Fermented bananas are easy to make and delicious -- they taste tart and sweet, with an added fizziness. They're also teeming with good bacteria.

So I’ve been kind of obsessed with fermenting these past couple of months. I started with the most basic kind that’s super easy to do — fermented cabbage (sauerkraut).

That turned out well.

So well in fact that I’ve been on roll ever since.

After the fermented cabbage, I experimented with fermenting:

  • onions, chilies and garlic to make a type of spicy raw pickle (not bad, but hard to eat eventhough I love spicy food)
  • crushed grapes and berries (great on yogurt, which makes it “probiotics-on-probiotics”)
  • ginger beer (still fermenting and bubbling cheerfully in my cupboard as I write this, but smell tests are promising)
  • sliced bananas (my most delicious success!)

Bananas! They can be fermented!

I was actually really reluctant to try fermenting bananas at first. I was sure that trying to ferment starchy bananas would lead to them rotting instead.

This might have to do with my fertile imagination or the fact that not much has been written about them (compared to other fruit ferments).

But even though I was sure it’d turn out to be a total failure, I still tried it out of curiosity.

Boy, am I glad I did!

Because fermented bananas has been my most delicious ferment yet. They’re tart, fizzy and slightly sweet. The smell is wonderfully banana-y.

And you know the “dry tongue/mouth” feeling you get when you eat fresh bananas? Well, with fermented bananas, that doesn’t happen. I’ve gotten very moist and soft slices, almost like they’ve been cooked slowly.

That’s the magic of good bacteria — those little guys have pre-digested my bananas to culinary perfection. And I didn’t even have to pay them 🙂 All they craved was the sugar in my bananas.

How I ferment bananas

The first time — MacGyvering it

The first time, I only used one banana. Yup, just one. I was so sure it won’t turn out well that I didn’t want to waste more.

What I used:

  • 1 banana
  • 1 tall, clear glass
  • a pinch of sea salt
  • 1 teaspoon of brown sugar
  • 1 probiotic capsule
  • a bit of cling film and a rubber band

The super simple steps 

  1. I cut the banana into medium slices.
  2. I half-fill a tall, clear glass (cleaned well) with dechlorinated water that is room temperature. (Declorinated water is not as fancy as it sounds, it’s just tap water that’s been left standing in a jug on my counter for at least 24 hours. The time lets the chlorine in the tap water evaporate. )
  3. I add a tablespoon of good brown sugar (demerara), a generous pinch of real sea salt, and the powder contents from 1 probiotic capsule (this acted as my starter).
  4. Stir this solution well.
  5. Then I plop the sliced bananas into the glass, leaving about 1-1.5 inches of room at the top. The extra room is needed because the ferment will expand and rise.
  6. Finally, I covered the top with a bit of clingfilm and held it in place with a rubber band around the mouth of the glass.
  7. Left this to sit in a dark cupboard for 5 days.
  8. Eat!

The smell test

On the fifth day, I took the cling film off and took a whiff.

This is “the smell test “. That deciding moment when you know whether a ferment has turned out well (i.e. the good bacteria won) or has gone off (i.e. the bad bacteria/yeast/mold won).

It smelt good. Really good.

I ran with the glass to the kitchen, got a clean spoon, scooped up the top slices and popped them into my mouth.

Oh yeah… they were good alright.

The top slices had turned a little brown and were mushy, but they still held together as a banana slice. It hadn’t turned into pulp. And the slices below the top ones were still yellow, but mushy as well.

I got a dish of plain yogurt and scooped out another spoonful of my fermented banana slices over it, which made for a lovely snack. And I felt good eating it because I knew it was healthy.

I MacGyver-ed my first banana ferment and it turned out fabulous.

The second time — more bananas and a larger container

The day I tasted my first banana ferment, I went out and bought more bananas because I was out. That’s how much I liked them.

For my 2nd attempt, I used pretty much the same stuff as in my first ferment, but:

1) I increased the amount of sugar and salt in proportion to the bananas and water. About 1 rounded tablespoon of brown sugar and 1/3 teaspoon of sea salt (Note: if your ferments turn out well and your starter is good, you can use less salt or none at all. When I was confident that I had a strong starter to start every new batch with, I left out the salt completely).

I used enough dechlorinated water to leave some room (but apparently not enough) and as many banana slices as I could fit.

2) I used a bit of the liquid left from my first ferment as my starter (instead of a probiotic capsule).

3) And instead of a glass, I used a large, wide jar with a locking lid. These jars are pretty easy to find. But you can use any clear glass container with a good lid.

The reason glass is used (and not plastic) is because ferments will grow increasingly acidic as they progress. And any acidic liquid can corrode plastic and leech dangerous toxic chemicals into itself. This is also why vinegar is sold in glass bottles at the supermarket.

This time, I left it in my cupboard to ferment for only two days.

Over two days, my bananas fermented and bubbled (as ferments do).

But there was SO much more “activity” compared to my other ferments.

Everytime I popped the lid open to do my smell test, more bubbles would appear and burst through the surface.

I’m not sure why, but the bubbles made me quite gleeful 🙂

I wanted to throw my arms up and yell, “It’s aliveeee!!!”

For the record, I did not do that.

A much faster ferment — just two days

I think the bananas were fermented much more quickly on my second attempt because the leftover liquid from my first ferment (5 days long) proved to be a much better starter than a probiotic capsule.

I would imagine that probiotic capsule powder would need to re-hydrate before the bacteria can propagate. But the leftover fermented liquid was already very active (and the nutrient-rich water was already an ideal environment for all that good bacteria).  

If you’ve tried fermented bananas, let me know how you like them!

UPDATE: I’ve been continuing with my banana ferments and my favourite bit now is drinking the liquid. It’s tart, fizzy and slightly sweet and sour, and really refreshing when served cold.

Also, the cooler weather has definitely passed and it’s been *really* hot and dry these days. Because of this, my bananas have been fermenting faster than ever. They’re done in about 12 hours or so — no kidding. When I get stubborn and leave them for a full day (>24 hours), they get fairly alcoholic and lose almost all the sweetness. 

Temperature matters a lot. If you live in a hot climate, you might want to shorten your fermentation too.