Making jam: a basic introduction

Making jam (her approach and my personal touch).

It’s not at all complicated. Either you make jam using existing recipes and following them from A to Z and in this case you don’t need to read this text because I do not have personal recipes to share. But if you are looking for hints and a bit of general knowledge about making jam then continue reading.

I wish I could tell you all about it but I’m not a professional “confiturier”, in French someone who makes jam as a job with formal food school diploma. I dohave about 52 years of experience and so try my best to transfer some of my knowledge/experience to family members.

I was 8 year old and she was 60 years old with 35 years of solid food/kitchen experience. She was a chef in a sexist, misogynist society but she made her presence felt in the numerous hotel’s kitchens and restaurants she worked for as chef or kitchen supervisor. Is it not pure irony that women have been cooking for centuries and that most known famous chefs are… men???

Making jam was a delight, a reward for her. A peaceful time in her hectic work schedule. It was HER kitchen in HER house and nobody was admitted but me. She was my grandma and I was her kitchen helper!

She taught me everything from measuring sugar to pressing the lemons for juice and putting the seeds in a cotton cloth (for added pectin). I did every possible chore: peeling fruits, cutting it to fit the jar, grinding spices I had never seen or heard of, washing the Mason jars, putting labels etc. but tasting the results of our labour was always the ultimate reward.

At age 12, with a solid 4 years experience behind the t-shirt, I was even allowed to prepare the paraffin for toping the glass jars. Learning from her and experimenting with multiple fruits and ingredients was fun, adventurous and at the end of the day: good for my tummy.

Written recipes? No. Looking once in a while in a cook book? No. Every detail was in her head. I thought she knew everything relating to jam making. She had answers to all my questions. So much experience… and she shared it with me.

Using paraffin is passé but the rest remains so true. Let’s explore some of it.

Cooking in general and making jam should be fun, not a stressful experience. There are tons of recipes out there: be inspired by them, not intimidated…

One factor you can not escape : you will have failures and successes because making jam is not rocket science but nevertheless a long series of decision-making gestures into the world of alimentary chemistry: not enough of this or too much of that can really make or break the final result.

I do not make jam in order to freeze it, but you definitely can because it’s ridiculously easy: just follow the instruction on the box. No experience in jam freezing so no comment on my part.

I use only cane sugar (sometimes brown, maple syrup, honey ) but never artificial sweeteners, but you definitely can for whatever personal reasons. No experience with artificial sweeteners so no comment on my part.

I have no experience with using frozen/thawed fruits. I use only fresh fruits. Making jam using chia seeds is also more and more popular but I have no experience making jam with chia seeds.

Granny was an avid reader and soon found out that using paraffin was a thing of the past. To my knowledge she never got a miss using paraffin but it was such a waste of time. It was also tedious and quite frankly seemed like playing with fire because contamination is sometimes difficult to spot and the consequences can be physical (stomach wrenching) and even fatal…

So, she embraced the idea that water bathing, as a way of long-term jam conservation, was safe and easy. I do too. Once, I discovered in a remote black spot of our cold chamber a jam jar of…15 years of age. I Inspected closely, smelled the content and my instinct told me to eat it. There was no digestive problems of any kind. The only drawback? Color was darker and aroma was lost but once again totally edible.

Water bathing works well and is safe. Rules to apply to correct water bathing methods are easy to follow. I will conclude this text with some insights/thoughts about water bathing.

There are a ton of recipes for making jam. My general method is not so different then the average method an average jam maker uses but as we say in French and English too: the Devil is in the details… The line between having bad, average, good or outstanding results is sometimes thin.

Let’s begin!

This is by far the easiest way to make jam : you take some fruits, add sugar, cook the mix, heat glass jars in oven & lids in boiling water, putting hot cooked jam into jars, put the lid on, putting all jars upside down for 6 to 8 hours until you can not sense heat on the jars, then putting jars in the refrigerator/freezer/shelf and voila!

