Wholefood Cooking

Category: Preserving

Low Sugar Jam



I’m thinking jam. Tis the season with the berries and stone fruits harvesting.

We have become very accustomed to fruits available all the year round, but you will find they have nowhere near the same level of flavour. Fruits are fleeting, lasting only a few weeks, but there is a way to capture that moment — jam. But not jam as you might know it, but a spoonful of deliciousness that tastes like the fruit it is, with just enough sweetness to bring out it’s full flavour. A snapshot of the season in a jar. Now I am often asked can you make jam with something other than sugar, or less sugar and the answer is complex, and included below. So here it all is – as Wholefood Baking is currently out of print, I’ve put the recipe here for you. I promise you that once you know the hows, it’s very easy. But there are rules….

The only fruit to use is that which is ripe, preferably organic and in season. Fruits such as this are bursting with natural sweetness, colour with enormous complexity and luscious flavour. The jam (it’s a universal recipe) here relies less on sugar, and more so on technique to capture the true complexity and glory of fruit flavour — it is a snapshot of the fruit at its best and the season. Jams are very easy to make, and will store in the pantry for up to one year. On a cold winter’s day, when you take that batch of scones out of the oven, you will thank yourself for your stash of homemade jams and the colour and taste of summer will lift your spirits.

Technically, the object of preserving is to slow down the process of decay. Food spoils from the continued activity of natural enzymes in all fruits and vegetables and the continued work of microorganisms in the form of moulds, yeasts and bacteria present in the food and air.


Jam relies on sugar to saturate the natural moisture of the fruit and thus preserve it. I am often asked if something other than sugar can be used to make jam — the answer is complex. Many of the sugar-free jams you see are made with white grape juice concentrate, use pectin and have been processed in a boiling-water bath. Because there is not enough sucrose to saturate the fruit and preserve it (and this is true of many other non-sucrose based sweeteners, such as stevia, agave and brown rice syrup), the boiling-water bath is the preserving method. I prefer to use one of the semi-refined organic raw sugars (not rapadura, which is too low in sucrose and too strong in flavour)( I like to use the Billingtons Golden Castor Sugar)  in the smallest possible amount, this allows the glorious flavour of the fruit to shine through.  Most jam recipes call for equal quantities of sugar to fruit by weight. You need about 60–70 per cent sugar for good gelling to occur naturally (sugar, pectin, acidity). I find this way too much sugar and prefer a ratio of 20–40 per cent sugar to fruit, but this will vary with the fruit — tart fruit will require more, and sweet fruit will require less. Because the holy trinity of sugar, pectin and acid is disrupted, this will result in a softer ‘set’, which I happen to prefer.

Pectin is a carbohydrate that helps to ‘set’ jam. It is particularly concentrated in the skins and cores of fruit. The conversion of the pre-curser substances to pectin occurs naturally during ripening but can also be forced by long cooking, as in the traditional methods of making jam without added pectin. Fruits vary in how much pectin, or pectin pre-cursers, they contain. Pectin produces structure and a kind of stiffness in jam by forming a water-holding network within the crushed fruit. Before gelling starts, individual molecules of pectin are surrounded and isolated from each other by water molecules. If the surrounding solution is acidic enough, the pectin loses some of its attraction for these isolating water molecules. Sour fruit will normally provide enough acid to take care of this step. If the acid content of the fruit is low, lemon juice can be added to make the fruit mixture more acidic. Once the pectin has loosened its hold on the water molecules, something more attractive must pull the water away from the pectin — this is the role of sugar. With its water stripped away, pectin opens out into a structure that links readily with other pectin molecules to form a three- dimensional network — a gel.


Fruits with high natural pectin and acid content include:  blackberries + crab apples + cranberries + plums+ quinces+ sour apples

Fruits with low natural pectin and acid content include: apricots+ blueberries + figs+ grapes+ guava+ peaches+ pears+ prunes+ raspberries + rhubarb+ strawberries

Low-pectin fruits benefit from the addition of lemon, to boost the acidity and thus setting. Unripe fruit (sour) will also increase acidity. Jam is best made with a good percentage of fruit that is not overripe because as the fruit ripens, the pectin breaks down and you will not get a good set.


