Can I Ferment Fruit, Or Is It Just For Veggies?

“I’ve been trying my hand at fermenting veggies for a few months now—pickles and sauerkraut mostly, and they’ve turned out great! But now I’m wondering… can I ferment fruit too? I love the idea of expanding my preserving methods and not letting anything go to waste, but I’ve had a few failures with berries going bad. The last batch of strawberries I tried fermenting developed mold after a week and smelled terrible! Any advice on what went wrong, or if maybe fruit is just tougher to ferment? I’m based out in Wellington, and any tips for wholesale fruit fermenting would be great.” Thanks, Matt, Wellington, New Zealand.

Can I Ferment Fruit, Or Is It Just For Veggies?

Hey Matt! What a great question—and trust me, you’re not alone in wondering about this. Lots of folks get comfortable with fermenting veggies like cucumbers, cabbage, or carrots and then look at their fruit bowl and think, “Hmm, could I ferment *that* too?” The short answer is: Yes, you absolutely can ferment fruit! However, it does come with a few extra challenges compared to veggies. But don’t worry, it’s totally doable, and I’ll walk you through the process so you can start experimenting with fruit fermenting in no time!

Why Ferment Fruit?

One of the cool things about fermenting fruit, aside from the fact that it expands your preserving options, is the amazing flavor you can get. The natural sugars in fruit ferment differently than the sugars in vegetables, often producing a unique tang and sweetness at the same time. Plus, fermented fruits can be incredibly healthy, teeming with probiotics that are great for gut health—just like their veggie cousins.

That said, fruit is a little sweeter, softer, and more prone to spoilage than most veggies, and because of these quirks, it takes a few extra precautions to get it right.

How Does Fermentation Work With Fruits?

Matt, the fermentation of fruit is similar in principle to fermenting vegetables. You’re creating an environment where beneficial bacteria (usually lactobacillus) thrive while harmful microbes are controlled. These bacteria consume the sugars and starches in the fruit, producing lactic acid, which acts as a preservative and gives fermentation its signature tangy flavor. But because fruit contains more natural sugar than veggies, you might end up with a bit more alcohol production or even a carbonated end product (like a fizzy fruit drink) if it goes for longer.

Here’s the thing, though—the sugar content in fruit can speed up the fermentation process and lead to things getting off track more easily than with veggies. But, when done right, fermented fruits can be a sweet, tangy, and probiotic-rich addition to your meals. They’re great in smoothies, over yogurt, or even as a snack on their own!

Popular Fruits to Ferment

While you can *technically* ferment any fruit, some are more commonly (and successfully) fermented than others. If you’re just starting out with fruit fermentation, consider trying one of the following:

• Apples: Apples ferment wonderfully and can result in a fizzy, tangy snack or drink. Apple cider vinegar, for example, is the result of apple fermentation.
• Pineapple: Pineapples have a strong, sweet flavor that stands up well to fermentation, often producing a slightly fizzy, tropical result. Tepache (a Mexican fermented pineapple drink) is a favorite among home fermenters.
• Berries (with caution): Strawberries, blueberries, or raspberries are great to ferment, but because they are more delicate, they’re prone to mold if not prepped properly.
• Peaches and Pears: Some of my absolute favorites, these fruits develop a delicious, almost jammy consistency when fermented!
• Cherries: Keep those pits in, and fermented cherries become a delicious, slightly boozy treat—perfect for continued preserving or eating directly.

Now Matt, you mentioned trying strawberries and were met with… less-than-great results. Let’s talk about why that might have happened and how you can avoid it next time.

What Went Wrong With Your Strawberries?

Strawberries (along with other high-water-content berries) are notorious for being a bit finicky when it comes to fermentation. They’re soft and more vulnerable to mold, so it’s not uncommon for folks to run into trouble with them. Your issue sounds like it could have been due to a couple of factors.

1. Too Much Oxygen Exposure

Fermentation is an anaerobic process, meaning the fruits need to stay under the liquid where oxygen can’t reach them. With softer fruits like strawberries, they tend to float to the top pretty quickly, exposing themselves to air and increasing the mold risk. If your fruits are peeking above the liquid line, that’s probably when bad bacteria took over.

2. Temperature

Depending on the temperature in Wellington when you were fermenting, it could be that things got a bit too warm. A temperature above 70°F (21°C) can accelerate fermentation quite a bit—in fruits’ case, this often means they can slip into the funk zone, developing off flavors or molding faster.

