Jam making

jam making

One could say that there are two kinds of cooking: the kind that involves instant gratification and the kind that requires some planning, patience and time. Most of us prefer the first kind, lacking both the time, the patience and the planning skills required for the second kind. Nevertheless, there are times when the achiever inside us turns us into a planner and we find ourselves buying two huge boxes of strawberries, getting out all the glass jars hidden in the cupboards, frantically looking for the correct lid to match the correct jar, always wondering how they ever got separated during the cleaning process, and the biggest pot in our kitchen to make jam. Or maybe that's just me...

Making jam is one of the most enjoyable and rewarding projects you can attempt in the kitchen. The difference between reasonably priced commercial jams and home made jams is so astounding, that once you try making them at home, you will never enjoy those too sweet preserves sold at the supermarket. They remind me of the sweets we ate when we were children, those where you guessed the flavour from the colour of the wrapping rather than from the actual flavour. Home made jams, however, all lined up on the kitchen counter, turned upside down look like the fruit they are made of. One can even try to spot the whole fruits which have remained nearly unblemished, floating in the sweet and sticky juice.

However corny and idealistic it may sound, making jam also a way to preserve every season in a jar and enjoy it months later, when one is yearning for a certain fruit or flavour. Actually, in my 48 hour-day dream world, I would make orange jam in January, rhubarb jam in February or March (it's my dream world, so rhubarb is not imported from the north of Europe and sold in one place in the whole city at 15 euros/kilo), strawberry in April, peach and cherry during the summer months, fig in late summer…you get the idea. In the real world, I am, at best, an irregular jam maker, so I have to take advantage of the few productive days I had some weeks ago when I was invaded by the planning guru and decided to try two different Strawberry jam recipes, which you can find in the recipe section of this page.

Having gone over the more "sentimental" side of jam making, it is now time to actually talk about technique, about things that can help you improve the jams you make at home in case you are already making them and to encourage those who have never tried.

Making jam is not difficult, especially if, when reading a recipe you understand the reason for each step of the process. I always think that in order to be able to cook instinctively and to change recipes to make them your own, you first have to understand the role each ingredient plays, the reason for each of the steps or techniques. Once you have really understood a recipe, you will know which steps to skip in case you have little time and which ingredients work in case you don't have those specified in the original text. That is why, apart from some notes on sterilizing which are always nice to have to understand the process, I have collected some information on the roles the different actors play in jam making, But first of all, a few points born out of personal experience:

1. The big batch vs small batch conundrum. One would expect jam making to be a large scale process which involves huge quantities of fruit and big pots, and it can be. It is true that if you are going to make the effort, you might as well make it once and have plenty of jam to go around as a result of it, but I actually find making small batches more enjoyable. First of all you don't need to plan ahead, you can just grab whatever fruit you have lying around and get going. There is also less clutter in the kitchen and if you are making small quantities you can even store them in the fridge without worrying about having to sterilize and process all the jars, which can be a bit tedious.

2. Recipes. You could go for new flavour combinations - like the ones I have included in the recipe section or, if you just can't be bothered, use a ratio that I have used plenty of times and which works well. 1:0.75 fruit:sugar + the juice of at least one big lemon. It's true that different fruits have different sweetness levels, so you can adjust this ratio, but in general it usually works. You just have to taste as you go along and adjust with lemon juice. 

3. The use of lemon juice. Whatever fruit you are using as the main flavour of your jam, freshly squeezed lemon juice is your ally. A trick I have learned to make jams taste brighter and less sweet is to keep some of the lemon juice back when you first mix the fruit and sugar and add it at the end. That way your jam will taste brighter and fresher.

4. Texture. The texture of your jam will depend on the fruit you are using. Some fruits have more pectin than others, so some recipes require you to add pectin to low-pectin fruit jams. It might be in the form of pectin powder or apple. In my case I don't mind a runny jam and I actually don't like jams which look like jelly, so I don't usually add any additional pectin.

5. Sterilising and processing. If you make jam at home you don't have to be as fastidious as you should be if you are selling it, so I try to simplify this process, which is what actually keeps most people from making jam. If the jars have to keep for a couple of months, I wash them and keep them under boiling water for 15 mins before filling them. Once filed (to the brim), I just turn them around so the heat of the jam can kill any remaining unwanted visitor and turn them the right side up after a while. If I am making a very small batch, I might even just store it in the fridge and not even bother about sterilizing. As with everything, this is common sense. if you open a jar and it looks mouldy, throw it away.

And now on to the actual lesson part of this post. These are some notes taken from two books I own which I recommend to anyone who wants to start preserving (the first one is a guide to preserving in general, not just jam making).


Sterilising & Canning

Before you go into making your favourite jams, chutneys and pickles you have to know the basics of making your preserved foods safe to eat for a long time. The need for canning and sterilising will always depend on when you plan to eat what you are making and where you are going to store it. If you plan to make a small batch of jam that will probably be used up in the following week there is no need to sterilise the jar you put it in and to process it later. Keeping it in the fridge will do the trick. If, however, you want to make jam to last a year you should take the necessary steps to ensure that it will not spoil over time. There are two basic approaches to processing jars and two different theories seem to arise: the North American and the European.