This approach has some merits: it’s easy to execute. You just have to strain the cooked fruit from the jar and use it. The cooked juice will often be quite watery but you could use it as topping for ice cream, cake, yogurt etc…

But there are also problemsresulting from using this technique: the success rate is far from being optimal because you can not keep the jam for a very long time even in a refrigerator or freezer. Spoilage and contamination could occur during process and storage or letting an opened jar sitting too long at room temperature. If electrical blackout happens for a long period: you’ll lose everything.

The strict rule to follow is this situation : in the absence of water bathing you MUST use sugar as a food preserver and you can not be cheap about it. Like salt is a way to preserve food, sugar plays the same role: to preserve your cooked jam. Use a 50-50 ratio as a mininum and with 60% sugar and 40% fruit you are in a winning situation.

My other hint is to make this type of jam in small containers like 250 ml or 500 ml jars (8 or 16 oz) , maximum. Forget about the 1 Lt container. First, It’s less dramatic to throw away a 250 ml jar than 1 Lt, right? Second, a 1 Lt jar takes time to empty and you could find yourself with fermented “wine” before you finished easting the jam…

BEFORE using such jam for consumption: look at it from the outside and inside of the jar in order to see signs of spoilage: change of color?, white/black spots? change of smell? In case of doubt give a portion to the cat first and look for reactions.

Just kidding. If mixture smells bad, is cloudy or not clear DO NOT TAKE ANY CHANCES AND PUT JAM IN GARBAGE BIN.

Not putting enough sugar in the absence of a water bathing process is the number one error done by would be confiturier (confiturière for female). The second error, also very common is over cooking the preparation. But this is not a security issue like making jam with not enough sugar in the mixture…

REMEMBER: fruit does not contain pathogens unless it has been watered with contaminated water (E. Coli, as an example) unlike meat which needs chemical agents to slow down (not stop) spoilage.

This is what I would like you to keep in mind when making jam : fruit does not need to be boiled… Fruit is fragile and slowly cooking them in a medium/low high heat setting is enough.

Beware of recipes that ask you to boil jam, even for a short period of time, like 20 minutes. For the natural pectin contained in fruits to set with the help of sugar and acid, the jam mixture must be near boiling point, about 80 C (176 F) but not (obligatory) superior and for no more than 5-10 minutes or else the fruit will begin to break apart and get mushy.

It’s the first time that I have mentioned a fixed temperature so now you know one of my secrets: yes, I use a cooking thermometer.

You don’t see yourself using such an instrument? It’s OK. So a trick is to look closely at the cooking jam mixture for tiny bubbles forming and signs of water evaporation as well. The more water evaporates from the cooking mixture, the less watery the final result will be… but evaporation takes time and should be done at a low/medium heat level, not boiling.

For those of you who are going to use the water bathing method, keep in mind that the already cooked jam mixture is going to “cook” another 20 minutes in near boiling water temperature so boiling the jam mixture in the cooking pot is unnecessary. Better less cooking time in the saucepan then more because of those extra 20 minutes of “cooking time” in the water bath.

Why is there no need to boil the jam mixture more than 5 minutes? I have tasted lots of home made jams in my life – not made by me - and 50% of the time, the fruits are hard, leathery aspect. Taste and flavour were not optimal either!

Over cooking changes taste and texture (consistency) of jam. Ultimately, you want to find in the final product the taste, shape and texture of (almost) fresh fruits as you tasted them before you put them in a jar, right? So, no hard boiling!

My last observation : why take a (big) chance and have to put the jam in the garbage bin? Study and practice using the water bathing method every time you cook jam. Think of it as: “safe sex with jam” Soon you will master it and your mind will be at peace knowing your jam is protected from possible contamination.

All fruits contain a minimal amount of natural pectin. This is an extreme simplification of it: pectin is a glue that binds fruit cells together. When heated and in the presence of sugar and acidic compounds, it will “hold” (act as a glue) together the cooked mix making the cooked jam less watery.

The rest is a question of personal taste. Do you enjoy a jam that holds itself naturally (being more or less fluid/watery) or do you prefer a jam that is more spreadable?