The right pot is critical to making low-sugar jam, I cannot stress this enough.  Mine is a traditional French copper preserving pan that is shallow and wide. It’s about 12 cm (41⁄2 inches) high, 36 cm (141⁄4 inches) across the base and 39 cm (151⁄2 inches) across the top, with a 10 litre (350 fl oz) capacity. The wide surface area encourages evaporation and reduction, thus cooking the jam quickly. It is extremely difficult to make jam in a deep pot with a small surface area — tall pans are a major cause of runny jam.

However, you can make smaller amounts in your average large domestic saucepan. You can use a simple stainless steel pan — just make sure it is not too deep. A wider and more shallow pan with less capacity (for example, a sauté pan with a 5 litre/ 175 fl oz capacity and a depth of 8 cm/31⁄4 inches) is better than a pot with a 10 litre/350 fl oz capacity, but a depth of 16–18 cm (61⁄4–7 inches), or even a frypan with a large shallow surface area. It will mean you can only make small amounts at a time — about 2 kg (4 lb 8 oz) of fruit, but your jam will be more successful. You can also use a 20–24 cm (8–91⁄2 inch) typical domestic saucepan, but keep the amount of fruit to 1 kg (2 lb 4 oz).

Never make jam in large quantities — another cause of runny jam — and never crowd your pan. How much fruit you use (the weight) will depend on the size of your pan — for mine, I use 4 kg (9 lb). A good guide is to only fill your pan two-thirds full of fruit.


Always use tempered jars that can withstand the temperatures involved in sterilising, jam-making and storage. Some jars manufactured for products such as coffee, peanut butter and mayonnaise are not tempered and do not have strong seals on the lids. Jars must not be cracked, chipped or damaged in any way, and lids must not be scratched or dented. Jars can be re-used, but lids are good for one use only.


Your jars, lids, ladles and funnels must all be sterilised. This is easy to do in an oven at 120°C (235°F/Gas 1⁄2) for 20 minutes. Jars and lids must be sterilised, dry and warm. Once sterilised, turn the oven off and leave in the warm oven until the jam is ready. Equipment can also be boiled for 12 minutes in a large saucepan of water, then dried in the oven at a low temperature.


Bottling technique is the other very important part of making low-sugar jams — the jam must be spooned with a sterilised ladle through a sterilised funnel into warm jars (as hot jam into cool or cold jars will cause the jars to break) as soon as it is ready. Make sure the sterilised jars are warm (from sterilising and then being kept warm in the oven) and sit them on a wooden surface or on towels (so they don’t crack when the hot jam is added). This process will ensure the jars seal properly and that the jam does not spoil.

After ladling the jam into the jars, make sure there is no spillage as this will hinder a seal being formed. Gently wipe any spillage, taking care not to touch the sterilised lip of the jar. Place the lids on, taking care to touch only the outside of the lids. Holding the jars with a damp cloth (for a good grip), turn the lids until firm.

Let the jars sit until fully cool — do not move them for 12 hours or you can disrupt the vacuum process. A concave dip in the middle of the lid indicates a vacuum seal. If there is no concave dip, store the jam in the fridge and use straight away.

Once opened and the seal is broken, the jam begins to deteriorate and must be kept in the fridge.


The beautiful photo at the top of this post is ©Cath Muscat and all copy is ©Jude Blereau and Murdoch Books, and taken from Wholefood Baking. Published by Murdoch Books, 2013.

Peach Shrub + Poole China


“What on earth is Jude talking about” ? I hear you ask… well a shrub is kinda like an old fashioned cordial, only it’s vinegar based (which preserves it). I love them, and last Christmas I started trying them out and feel pretty confident to tell you how I did it. It’s going to take about 2 weeks, so perfectly in time for Christmas. I just picked up those babies above the other day on my way home… seconds.