The European Theory:

Europeans tend to sterilise their jars before putting the jam inside by putting them in a pot of boiling water for at least 15 minutes. The jars will then be placed on a dry cloth until they are dry. Once the jam/preserve is made, it will be poured hot into the jar, right up to the brim. The jar will be closed straight away and placed upside down for one day. The jars will then keep for months in your pantry.

The North American Theory:

North Americans believe in the boiling water bath. They will not sterilise the jars before pouring the preserve inside them, as the boiling water bath will pasteurize the sealed jars along with their contents. Once the preserve is made it will be poured into the cleaned jars leaving a headspace which will be indicated in the récipe. This headspace is left in order to allow the contents of the jar to expand during the boiling water bath. The jars will then be closed, but not sealed tightly.

The boiling water bath itself consists in putting filled  jars in a pot of boiling water for a certain amount of time which will be given in the récipe. Some precautions to take into account are: place a rack, a cloth or even a piece of newspaper between the bottom of the pan and the jars, place the processed jars on a wooden board but not a Stone counter in case it cracks. Sometimes the récipe might even ask you to leave the jars in the pot until the water cools down a bit do avoid  the pressure difference caused by removing a jar from a water bath.



Most jams and pickles processed in a boiling water bath will keep for a year. Some delicate or low sugar jam are best if eaten within six months.  Marmalades and fruits in alcohol will keep for 2 years or longer. Opened jars should be kept in the fridge and consumed within a week (for fruits in syrup) to a few months (marmalade, relish and pickles). Putting preserves in small jars will help you finish them off before they spoil. If you observe any bubbling, fizzing, off smels, off colours or other signs of spoilage, throw the jar away.


Sweet Preserves

There are many kinds of sweet preserves: jams, jellies, marmalades, fruit cheeses and even fruit leathers.


Use ripe first quality fruit. Smaller fruit is often best because it has a lower water content and more concentrated flavour. Try to look for fruit with an acidic note. Ripe fruit should be processed as soon as possible. Once the fruit is combined with sugar, it will keep in the refrigerator for up to a week. If you are pressed for time, macerate the fruit in an airtight container in the fridge until you are able to cook it.

Sugar and Sweetness

Sugar is a preservative that reduces the risk of spoilage. It also develops flavour, adds succulence and contributes to a jam´s consistency. Granulated White sugar will be what most recipes call for, but some darker organic sugars can sometimes add depth and flavour. When substituting sugar with honey you will have to take into account that it has a higher water content and will therefore have to be cooked for a longer time, and the fact that it has a pronounced flavour. The sweetness of honey can vary from one variety to another but in general it is sweeter than sugar. You will therefore have to replace the sugar for a third to a half less honey by volume. Susan Geiskopf´s Putting It Up with Honey is a useful guide if you are interested in this.

Sweetness depends on taste and on the sweetness of the fruit you are starting off with. A good strategy is to start by adding less sugar and tasting, both the macerating mixture, as well as jam when it has been on a rolling boil. Add more sugar if needed at both these points taking into account that as the jam reduces it will get more concentrated and thus sweeter.


Many jam recipes rely on freshly squeezed lemon juice. Part of it is added at the beginning of the process, but a good idea is to add part of it at the last stage of the cooking process. This will give you more acidity and a fresher taste in your jam.


Pectin is a complex carbohydrate that occurs naturally in all fruits. Different fruits have different amounts of pectin – citrus and apples, for instance, are pectin-rich, whereas strawberries, blackberries and pears have less. In all cases pectin levels peak immediately before ripeness.

Pectin is a fascinating molecule and its properties make it indispensable to the preserver. Given the proper pH conditions and sugar concentration, pectin will form a three-dimensional matrix which traps water and disolved solids into a semi-solid mass we call a gel set.

For loose-set jams store bought pectin is not usually necessary. An alternative to using pectin is to use apple cores when making jellies and marmalades in order for them to set.


Many jam recipes start off by asking you to macerate the fruit, which means stirring together the fruit, sugar and lemon juice and setting the mixture aside for some time. Sugar jump-starts the transformation of raw frui tinto jam and, by drawing juices, it reduces the risk of scorching when the fruit-sugar mixture first goes into the preserving pan.


With a few exceptions jam should be cooked as quickly as possible. In the final minutes of cooking, as the hot jam becomes thick and sticky, moderate the heat to prevent scorching. A good thing to know is that if you can´t be near your pan of boiling jam, you can always turn the heat off, do whatever you have to do and come back to it afterwards. There is no harm in stopping a batch of jam midway through cooking, but there may be in leaving it unattended for a couple of minutes.

The gel set and “The Cold Saucer Test”

Jam goes through four stages in the preserving pan: raw, cooked, reduced and gel set. At the gel set the jam is thick, glossy and ready to be jarred. The traditional subjective test for a gel set is known as the “cold-saucer test”. Put a saucer with a couple of spoons into the freezer when you start to cook your jam. When you think the jam is done, take a bit of the mixture in one of those spoons and leave it on the saucer in the freezer for about 3-4 minutes. If the jam is done it shouldn't flow freely, it should form a light skin that wrinkles when you push your finger through it.



The Blue Chair Jam Cookbook,  Rachel Saunders

Saving the Season, Kevin West