Most jam recipes will not require you to add additional pectin or thickening agents like guar gum, xanthan gum, agar and chia seeds. This is why the evaporation process is so important. Get the most water out of the cooking mixture. This step takes time and should be done at a low/medium temperature level.

Working with additional pectin and other thickening agents is a bit intimidating but fairly easy. Personally, I only work with low-sweetened powdered pectin and guar gum because I like jam that holds itself and not overly sweet. Pectin makes a jam more jelly-like and somehow compact. Guar gum makes jam runny and not compact.

Using thickening agents has its own challenges (measuring the right amount, incorporating the agent into heating jam because if added pectin incorporates easily into cooking jam, adding guar gum is another deal…). I believe using thickening agents in jam recipes should be for those who already have good experience in making regular jam and want to experiment and be more creative.

Whatever your personal preference is pertaining to liking very sweet or medium sweet jam, a reasonable amount of sugar must be present in the final result or spoilage will happen sooner or later. Using the water bathing method, you can go as low as about 40% sugar but not much lower. Once again follow recipe and do not put less sugar than indicated.

Some people work with liquid pectin, I don’t. Liquid pectin is expensive and its take more to attain thickening goal then powdered pectin but if recipe asks for it, respect directions.

Pacific Pectin, located in California, is a provider of bulk (and big quantity) pectin and other thickening agents. Staff knows their pectin and help can be provided by them when additional information is needed. No incentives for me to mention their name.

Have you chosen the fruit you want to use in your jam? Have you done some searching about the content of natural pectin present in the chosen candidate(s)? Internet is full of information (sometimes contradictory…) concerning fruit that contain lots, average of very little pectin.

Blueberries, honey berries, cranberries, black currants (among others) contain lots of natural pectin so the result of your jam should be a mixture that reasonably holds itself.

Raspberries, sweet cherries and physalis (ground cherries) contain little natural pectin and the resulting jam will be more watery.

Another fact about cooking fruits is oxidation. Simply put: oxidation is a chemical reaction that damages living organisms, including Humans. Usually, this natural phenomenon happens weeks or even months after jam is done. It’s cosmetic.

The top part of the jam will get darker than bottom part. Taste will not be modified. It happens with all fruits but to a more or less extent.

Apricots, peaches, pineapples, apples (not all varieties) and other fruits will get pretty dramatic dark color if ascorbic acid or lemon juice is not added in sufficient quantity to cooking jam mixture. Dosage depends on quantity of cooking jam mix. I use minimal ascorbic acid or lemon juice. Simply stated if you put too much ascorbic acid or lemon juice, no oxidation will follow but the final product will have a rather strong acid taste. Follow recipe recommendations.

I always put 70% of cooked jam solids (cooked fruits) into a jar and no more than 30% cooked fruit juice . The more cooked fruit you incorporate into jar, the more the jam will hold itself naturally because natural pectin is present in the fruit not in cooked jam liquid.

One step that’s wise to adopt : never add water to fruit when starting the jam process making. Simply put: why add water (even a little quantity) and get the jam even more watery?

Here a simple method : calculate the total amount of sugar needed and total amount of fruit needed as well. Let’s suppose 5 cups of sugar and 10 cups of fruits. Begin by putting 1 cup of sugar at bottom of saucepan, then add 2 cups of fruits. Repeat until all quantities have been put one on top of the other in saucepan. Put lid, rests for overnight or from 8 to 10 hours.

The next step is only recommended if you are processing about or more than 5 kg (11 pounds) of fruits or more in the same saucepan.

If you know the performances of your electric or gas range by heart, you can put minimal heat on for the entire time period. When I say minimal heat, I mean minimal heat.

The minimal heat generated will slowly liquify the fruit and sugar BEFORE you begin the cooking process. If you do not want to add minimal heat during such a long period of time, the water content of the fruit will nevertheless slowly make the sugar soaked with the water contained in the fruit BEFORE the cooking period begins but it will be less intense if heat is not activated.