The Poole china…well, this year Christmas will be in my new home, with all the family coming. I’m setting the table (part of it will be a trestle table) and I thought to myself, I would love, love to use Mum’s glorious green Poole china. I warn you I may shed a tear as I write this, i’m a bit emotional at the moment… the stopping after a huge and massive year, and it doesn’t take much to get me crying. Mum is 96 and still lives at home, independently, still cooking but absolutely not as capable as she once was. She is at the pointy end of the stick in life, and wanting to move things out of the home to people. The Poole china was to go to me, and I asked mum the other day if I could use it for Christmas. Well, this week I packed it into boxes with mum watching and bought it home. “Check if there is anything else in the cupboard” she said, so i did, and there was – beautiful Kosta Boda glass bowls, stunning glass bowl… “take them too”. My mum has never had a lot, but what she had was beautiful – she has spectacular taste. And here was I packing them to leave her home forever, she was passing this onto me, preparing to know that this part of her life, and indeed her life was coming to it’s close. My mum has always been there for me, when i hated her, yelled at her, left her, she has loved and supported me no matter what. What value of a mother ? It’s everything. So that’s the Poole china. This Christmas, no matter where you mum is, give thanks to her for without our mums, who would we be?


So recipe below… it’s super easy and I hope you enjoy it. I haven’t given you a finished photo of the shrub because mine is still in the making, but if you look around the internet you will see them – THIS pic is gorgeous and will give you the idea.  What I also do, when the shrub is finished is use the discarded peach (all sweet and vinegared up) to make peach chutney. Now, if you are looking for more Christmas ideas (like Marshmallow, Gingerbread House and goodness knows what, you can find them HERE. OR, you can just go to the blog and hit Christmas and have a look through.

May your days be merry and bright as we lead into this most special time of the year…

x Judeimg_6148,

Preserving the Harvest



Preserving is one of the things I love to do most, chutney is by far the easiest and a perfect place to use ripe, bruised or seconds fruit and vegetables and any home pot will do – except copper. Whilst I love copper for jam making, chutney with it’s use of vinegar is too acidic.

In chutney, the preserving agent is sugar and vinegar.  I like to use Apple Cider Vinegar with Rapadura sugar as the sweetener as my general rule but could be tempted to another vinegar depending on the fruit (sherry, raspberry spring to mind). Sometimes I like the fruity tone and complexity that an apple juice concentrate provides, and given that chutney’s are used in small amounts, I’m okay with that use of fructose. BUT, and there is a but. Chutney made with a juice concentrate or Rapadura (a low sucrose content) will require a BOILING WATER BATH (we will talk more about that later) to ensure preservation. Made with brown sugar (even the beautiful semi refined Billingtons Muscovado’s) and thus with a higher sucrose content, they will be fine simply packed very, very hot into a clean, dry, sterile and warm jars.

But let’s talk actually making the chutney yes? Dead easy. I like my chutneys to have a bright fruity flavour but with depth and fullness of flavour. I rarely follow a recipe and would like to guide you along that same path. You will get a better result as every bit of fruit you use will be different – all cooking is in essence responding the the raw ingredients nature has grown for you. Fundamentally the fruit forms the base of the chutney (or vegetable), the liquid is that which comes from the fruit and the preserving agents sugar and vinegar. Sweetness and further depth of flavour is ensured with some dried fruit. This is then tempered with a bit of onion for flavour and depth (I’m a bit iffy on garlic) and most definitely ginger. Lots of ginger. Then nuanced with spices – I consider allspice an essential for chutney. This is a spice in it’s own right, and not similar to mixed spice. Then depending on what I’m making, I will choose the spices to suit. That’s it. oh, and chilli (but please be careful – I think people overdo chilli in a chutney and it overwhelms).


I’m going to give you a guide line to make chutney, but if you’d like an actual recipe, you can find Pear Chutney here. 

