recipe notes
step-by-step method
recipe card
One of the things I enjoy about getting older is that as my taste buds change and evolve, foods that I once hated become new to discover. When I was five I was likely to claw your eyes out if you tried to feed me mustard, and now I’m likely to claw your eyes out if you deprive me of it. The same goes with grapefruit. I wouldn’t touch the stuff growing up but thankfully I’ve come to my senses and entered a regular ol’ grapefruit renaissance.
Just like certain foods in my youth, when I was a young cookling I had no interest at all in making jams and jellies. But now I’m a little older, a little wiser, and I’ve uncovered a whole new pastry world to embrace. So there you have it, love of grapefruit + love of making jam = grapefruit marmalade.
recipe notes
First and foremost, let’s clear up a terrible myth surrounding jam and jelly making – jam is not a destination for the fruit you wouldn’t otherwise eat. This is in the same absurd line of thinking that you should cook with wine that is too crappy to drink. Because – and I shouldn’t even have to say this – how in the f*ck can you expect to make good jam with fruit you wouldn’t want to eat?? The only fruit you should use for making jam is the best, cleanest, ripest most delicious fruit you can find.
To properly set your marmalade you’re going to need pectin. Although grapefruit (and all fruit) naturally has pectin in it, I use a commercial pectin too, which speeds the cooking process and preserves the brightness and natural acidity of the fruit. For some more in-depth talk on pectin and the science of making jam, I highly recommend you check out my post – food science: fruit preserves.
Monitoring the cooking temperature of the preserve is the first benchmark of knowing when it is ready to set. The preserve must reach a minimum temperature of around 221F/105C to have the potential to set as a gel. While it’s easy enough to use a thermometer to check the temp., a preserve at 221F/105C doesn’t always indicate a finished product, so it’s always a good idea to perform a “set test.” A set test uses a small sample of the cooked preserve and rapidly cools it to see if it has the properties of a finished gel. We’ll look at how it’s done in the method.
At the hotel, we use a lot of marmalade, so we just make it and keep it in big pans. Chances are, you’ll want to store your marmalade in canning jars. Ball jars are pretty standard issue for canning and jamming, and you can find just about any size you might want.
grapefruit marmalade
yield: approx. 80oz
You’ll notice this recipe is set up a little differently from most others. The weight of each ingredient will be a percentage of the total weight of your fruit (the same method used for baker’s percentages). I do this because the overall size, water content and solid content of your fruit can be wildly different from one day to the next. If I simply said to use “4 medium grapefruits” – the weight of your fruit would never be the same twice, and that’s no way to be consistent. When making this recipe, measure the weight of your fruit first, then measure everything else as appropriate by percentage.
ingredients
1000g grapefruit segments and juice (100%)
60g grapefruit zest (6%)
300g water (30%)
900g sugar (90%)
40g pectin (4%)
30g lemon juice (3%)
method
Before you get started, clean and sanitize the jam jars you plan to use. I like to run them alone in the dishwasher and keep them there until I need to use them. If the lids have a heat seal on them, don’t place them in the dishwasher or they won’t seal properly when you get them on the filled jars. Clean the lids with soapy water, dry them and keep them covered.
Prepare your grapefruit to determine your fruit weight. You’ll use this weight to measure out the remaining ingredients.
Using a peeler, remove the skin. Cut any excess pith from the peel (Carefully! Use a sharp knife and keep it controlled as you draw it toward your hand). Julienne the peels and reserve them for later.
Remove the tops and bottoms from the grapefruits, then cut the remaining rind from them, leaving as much of the fruit intact as possible.
Supreme the grapefruits. Using a paring knife, cut into each segment of fruit tight to the membrane separating the segments. Repeat the process on the opposite side of the segment to remove it. No need to attempt cutting pretty segments, it’s all going to break down during cooking anyway.
As you work with the grapefruits, save all of the membranes and seeds. They contain some of the precious pectin you’ll need for killer marmalade. Place the membranes in a strainer over a bowl while you work on segmenting the fruit. Once all of your grapefruits are segmented, take the membranes and squeeze every last drop of juice from them like they owe you money.
Add this juice to the segmented fruit and weigh it for the total fruit weight. You aren’t done with the membranes yet! Place the membranes and seeds together in a cheesecloth tied off with some butcher’s twine. Hold onto it a little while longer.
Scale the julienned peel (6% of the weight of your fruit) and place it in a saucepot. Add just enough water to cover the peels and add some salt (This is one of the few times I don’t have a precise measurement for you to use. You just need salty water). Bring the water to a simmer and cook the peels for 5min. The salt will remove any waxy coating or remaining dirt on the peel as well as open it’s cell structure to help it candy later on.
Strain the softened peels and rinse them thoroughly to remove any salt.
