’t be farther from the same thing.

What happens when juice ferments spontaneously?

When juice ferments spontaneously, often it is due to contamination with bad bacteria. This is particularly the case if it is a pasteurized beverage, because all the good bacteria has already been killed.

But even a raw juice that spontaneously ferments isn’t necessarily safe to drink. It could be tainted with harmful bacteria such as E. coli or salmonella and make you very sick.

Bacteria and yeasts gobble up the sugars in the drink and release gases and ethanol. It results in a drink that is bubbly with a low alcohol content. This drink should be regarded as spoiled.

I’d avoid whether the juice was pasteurized or raw.

And when anyone asks me if “randomly” fermented drinks are safe, I will always say NO. Of course some will choose to drink them and things may turn out OK. But I would never advise it.

Drinking spontaneously fermented beverages can make you sick.

What’s the difference between a spontaneously fermented drink and a lacto-fermented drink?

Spontaneously fermented drinks are not created under any kind of controls. It is generally due to products being kept at too warm of a temperature, or not being used within the designated period of time. Generally juices recommend keeping them under refrigeration, and discarding within 7-10 days of opening.

Intentional fermentation is the complete opposite. When you intend to ferment, you put the juice in the right environment to ensure a safe end product.

Lacto-fermented drinks almost always contain a starter. If they do not, such as beet kvass, they are still fermented under controlled environments, generally with salt added to help stunt growth among harmful bacteria and allow lactic acid bacteria to flourish.

I personally also ferment beet kvass and similar ferments under anaerobic conditions, which also greatly decreases the odds of promoting the growth of bad bacteria and yeasts.

When fermenting fruit juices, I generally use a starter such as ginger bug or water kefir. These starters quickly drop the pH of the juice and crowd out any bad bacteria that may be in it. The starters help good bacteria flourish in the fermented juice, and have a preserving effect.

Even when home brewers are fermenting wine/alcohol, they will generally add something to kill the natural cultures before adding their own yeast.

Have you ever decided to drink spontaneously fermented juice? What has YOUR personal experience been? Leave a comment to let us know!

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Saturday 8th of January 2022

I accidentally drank apple juice that was never put in the fridge after two days of being opened and felt so sick an hour after vomiting and still 24 hours later having a sore stomach after eating or moving around on and off do not recommend haha


Tuesday 16th of November 2021

I accidentally drank a glass of orange juice that was sitting out in a cup for 30 hours. I thought it was water when I got up late at night. I immediately gagged and had acid reflux. It was not good times.


Friday 22nd of October 2021

I regularly drink Trader Joe’s fresh Tangerine Juice after it has unintentionally fermented in the refrigerator. Delicious!


Sunday 17th of October 2021

Hi, I have fresh grapes trying to make grape juice, this time I left the juice outside little bit longer. Now the grape juice is bit fizzy. Is it still safe to drink it? If not can I use it to make vinegar? Thanks


Tuesday 12th of October 2021

I have pomegranate seeds that have been in the refrigerator for six days that are just starting to turn. Are they still safe to eat?