  • I start by choosing a pot that will fit the amount of fruit I have – I am looking for the fruit to be approximately 2/3 up the side of the pot. Preferably one that is not to wide as this allows too much evaporation. Wash your fruit and chop – a size to suit you, but ensure that any bruised or damaged bits are discarded. But the wetter the fruit (berries, stone fruit etcetera) the bigger the pieces can be.
  • Add a small amount of onion – I do like purple onion for fruits, I think it gives depth with sweetness.You can see in the picture above it’s not overwhelmed with onion. Then chop up a whole lot of fresh ginger – I like nice biggish bits as you can see.
  • Add 1/2 – 1 cup of dried fruit – I like a raisin, as I think it has a deeper and more complex flavour, especially the muscats. But depending on the fruit, others might give a better end result – for example dates with oranges. Nope, you don’t have to chop them up.
  • Add your spices. Definitely allspice – the berries, or the ground – I would start with 1/2 teaspoon for 1 kg of fruit and go from there. Cinnamon quills are brilliant, start with one. For this nectarine chutney I chose to use Garam Masala as I love it’s play of peppery and spicy complexity, and added extra ground coriander just because I think ground coriander is beautiful with stone fruits.
  • Then add a good amount of apple cider vinegar – enough to give the dish enough liquid to start, with equal amount of sugar – whichever you are using, or apple juice concentrate (you can see the amount of liquid I start with above).
  • Then cover it with a lid and cook over a gentle heat until the juices have sweat out from the fruit – not too long, approx 15 – 20 minutes. Then assess if it needs more liquid – you need enough just about cover the fruit and saturate their cells. Go carefully adding more vinegar, and add in increments – you can always add more, but hard to take away. As you add vinegar, add sweetness to match. Then assess if it needs more sweetness, balancing the acidity or vice versa. Leave the lid off and continue to cook at a gentle simmer – blip, blip – too much boil and you will evaporate that liquid. After about 20 minutes, taste it to see again where the acid/sweetness flavour and liquid ratio is at. Adjust as needed, and also taste for spices and add as desired.
  • How to know that it’s cooked? You are looking to see that the fruit is saturated – it looks markedly different from fruit that is not cooked, or not saturated enough with the preserving mediums of vinegar and sugar. When it’s at that stage, you can then reduce it down to the consistency that you are after. A small chutney batch of approx 1 kg will take about 40 – 60 minutes.
  • I check, taste and adjust frequently when making chutney – for amount of liquid, acid/sweetness balance and spice.

Now you have your chutney. If you have made it with a generic brown sugar (NOT recommended as it is highly refined – thus not good for you –  and won’t add depth of flavour) or the semi refined Billingtons Muscovado (I like the Light Muscovado) you can simply funnel the very hot chutney into clean, dry, sterile and warm jars (make sure they are on wood/towels or thick paper so they don’t crack) and lid them. Leave to sit for at least 8 hours -you should hear them audibly ‘pop’ as the lid is pulled down during the vacuum formation, show a visible concave centre and then store them. The heat will give you enough of a vacuum.  But, if you’ve used a fruit juice concentrate or rapadura, that won’t stop the decay process. They will be fine in the fridge for some weeks but not in the pantry. So, you have to use a boiling water bath.

The boiling water bath is the tool (rather than the ingredient) that you use to preserve the chutney.

This is one of the most interesting techniques – we know it here in Australia as the Vacola system. In essence, what we are doing when we bottle, is to use heat and an enclosed system to destroy micro-organisms that cause food to spoil and create a vacuum in which remaining bacteria cannot grow. Food is packed into a bottle, a seal (originally rubber) is placed around the rim, then a lid is placed, using a clamping system to keep it closed. The Vacola system uses rubber rings with clamps placed on, the French have the rubber seals on the lids with the clamp attached to the lid. As the closed jar goes into water and is heated to a specific temperature (or in this case, boiling) air is forced out through the rubber, bacteria (and such) are killed, and when removed a vacuum seal occurs as the jar cools. When it’s fully cooled the clamps are removed – it is the vacuum seal that keeps air and bacteria out. Newer systems (mostly used in Europe and the U.S, but used now extensively here in Australia) have the lid and rubber formed into one – using a sealing compound around the edges. This is the creamy “paint” that you see on lids and specifically the fine, more darkly coloured ring closer to the edge. Many of the U.S systems (Ball etc) separate that lid into two: a top and screw section. Glass (only tempered) jars can be re used (if in pristine condition), but lids and rings must be new for each bottling. A special note must be made here that preserving, and especially bottling and the hot or boiling water bath,  is all about understanding acidity. Clostridium botulinum (extremely toxic) grows in the absence of air (a vacuum), low acidity and a moist environment. Fruits are generally high in acidity, vegetables and especially meats, low acidity. Here with chutney’s you’ve got plenty of acidity, but the process I am recommending is only relevant here for your chutney.