If you are processing a small/medium quantity of fruits (less than 5 kg) DO NOT heat the mixture of fruits and sugar BEFORE cooking begins because the fruit will probably start to cook BEFORE you are ready to begin cooking because of the low heating process.

5 to 10% of the chosen fruit should be not ripe yet because unripe fruits contain lot of natural pectin which will be of great help in making jam. Personally, I crush small and medium unripe fruit and just throw them in the saucepan.

Fruit is expensive and a good sharp knife will remove that little portion of wasted flesh instead of throwing the entire fruit in the garbage bin…

As stated earlier, all fruits already contain lot of water. If you decide for whatever reason to wash the fruit before cooking then be sure to let them dry for some hours before using them.

Water bathing jam jars is easy and steps to follow are not that numerous. The process of water bathing must respect certain rules. Read about them in any serious jam making cookbook.

Boil water in a big enough saucepan, stop heating process and cover with lid. Glass jams jars should not be in direct contact with bottom of saucepan. Use metal basket with handles to put jars into saucepan or put a metal plate at bottom of saucepan.

You don’t want glass jars to collide one with another once water bathing process has started. Make sure there is not a big gap between jars. Start process, going to 80/85 C boiling temperature is enough. Process should be for a minimum of 20 minutes, more time is not necessary.

Mistakes associated with water bathing:

Screw-on lids are too tight and air can not escape jar. If air is still present, contamination will occur.

Quantity of jam is too high in jar and boiling jam will get out of the jar during process or make its way touching the lid and will not provide a sealing-proof process. Contamination will occur.

Water boiling temperature should be around 80 C (97 F) not 100 C (212 F).

Hearing a “pop” coming from the lid a few seconds/minutes after jars have been out of the water bath only indicates that metal lid is retracting because of temperature difference between the water bath and ambient air. It is not a sign that a jar has been properly sealed. You must wait until glass jar and jam are completely at room temperature (6-8 hours) before verifying that the lid is solidly adhering to the jar

I only use brand new lids and new jars from reputed makers every time I make jam. I do not reuse them because I sell most of the jars. You can reuse glass jars & lids but make close inspection before reusing them because some used lids could hide dents made when opening a former jar and will make the next sealing process flawed. Some used jars could hide microscopic cracks and near boiling water temperature could make them spill the jam in water bath. Be prepared for failure if using used lids and jars.

I wish I had some favourite, fast and bullet proof recipes to share but like my granny everything is in my mind. Simply put: I see the fruit, I see the possible seasoning (vanilla, anise, maple syrup, ginger etc…), I chose the technique, I execute, I taste, I put into jar, I water bath, I store.

I always wait a minimum of 30 days before eating a newly made jam for the flavour to develop. I try not to pass 2 years before opening/eating a jar of jam in order to have a peak of aroma and freshness taste.

The fruit/sugar ratio I most often use is: 1.25 cup of sugar for about 4 to 4.5 cups of fruit.

Most of the time the result is great, sometimes, outstanding but once in a while the execution fails (yes, even after 52 years) because I put too little (sugar, lemon juice) or too much of an ingredient (pectin, guar gum). It’s life: you win some you lose some…

Following established recipes is the safest way to make jam if you do not have a lot of experience. Properly sweetened cooked jam and properly water bathing are the keys to long-term conservation of jam.

The only super important point to respect is to be prudent when you eat any kind of homemade product like sausages, jam, pickled food etc.

Marc Lamarre

This is not a copyrighted text. You can copy, share, print as you wish.

A warm thanks to FarmGirl-Z6A for reviewing this text.


@Shabou - on your mention of making Jam with chia seeds…

That is the only option that works for me now days. And that has to be limited to weekend only, or every other weekend. A high carb (standard American diet) causes me GREAT health issues, serious gut issues, arthritis, high blood pressure, high cholesterol, overweight, sickness, pain, surgery, etc…

Here is my recipe for Chia Jam… for those who may have similar issues when eating lots of sugar/carbs.