3. Not Enough Salt

Using too little salt can also increase your chances of mold, because a fermentation brine works not only to draw moisture out of the fruit but also to create an inhospitable environment for harmful bacteria. Make sure you’re following the correct ratio of salt to water so that the salt can do its job of protecting your ferment.

Fermenting Fruit Safely: Top Tips

Now that we’ve covered why fruit can be a little tricky, let’s go over some important tips to make sure your next batch of fruits ferments properly, Matt:

1. Use Enough Salt

As we just touched on, salt is key in keeping out bad bacteria. For fruit ferments, you generally want to use about a 2-3% brine solution:

• For every 1 liter of water (about 4 cups), use 20 grams of salt.
• If you want a sweeter finish or less salty flavor, consider using honey or sugar *along* with your salt to balance things out.

2. Keep the Fruit Submerged

This is a general rule of thumb with any ferment, but it’s especially key with fruit. Since fruits are naturally buoyant, they tend to float above your brine. Weigh them down using a fermentation weight, a small plate, or even a clean cabbage leaf (I know, strange combo but it works!). Just make sure whatever you’re using keeps them fully submerged.

3. Ferment in Small Batches

Fruits, especially delicate ones like berries, are prone to spoil over long fermentation periods. It’s a good idea to ferment them in smaller, more manageable batches, reducing waste if anything does go wrong. Smaller batches also finish fermenting faster, so you’ll have your goodies sooner!

4. Watch the Temperature

If you’re in a warmer climate—New Zealand summers, for example—you might need to make sure your ferments are kept somewhere cool (under 70°F/21°C) to slow down the process. If the temperatures get too high, fermentation can accelerate, and your fruit can over-ripen or turn alcoholic quicker than expected.

5. Sweetener Balance

Fruits are naturally sweet—which means they are more likely to turn into alcohol if fermented too long. If your interest is in keeping the probiotics at the forefront and away from turning it into boozy fruit, try fermenting for just a few days (3-5 days) and then refrigerating the batch to stop the process. Fruits ferment much faster than veggies, so shorter times are cleaner unless you’re aiming to make a fruit wine!

How Long Will Fermented Fruit Last?

Fermented fruit will keep in your fridge for several months once properly fermented—sometimes even up to a year! Berries generally last less time than hardier fruits like apples or pears. The key is how well they’ve been fermented and how well they stay stored and submerged in their brine.

Common Troubleshooting for Fermenting Fruit

Let’s go through a couple of troubleshooting tips that every fruit fermenter should know:

1. Mold on the Surface

If you see a bit of white mold on the surface, it might just be kahm yeast, which is harmless! You can scoop it off and simply continue fermenting. However, if you see fuzzy or colorful mold that’s black, blue, or pink, unfortunately, that batch has turned. Toss it out and try again with a fresh batch.

2. It’s Too Sweet

If your fruit ferment tastes sweeter than you like, it’s possible that it hasn’t fermented long enough for the bacteria to turn those sugars into lactic acid. Try leaving it out at room temp for an additional few days, tasting periodically to catch it at just the right flavor.

3. It’s Too Sour

On the flip side, Matt, if you find the fruit ends up too sour, you can slow the process down by popping the ferment in the fridge sooner. Some people love the tang of super-sour fruits, but if it’s too much for your palate, check your ferment early (day 3 or 4) and chill it!

Great Uses for Fermented Fruit

Once you’ve got your fruit perfectly fermented, there are so many ways you can enjoy it! Here are a few fun ideas:

• Breakfast Topping: Add spoonfuls of fermented fruit to your yogurt, oatmeal, or granola for an extra probiotic boost.
• Smoothies: Toss a few pieces (along with a bit of brine) into your smoothies. Fermented fruit blends perfectly with fresh ingredients for a gut-healthy treat.
• Sauces: Fermented apples or pears can be blended with a bit of honey for a tangy, sweet sauce that pairs great with roast meats or pancakes.
• Adult Beverages: You can use some leftover fermented fruits to make a delicious sparkling beverage or fruity cocktail!

Final Thoughts…

Matt, thanks so much for sharing your experience—it’s always refreshing to see someone eager to experiment! Fermenting fruit is just as rewarding (and occasionally head-scratching) as fermenting veggies, but with the right approach, you can absolutely master it. Keep an eye on your salt levels, your temps, and make sure those fruits stay well-covered under the brine. You’ll be whipping up jars of probiotic-rich goodies in no time. Happy fermenting and don’t be afraid to try again!