In regards to the pot the Fowlers Vacola is a commercial example of a hot or boiling water bath (just in case you are confused about the terms hot /or boiling water bath. In a hot water bath– the water comes 2/3rd up the sides of the jar, and takes a much longer time for preservation.In a boiling water bath – water is below, around and above the jar, and preservation is achieved in a much shorter time). The Fowlers Vacola preserving pot/system is not absolutely necessary – you can use any big (large) pot, AS LONG AS IT IS DEEP ENOUGH FOR THE WATER TO COVER THE TOPS OF THE JARS AND HAVE SPACE TO BOIL FREELY. ALLOW APPROX 12 CM  ABOVE THE JAR TOPS FOR BRISK BOILING.  Basically, the Fowlers Vacola system is a large pot – for a hot water bath it has a well-positioned thermometer, and for a boiling water bath, it has enough room.

With a stockpot, a few precautions must be taken to protect the jars from cracking. A wire rack must be placed on the bottom of the pot to keep the jars from direct contact with the heat, and to ensure the movement of boiling water around the bottom of the jar. Some people wrap the jars in paper or cloth to prevent rattling, but I have never done this. The American system is different and brilliant – it has a basket that holds the jars and is so easy to use – it’s available on – line in Australia, coming as a kit (which is worth getting) and you can find it here. Once you get there, you will need to click onto Preserving Kits from the side index. I couldn’t get it to link straight up for you.

Now you are set with understanding the role of the boiling water bath, and your chutney is done, this is what you do next. Bring your pot of water nearly to the boil.

Remove the clean, dry jars and lids from the oven (they should be warm), keeping them on their trays, and ladle the hot chutney into the jars, using a funnel. Place the lids on the jars, then screw on. Make sure the water isn’t boiling as you lower the chutney into it. As a note:it’s important that you put warm chutney into warm jars, otherwise if the filled jar is too cold it will crack when it hits the nearly boiling water.

Using special tongs, lower the jars into the not far off boiling water (or if you have the American basket system, place in the basket). Boil for 12 minutes, starting that timing from when the water comes back to the boil. When done, using the same tongs, remove and place the jars on a towel or wooden surface. Let them sit until totally cool – at least 8 hours.

If you are using a screw top lid system, they should pop audibly as they cool – this is the sound of the lid being sucked down as the vacuum forms. If you are using a screw top lid system or the Vacola system there should be a concave dent in the middle of the lid (for Vacola this is visible when the clamps are taken off). If this has not occurred, store in the fridge and use soonish.

Preserving the Summer Bounty – Seminar

Everyday with Wholefood Seminar

Sunday 21 November 2010

1pm to 4.30pm

In our final seminar for 2010, ‘Everyday with Wholefoods’ takes a look at summer and all the beautiful fruits coming into season.  Jude’s focus will be on Preserving including Jams, Chutneys and Bottling. She’ll also talk of menu planning for summer and provide a menu plan and recipes to take home!

Our guest speaker will be Annie Kavanagh of Spencers Brook Farm, who specialise in rare breeds including Berkshire pigs, Long Horned Wiltshire sheep and Dexter cattle all farmed to the highest organic and free range standards.  They also offer a premium range of preservative and gluten free hams perfect for Christmas! Come and hear their story!

We also hope to bring you local organic orchardists with news on how to get the best fruit for preserving.

We’ll also have a great range of local producers and retailers on hand for pre and post seminar shopping!

Special door prize: Preserving Pack kindly donated by KitchenWarehouse along with a discount voucher for everyone!