This makes 1 pint, can be easily doubled, tripled, etc

Start with around 2.5 cups of fruit — once cooked down will fill a pint jar about right.

What fruit ? your choice, what ever you like, or have ripe at the time. I made Chia Jam with early McIntosh apples, peaches and blackberries this year and AWESOME ! Sometimes I make it with just blueberries, or any kind of berry mixed with a little pineapple (very good). Use your imagination.

Put that 2.5 cups of fruit in a sauce pan on the stove over med heat and heat until it starts to simmer. While simmering it, you can take your fruit masher (potato masher), or just a fork, and mash it to the consistency that you like (chunky or less chunky)… and let it simmer for 8 minutes… stirring occasionally, then take off the heat.

Add the juice of half a lemon.

Add 2 tablespoons of chia seeds

Add the sweetener of your choice and as little or as much as you want. No set rule here.
Most of the time I use 2 table spoons of Coconut Palm Sugar, and 2 table spoons of Maple syrup.
We use only Paleo Diet sweeteners. Honey is Ok too…
If you prefer Honey, consider that honey should not be added to the mix, until it cools considerably. Heating honey basically destroys all the good healthy stuff in honey. If you wait until the mix cools down to 90 degrees or less, then add honey, you will retain some of the good health properties of honey.

If you are not used to low sugar jams… you might want to start off with 6-8 table spoons of sweetener, and work your way down over time. But still 8 tablespoons of sugar for 2.5 cups of fruit is a LOT less sweetener than most jam recipes call for.

Note this is not a cooked, canned jam… it is a fresh Jam, can be frozen too.

4 table spoons works fine for us, we are very used to low carb/keto. You may want more.

Once you have all of that added to the pot and stirred up good, you are ready to pour into (I prefer wide mouth pint jars). If freezing in pint jars, you really need to use wide mouth, not regular. Regular mouth pint jars get narrower at the top, and will often break, when (what ever you have inside) is freezing and expanding up some… with wide mouth jars I have never had a problem like that.

If you keep the lid sealed, it will keep in the fridge for 2 weeks… (you will eat it all by then) :slight_smile:
You can freeze them and they keep well for months… I have kept for a year and still very good.

Note with this type jam, you will notice the fruit flavor much more, and will be less overwhelmed with sugar. I have several pints in the freezer now that I have made this year.

Good Health to all !!!



Thanks so much for taking the time out to write this up and post it @Shabou . I have made jam for years and still learned some great tips reading it! :slight_smile:

That’s a great looking recipe @TNHunter . I want to try that sometime. I’m not currently eating sugar and trying to keep my carbs under 50 - 75g daily.


I took my fruit (pear, apples, cherries), when each came in season, and pressure cooked (15psi) the fruits to a soft pulp and mashed them then cooked them down to a desired jam thickness. Nothing else added.


Check your math and edit the line:

“Water boiling temperature should be around 80 C (97 F) not 100 C (212 F).”


I did check my math and at 15 psi over atmosphere at 500 feet above see level the temperature of boiling water is 250F. As you add fruit the foiling point of water rises till you hit the eutectoid point and then it starts dropping. (adding salt to ice on sidewalk).

He was referencing the statement in the orirginal post. 80 C is more like 176 F instead of 97 F.


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i think i might be missing something in the discussion.

But I’m quite sure water boils at 100 Celsius. (212F)
actually by (historical) definition, water at 1 atmosphere (standard pressure ~ at sea level) water boils at 100 Celsius.

if you increase the pressure (like in a pressure cooker) the boiling point will be above 100 C
If you decrease the pressure (like when you climb a mountain)
the boiling point will go below 100C. That’s why mountaineers take a pressure cooker with them. to make sure even with the lower pressure, their food stil gets warm enough.

A good thread with good info I prefer to cook as little as possible as heat destroys desirable molecules like some vitamins and other valuable complex molecules. As mentioned with honey it’s the same with fruit. I like using ceramic saucepans as heat is retained better and consistent from top to bottom compared to a metal saucepan whose bottom is much hotter than the rim. As metal can dissipate heat quickly. Hard to find these days. I have a Corning ware saucepan.
I did not know about chia seeds. I have to look into that. I have used calcium gelling products but found shelf life to be poor. No sugar is needed for them either.

