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Sugar-Free Kumquat Marmalade

4.8 stars, average of 29 ratings

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This low-carb kumquat marmalade is deliciously sweet, tart and chunky with hints of vanilla, ginger and cardamom. And it's really easy to make! You won't need to use any thickeners — no chia seeds, gelatin or pectin needed!

What Are Kumquats?

Kumquat is a fruit with sweet, edible skin and tart, sour flesh. They are now in season and when used for marmalade, they have the perfect chunky texture with delicate flavor.

To add more flavor I used a combination of ginger, vanilla and cardamom which go really well together. I found most of these tips in the Flavour Thesaurus book which has been really helpful for my recipe development!

How to Make Low-Carb Marmalade

Making low-carb marmalade is easy! You'll only need kumquats, low-carb sweetener, water, spices and a pinch of salt — that's it.

You'll need to slice all the kumquats and remove the seeds. This may take some time as there will be plenty of seeds. Once you do this, you will add all of the remaining ingredients and let the kumquats sit to soak. Finally you'll cook it all on low-medium until soft and syrupy.

Thick Marmalade Without Sugar

In this recipe you will need Allulose — no substitutions! I'm using granulated Allulose although Allulose syrup can be used instead.

Ever since I discovered Allulose, I knew I needed to make marmalade. Allulose is the perfect low-carb sweetener that works and tastes just like sugar but with none of the blood sugar spikes and calories. Other low-carb sweetener options simply wouldn't create that perfect syrupy texture.

There are a few Allulose options available on Amazon. The brand I use and like is RxSugar. If you live in the US you can get RxSugar 20% off by using this link (affiliate link) or by using the code KETODIET20 at checkout.

How Long Can I Store Homemade Marmalade for?

You can store this low-carb marmalade in a sealed jar in the fridge for up to 2 weeks. To preserve for longer, freeze or use the water-bath canning method.

Recipe Tips and Substitutions

Kumquats can be replaced with thinly sliced citrus fruits such as organic oranges, or a combination of oranges and lemons or tangerines.

If you can't get Allulose and need to use an Erythritol-based sweetener instead, you will need to add some gelatin (powder or sheets) to make it thicker, just like I did in my Chunky Low-Carb Strawberry Jam recipe. In this recipe I used gelatin sheets to replace part of the sweetener which would otherwise make the jam too sweet.

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Hands-on Overall

Serving size 1 tbsp, 20 g/ 0.7 oz

Allergy information for Sugar-Free Kumquat Marmalade

✔  Gluten free
✔  Dairy free
✔  Egg free
✔  Nut free
✔  Nightshade free
✔  Pork free
✔  Avocado free
✔  Coconut free
✔  Fish free
✔  Shellfish free
✔  Beef free

Nutritional values (per serving, 1 tbsp, 20 g/ 0.7 oz)

Net carbs1.7 grams
Protein0.3 grams
Fat0.1 grams
Calories12 kcal
Calories from carbs 75%, protein 12%, fat 13%
Total carbs2.7 gramsFiber1 gramsSugars1.4 gramsSaturated fat0 gramsSodium7 mg(0% RDA)Magnesium3 mg(1% RDA)Potassium28 mg(1% EMR)

Ingredients (makes about 620 g/ 1.4 lbs)

  • 450 g kumquats, sliced and seeds removed (1 lb)
  • 1 cup granulated Allulose (200 g/ 7.1 oz)
  • 2 tsp grated fresh ginger
  • 1/2 tsp vanilla bean powder or 1/2 tbsp sugar-free vanilla extract
  • 1/4 tsp ground cardamom
  • 1 cup water (240 ml/ 8 fl oz)
  • pinch of sea salt


  1. Wash the kumquats and slice them thinly. Remove any seeds, there will be plenty. Sugar-Free Kumquat Marmalade
  2. Place the sliced kumquats in a saucepan (pouring any juice from the chopping board). Add Allulose, ginger, vanilla, cardamom and salt. Pour in a cup of water. Allow the sliced kumquats to sit for 30 to 45 minutes.
    Note: Do not use any substitutes for the allulose as the syrup won't thicken with alternatives. If you can't get Allulose, see recipe tips for modifications. Sugar-Free Kumquat Marmalade
  3. After 30 to 45 minutes, place on the stove and bring to a boil over medium-high heat. Sugar-Free Kumquat Marmalade
  4. Reduce the heat and simmer on medium-low for 25 minutes, or until softened and syrupy (jam-like consistency with chunks of kumquats). Sugar-Free Kumquat Marmalade
  5. Transfer the marmalade into a large glass jar (or more smaller jars) with a tight-fitting lid.
  6. This marmalade will keep in the fridge for about 2 weeks. It can be frozen for longer storage or preserved using the water-bath canning method. Sugar-Free Kumquat Marmalade

Ingredient nutritional breakdown (per serving, 1 tbsp, 20 g/ 0.7 oz)

Net carbsProteinFatCalories
Kumquats, raw
1.4 g0.3 g0.1 g10 kcal
Allulose, natural low-carb sweetener
0.3 g0 g0 g1 kcal
Ginger root, fresh
0 g0 g0 g0 kcal
Vanilla extract, powder (vanilla bean)
0 g0 g0 g0 kcal
Cardamom powder, spices
0 g0 g0 g0 kcal
Water, still
0 g0 g0 g0 kcal
Salt, sea salt
0 g0 g0 g0 kcal
Total per serving, 1 tbsp, 20 g/ 0.7 oz
1.7 g0.3 g0.1 g12 kcal

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Martina Slajerova
Creator of

Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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Comments (2)

Hi Martina,
I made sugar-free kumquat marmalade earlier this year with a different recipe.  It was delicious but I could not get it thick and when it cooled it crystalized.  I soon found out that allulose is CRITICAL to this recipe and does not crystalize upon cooling nor does it have that cooling effect.  Its the perfect sweetener for this.  We have had a kumquat tree in our yard for a zillion years and just this year I decided to do something with them!  I bought another kumquat tree earlier this year so hopefully my crops will be plentiful!

I agree, Allulose is just amazing. You are so lucky, I love using anything that grows in my garden but no kumquat yet 😊
(I'm sorry for the delayed response, life gets busy with newborn twins!)