I love shopping for preserves, and I love eating preserves. I love making preserves too, but here’s the thing: I cannot stand recipes that suggest that I cook my jam to the “desired consistency” or until it “passes the wrinkle plate test”. Say what? How do you know when marmalade is ready?
Let’s be honest. If you are not a jam and marmalade expert and if you don’t make preserves very often, you will probably lack the experience to see the visual cues of the perfect set. I know that I can’t always tell!
I hate guessing games and, as you know, I love to measure everything. And that is how the marmalade temperature experiment was born.
How do you know when marmalade is set?
You have three basic options for determining if your marmalade has cooked enough and will set properly after cooling:
- the bubbles: when the marmalade first comes to a boil, the bubbles are quite volatile, they form and pop almost instantaneously, whereas when the marmalade has thickened enough, the bubbles will be more stable and resemble blinking fish eyes. The visual cues are hard to see for beginners so if you are learning to make marmalade and jams, I recommend you observe the changes in the bubbles as you go, but you should rely on other methods to decide when your marmalade has reached the setting point.
- the wrinkle plate test: freeze a few small saucer plates in your freezer overnight. When you think your marmalade is cooked enough, retrieve a saucer from the freezer and place a dollop of hot marmalade on the plate. Put it back in the freezer for 1 minute, then take it out and push the dollop with your finger: if the dollop wrinkles nicely, your marmalade is probably done, if it’s still too fluid to wrinkle, keep cooking.
- the temperature: measure the temperature with a candy thermometer. You want to cook marmalade to somewhere in the range of 217ºF to 221ºF, depending on how fluid or thick you want it. Don’t overcook your marmalade because the peel will become chewy and the sugar will caramelize, so be careful how high you push the temperature before you stop cooking.
In general, once you achieve the right consistency according to your tests and then you have canned your marmalade in jars using a water bath method, you must set the sealed jars aside to cool and it will take 24 to 48 hours for the marmalade to thicken and achieve the final set.
I cooked up a batch of three fruit marmalade, using the whole fruit method (no pectin). It contained two oranges, one lemon, and a grapefruit to be exact. I measured the temperature as the marmalade bubbled away with a pink Thermapen (Amazon), and I took samples every degree, starting at 217°F and all the way up to 222°F. I chose this range because most of the recipes I perused recommended cooking to somewhere in that range.
As the marmalade boiled and I sampled away, I honestly thought my experiment was a flop.
I could not have been more mistaken.
Behold, the results!
What is the setting temperature for marmalade?
It turns out there is a significant difference between marmalade cooked to 217°F and marmalade cooked to 220°F. Generally, the setting point of marmalade is 222ºF (which comes out to about 105ºC). Cooked to 220ºF, marmalade will be very thick and will set properly once cooled. But some people don’t like to cook marmalade that much and prefer a looser set, others prefer to go a little higher, up to 222ºF. That’s entirely up to you. Here’s the impact of cooking temperature on marmalade set:
- marmalade cooked to the lower end of the range (217–218°F or 103ºC) has a bright citrus flavour like fresh citrus fruit, but it is more on the watery side of set. The peel is very tender. Marmalade cooked to this temperature dribbles off your toast and leaves a trail in your kitchen or on your keyboard, if you are like me, doing chores while eating marmalade on toast in the morning, without a plate to catch the drips. Delicious, but drippy.
- marmalade cooked to the middle of the range (219°F or 104ºC) is not as drippy, but not overly set. The flavour is still bright and the peel is tender, but the preserve is just a touch thicker.
- marmalade cooked to the upper end of the range (220–221°F or 105ºC) is set just right for me: 220°F is considered the setting point of jam, also known as the gelling point, and this is where things get really interesting. The marmalade is much thicker, but with a touch of dribble to it, the peel is firmer, and the flavour is completely different. The citrus flavour is still there, but it’s not as bright. The caramel undertone is coming through and there’s a bit of a bitter orange flavour that lingers.
- marmalade cooked to the setting point, 222°F (105.5ºC), is chewy and very thick: this is the upper limit, in my opinion, as beyond this point, the peel gets really, really chewy. At 222°F, the peel is a “nice” chewy. Past 222°F (106ºC), the peel is bordering on tough, and not so pleasant.
Do you need to add pectin when making marmalade?
Seville oranges have the most pectin, so a batch of Seville orange marmalade definitely does not require the addition of pectin. But that being said, citrus fruit vary as does their pectin content. As we can see above with my temperature experiment, the marmalade set has a lot to do with the concentration of sugar and the removal of water, and not as much to do with the pectin content. If we compare a dollop of pectin-set orange marmalade from the store to homemade marmalade with no extra pectin added, you will notice the pectin-set marmalade is more jellied, seemingly dryer. The store-bought marmalade with pectin definitely doesn’t have my favourite texture. It smears funnily on toast, and I found the jiggle of the pectin-set marmalade unpleasant, and a little odd.
It’s honestly a matter of personal preference, but now I hope that you can better understand your options and pick your favourite. I don’t think there’s a right or a wrong. Well… there’s definitely no wrong when it comes to marmalade. I love them all. My favourite was definitely above 219°F. Probably 220–221°F. I love the flavour of the marmalade in this range, and I am happy that it will stay put on my toast. Then again, I cooked a batch of marmalade to 222°F and I love how it’s a little darker, with a deeper flavour. In a perfect world, I would have a jar from each temperature on hand, at all times, to suit my mood.
Which marmalade do you think you would prefer?
Marmalade not setting?
After your batch of marmalade is canned and left for 2 days to cool and achieve its final set, if you open your first jar and find that the marmalade is runny, it means that you didn’t cook the marmalade for long enough or to a high enough temperature. Your batch of marmalade contains too much water still. You have two choices if your marmalade is not setting properly: either you live with it OR you open up all the jars of marmalade, combine them in a pot on the stove, and cook it again up to 220ºF. You will have to go through the process of sterilizing the jars again and canning the marmalade in the sterilized jars in a water bath.
As I mentioned, you can save and fix a marmalade that doesn’t set properly because it’s undercooked by reheating the preserve, bringing it back up to a boil and cooking to 220ºF–222ºF before transferring to sterilized jars and sealing. On the other hand, if you’ve overcooked a batch of marmalade, there’s not much you can do. Overcooked marmalade has a few characteristics: chewy, tough citrus peel, possibly rubbery and a thick texture verging on dry. I have been guilty of overcooking marmalade when I was trying to determine the set with a plate test: I left the pot of marmalade on the stove, which continued to boil while I was fiddling with the plate test. In those few minutes, the temperature of the marmalade continued to rise, and I ended up with a rubbery marmalade. Unfortunately, there’s nothing you can do to salvage a batch of overcooked marmalade. Of course, you can still eat overcooked marmalade and learn from this mistake. Remember to pull the pan off the heat while you determine if you’ve achieved the proper set and use an instant-read probe thermometer (like this Taylor probe thermometer on Amazon) to make sure you are able to measure changes in temperature as they happen with little delay!
The recipe for this homemade three fruit marmalade is now available.
Janice Lawandi is chemist-turned-baker, working as a recipe developer in Montreal, Quebec, Canada. She studied pastry at Le Cordon Bleu in Ottawa and cooking at l’Académie Culinaire. She has a BSc in Biochemistry from Concordia University and a PhD in Chemistry from McGill University.