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Yes, 80C = 176F.

My approach to jam making is a little different. I mostly make citrus marmalade. I cook the citrus rinds until tender, add the sugar and industrial pectin and then boil 1 minute only. Minimizing cooking makes for fresher tasting jam. I don’t like jams that taste cooked. I don’t water process however. The full sugar jam I make doesn’t need it. And I don’t sterilize the jars, I used them just out of the dish washer. However to keep the great color in the jam I freeze the jars until used. There is no loss in color and the jam looks just as fresh after a year in the refrigerator.

I don’t like low/no sugar recipes. The no sugar pectin which I have tried IMHO makes a jam that is like jello. All this is for no personal gain as I can’t eat sugary stuff due to diabetes!

Hint: For extra flavor add an inch of vanilla bean to each pint jar.

Hint. I always add my powdered pectin to the sugar before adding the sugar to the fruit. This avoids any lumps.

Hint. Occasionally due to the varying chopped fruit fineness jam may jell too much and be thick. I can thin the jam with a little water to make any consistency. I store the jam in the refrigerator after opening, doesn’t last long anyway as it is delicious! If I could I’d eat a pint of marmalade a week.

My approximate recipe derived from experience with industrial pectin:
6 cups prepared fruit
4 pound bag of sugar
3 tablespoons industrial pectin.

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Yes, 80C = 176F

I hope that I didn’t mistype that on the edit sheet that I gave you @Shabou . So sorry if I did.

Actually, since NASA had more failures than successes in its early days, maybe making jam is very much like rocket science.


Here is a resource for making fruit jellies and jams without added pectin by boiling to the “jelly point.” National Center for Home Food Preservation | How Do I? Jam and Jelly
National Center for Home Food Preservation | How Do I? Jam and Jelly

People have adapted these for a combined jelly/jam method for making jams by separating the solids from the liquid portion and then cooking the liquid with added sweetener until the “jelly point,” then adding the solids back into the jelly–this method has worked wonderfully for us with strawberries and apricots so far. It keeps the solid portion “fresher.”

These are their recommended temperatures at different altitudes.

Sea Level 220° F
1,000 ft 218° F
2,000 ft 216° F
3,000 ft 214° F
4,000 ft 212° F
5,000 ft 211° F
6,000 ft 209° F
7,000 ft 207° F
8,000 ft 205° F

Additionally, make sure whatever you are canning is at pH of 4 or lower to prevent botulinum, which is thermally resistant to these temperatures, taking hold. If one is not relatively certain there is enough acid in the canned product (by testing like litmus paper or general knowledge), then a couple of teaspoons of lemon juice per pound of fruit will suit.


Hello all:

Sorry for answering so late but so much work to do here in the summer season… What I meant to write is: water boils at 100 C but you do not need to water bath at that temperature either in C or F because using raging boiling water is unnecessary. Very hot (near boiling) water (thus the 80 degrees C or equivalent in F) is sufficient.

Marc Lamarre

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I prefer to use citric acid powder instead of lemon juice. The USDA canning guidelines say to use bottled lemon juice, which tastes bad to me. Otherwise you aren’t certain the acidity of the lemon juice you are using.

Citric acid has a more neutral flavor and is consistent in acidity. When I’m using cultivars that may be more sugar and less acid than anticipated by recipes - or when I’m winging it, I like to add some citric acid for good measure.

I seldom or never use commercial pectin. I’m prejudiced against it because it can allow gelling with less actual fruit than I expect to be in jam or jelly. I don’t want jam with a beautiful texture and a hint of fruit flavor. I want fruit with enough sugar and acidity to gel and keep.

Black currant is great for jam, has tons of natural pectin, tastes better after cooking, and can be more than 50% fruit. Can make 2 ingredient jam: black currants, sugar - in that order.

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