Scale the water and combine it with the fruit segments, juice, peels and the cheesecloth bag of membranes in a saucepot. Bring the mixture up to a gentle simmer (Too much heat or agitation can ruin the structure of the pectin in your fruit) for 5-10min. Any foam that might surface can be gently removed with a spoon.
Let the mixture cool for a few minutes and remove the cheesecloth bag of membranes. Place the bag in small mixing bowl and using a second mixing bowl, press down on the bag to extract as much of the juice in the bag as you can. Add that juice back to the simmered fruit.
Combine the sugar and commercial pectin and whisk it together thoroughly. Any clumps of pectin will gel into lumps when added to the fruit if it isn’t fully mixed into the sugar.
Add the sugar mixture to the fruit and whisk it in.
Heat the mixture gently, stirring often, to fully dissolve the sugar mixture. While the mixture is heating, put a sheet pan or plate in the freezer to use for a set test.
Bring the mix up to a boil, skimming off impurities as they form. The cooking time will vary depending on the fruit and batch size, but once the temperature reaches 221F/105C you can start to test it.
Take a small amount of the marmalade mix and place it on the frozen pan or plate. Let it cool for a minute or two in the fridge and test the texture. If it has the consistency of syrup, it isn’t ready, but once it begins to form a skin and wrinkle at the edges, you have yourself some proof positive that the jam will set.
Add your lemon juice and gently mix it into the marmalade. The acid in the lemon juice helps the pectin in the marmalade bond to itself and helps to give some balance to the sweetness of the recipe.
Pour the hot marmalade into the cleaned and dry jars, almost to the rim. Seal them with the lid immediately.
Place all of the filled jars into a stockpot lined with a tea towel to keep direct heat off of the jars. Fill the stockpot with water until it comes about halfway up the jars. Bring the water to a simmer and place a lid on the stockpot. Simmer the jars for about 10min, then remove them from the heat and let them cool.

- 1000 g grapefruit segments and juice 100%
- 60 g grapefruit zest 6%
- 300 g water 30%
- 900 g sugar 90%
- 40 g pectin 4%
- 30 g lemon juice 3%
- Peel the grapefruits, removing any excess pith from the peels. Reserve the peels.
- After removing the remaining rind from the grapefruit, supreme (segment) them, saving the segments in a mixing bowl.
- In a strainer over a second bowl, save all of the membranes and seeds.
- After all of the grapefruits have been segmented, strain the membranes and place them and any seeds in a cheesecloth bag tied closed with butcher's twine.
- Add the juice from the membranes to the grapefruit segments and weigh them. Use that weight to measure the remaining ingredients according to the percentages in the recipe.
- Weigh and julienne the grapefruit peel. Add the peels to a saucepot with just enough salted water to cover the peels. Bring the peels up to a simmer and cook for 5min.
- Strain the peels and rinse them thoroughly to remove any salt water.
- Combine the peels, segments, juice, cheesecloth bag of membranes and the scaled water to a saucepot. Bring the mixture to a gentle simmer and cook for 5-10min.
- Let the mixture cool for a few minutes and remove the cheesecloth bag. Place the bag in a mixing bowl and press it with a second bowl to extract any juice. Add this juice to the segment mixture.
- Thoroughly combine the sugar and pectin and add it to the segment mixture. Stir gently over medium-low heat to fully dissolve the sugar.
- Bring the mixture to a boil and cook until it reaches 221F/105C and gels in a set test.
- Add the lemon juice and gently mix it into the marmalade.
- Pour the marmalade into clean and sanitized jars and seal immediately.
Thank goodness a proper recipe with accurate measurements. Cups and ounces don’t do it for me and can be very inaccurate. Great stuff. I love this marmalade but like a bit of white pith in it to give a bit of bitterness. What about a bit of whisky as well?
Hey Malcolm,
I’m glad you appreciate the metric measurement as much as I do! And whiskey in the marmalade is always a great addition.
Cheers! Chef Scott
great recipe and great information , could you please give me recipe for Apricot Jam ? appreciate your help
Hi Hala,
Thanks so much, I’m glad you like the post! Apricot jam sounds like a great idea. I can’t say I have a recipe for that offhand, but I will make one for a post and share it with you!
Cheers – Chef Scott
Fantastic recipe Scott. I tried it out and it made a perfect marmalade. The interesting thing was that it set at 95 deg not 105. Maybe because I am on the Gauteng highveld at 1600m ASL the temperature does not get so high. I also added a bit of ginger which makes an interesting variation. That quantity does not need to be added to your recipe as it is to taste. Thank you.
Hi Malcom,
Thanks for trying out the recipe! You are absolutely right, the altitude will effect boiling time and temperature. I love the idea of ginger added to it, that sounds great!
Cheers – Chef Scott