Lactofermented Apple Slices

When we shared that we were experimenting by fermenting apple slices in water, whey and salt, I was really curious what they would taste like.


It turns out that they taste like apples fermented in whey and salt.

This condiment isn’t for everyone.  I am positive we will find a great use for it but the initial flavor is bizarre (which makes it kind of fun).  There’s only a hint of the sweetness left to the apples, lots of tart from the whey and certainly a hint of salt.  I think I’ll soak some to see how the flavor transforms as well.

There are a few reasons to ferment apples like this:

  • To see what will happen.
  • To make an interesting condiment or ingredient.  I’m thinking that these could go very well as part of a marinade or put into a hot and sour soup or perhaps some roasted squash.
  • The process adds healthy bacteria and enzymes to apples and keeps them preserved without killing them (like a sauce laden with sugar would).
  • Apparently (untested though believable), it makes apples more accessible to those on sugar-reduced diets (like diabetics) as the fermentation consumes the sugar.  This makes sense based on all I’ve read but I’ve never tested it.

We did two batches of 2 cups (1 pint) each – one with the skins on and one with them off.  how they looked this morning (the ones with the skins are still on the left):


The ones with the skins went soft, a little slimier and browned.  The ones without the skins stayed white and are remarkably crisp.  Skins-off is the way to go!

Here’s what you need:

  • 2 cups of peeled apples shaved into slices (I use a mandoline and core them with a small knife)
  • 2 tablespoons of whey (you can easily create your own by straining yogurt like this)
  • 1 tablespoon of salt
  • Non-chlorinated water (if your tap water is chlorinated, let it sit in a wide bowl on your counter for about an hour)


  1. Toss the salt with the apples in a large bowl.
  2. Pack a clean mason jar with the apples.  Use large slices last and wedge them in the thin opening to stop them from floating.  We stop fruit and veg from floating all the time like this and call it seatbelting.
  3. Add the whey.
  4. Top with water, tapping to remove air bubbles.
  5. Place in a warm spot for 3 days.  I like to crack the seal slightly each day but an airlock is fine (in fact, one of these mason jar airlocks would work great and would eliminate the threat of too much pressure building up).  When I opened one jar the pressure was so high that I got sprayed with the contents.
  6. Move to a shady or dark part of the house (room temperature is fine) and let it sit for 1-3 weeks, tasting as often as you would like.
  7. To slow (and almost stop) the fermenting, place the jar in the fridge.

We’ll work on some recipes and see what uses we can find for this.  It’s a little powerful by itself but I’m convinced we can find an outstanding use for it in something!  What would you use it for?

Leave a Reply

  1. I’ve had good luck making a relish with apples, celery, garlic & onion…
    You need taste-o-vision to help us follow along with that one : )

    The real question is will you do it again?

  2. I like the look of the one with the skins on best. Hope to be gearing up for a big garden and lots of canning this fall…

  3. Hi there! Just wondering if you knew what propose the whey has. I don’t consume dairy and I wonder if I could replace the whey with something else, or forgo it entirely. Thanks!

    • you don’t need whey. if you want a starter to accelerate your fermenting, you can use liquid from sauerkraut or fermented (kosher) pickles,(unpasturised).don’t need much, just add it to your brine. you actually don’t need a starter. i made dill pickles , hot sauce and fermented snap peas with only 3.5% brine, no starter. takes a few days longer, but the stuff came out great! for some excellent reference and recipes Real Food Fermentation by alex lewin,and The Joy Of Pickling by linda ziedrich.

  4. How about a chutney? The salsa idea from mcjj also came to mind. I’ll be interested to read what recipes you come up with.

  5. low carbing diabetics have a few recipes for this sort of thing over on the Bernstein forum. I’ve seen one for a fermented apple pie with a low carb (amond and coconut flour) crust

  6. If you don’t want to or can’t use whey … Just leave it out. The whey is just an insurance policy to make sure the right kind of bacteria is where it needs to be at the right time. For a similar dairy free insurance policy try to ferment cabbage for 6 – 10 days and use some of that liquid to innoculate your fermented apples.

  7. Hi Joel,

    Very interesting idea! I was wondering, do you have any idea of how much of the original sugar was fermented in the process? Or can you give a rough estimate of how big a percentage of the sugar is normally fermented with something like apples which are high in fructose?

    Best regards,


    • Hi Rickdale,

      There are a lot of variables at play (temperature in the kitchen, amount of salt, length of ferment, relative moisture in the peppers, heat of the peppers in a given year and more) which make it difficult to quantify with any authority. I’ve made a significant amount of hot sauce – with and without whey – and not sure there’s a difference that could be detected without significant side-by-side testing but here’s my best shot at two differences:

      1) Whey can produce a bitter/sour flavor (vs traditional fermentation which is typically an emphasis on sour). It’s not overly bitter (like an IPA) but slight bitterness is present.
      2) Whey adds bacteria and speeds up the ferment. Many argue that a fast ferment is less sour. I’d argue that whey would therefore make your ferment less sour.

      If you’re fermenting dried peppers (we have two recipes on our site that do), whey also helps kickstart fermentation if other ‘good’ bacteria is absent.

      Hope that helps?


  8. I’ve just started fermenting and recently made a batch of lemons. I ground all the contents of the container (skins, seeds, liquid) to a paste in my vitamix, which I leave out on the counter (some is in the refrigerator). I toss cubed raw apples with a mix of lemon paste and whey, transfer them to a glass jar, leave them out on the counter overnight, bring them to work the next and eat them for lunch. I recently tried this with clean chopped fresh spinach, and some soaked and cooked cracked wheat. I can’t seem to get enough of the cultured lemons — they are incredibly delicious on everything they touch. I spoon it on top of bland cold white chicken breast (cooked); for a tangy salad topping. My question concerns safety — how does one really know when something is producing “bad” bacteria? So far, no one has been ill in my house from my experiments.

    Any help is appreciated


  9. I am fermenting cabbage and apples in brine, not whey. The apples at the top of the jar are brown. Is that ok to eat? I am on day 4 of this fermentation.