Event Program

Local organic orchardistto be confirmed

Annie Kavanagh – Spencers Brook Farm

Organic animal farming, Christmas hams

Jude Blereau –Whole Food Cooking

Preserving and summer menu planning

Booking Details

Sunday 21 November 2010

Time: 1pm – 4.30pm (Doors open from 12.15pm)

Venue: FJ Clarke Lecture Theatre

P Block, QEII Medical Centre,

Nedlands. Access off Caladenia Ave, (via Monash Ave)

Price: $38.50 incl GST

(seating is unallocated, tiered theatre-style – door sales will be available – cash only)

Discount available for Thermomix consultants only – Consultant No. must be supplied with booking details

Books, local produce and other merchandise will be on display and sale from 12.15pm

Please leave time for parking. Parking is available at various carparks around the Medical Centre on Sundays. 


Summertime and We’re Jamming

Right now in Australia, it’s hot as hell and the fruit is fabulous. It’s time for preserving the harvest, and it’s one of the things I most love to do. Yes, it’s time consuming, but when it’s all done and the pantry is filled with strawberry and apricot jams, bottled peaches and nectarines, it’s a glorious sight. Seeing a pantry filled with preserved food makes me feel as if I can handle anything life may throw at me – I must have had a past life where I starved to death ! I feel prepared and able. It’s also a great way to help reduce your food costs by buying organic seconds direct from the farmer and stay in control of the amount of sweetener used. So, whilst there’s still a bit of summer to go, I thought we would do Low Sugar Jam – it is easy to do at home and you need little equipment. Just a word of warning – once you’ve bought the fruit and are committed, it will be the hottest day of the year. Please forgive me if I’m giving you a lengthy blog, but I wanted to do the whole jam thing with you.


Many people ask me if something other than sugar can be used to make jam – my answer is yes, but it is complex. Many of the sugar free jams you see are made with white grape juice concentrate, use pectin and have been processed in a boiling water bath. Because there is not enough sucrose to saturate the fruit and thus preserve it (and this is true of many other non sucrose based sweeteners – stevia, agave, rice syrup, etc) the boiling water bath is the preserving method. Once open and the seal is broken, the jam begins to deteriorate and must be kept in the fridge. So, yes you can do it, but I’m not a big fan. I prefer to use organic raw sugar (not a Rapadura or such, which is too low in sucrose) in the smallest possible amount. Most jam recipes call for equal quantities of sugar and fruit. I prefer to use 30 – 40% sugar to fruit (thus if I have 1 kg of fruit, I need 300 – 400 gm sugar). Because you need about 60 – 70% of sugar to fruit for good jelling to occur naturally (sugar, pectin, acidity), low sugar jams have a softer set – which I happen to prefer.

The Pot and Amount of Fruit Used:

A good pot is critical to making low – sugar jam. Mine is a traditional French copper preserving pan – shallow and wide. It’s about 12cm high, 36cm across the base and 39cm across the top, with a 10 litre capacity. The wide surface area encourages evaporation and reduction, thus cooking the jam quickly. It is extremely difficult to make jam in a deep pot with a small surface area. If you want to use a large stockpot, choose the one with the most shallow depth, and only place a small amount of fruit in the pot to cook – about 1/4 full. The recipe below is for 4 kg fruit, which fits my copper preserving pan. You may need to adjust the amount of fruit you use to fit your pot – remember, it’s a good guide to fill a stockpot just under half  full – it will reduce to about 1/4 full. 

Sterilise the Jars, Lids, Funnel and Ladle:

Jars must be tempered glass, and the lids must be intact – dents, rust and  scratches will hinder a vacuum seal forming –  new is best. Wash them, shake out the water and place on a oven tray lined with a clean tea towel. Do the same with the lids, funnel and ladle.  Place in 120c oven for 20 – 25 mins.

Making the Jam:

4 kg fruit (if using stone fruit, weighed with the stones still in)

1.2kg organic raw sugar – plus a bit extra if needed

1 medium size lemon, skin on, cut into approx 8 pieces


Wash the fruit

(no need to dry it) and cut into smaller portions. Discard any seed (as in apricots etc). As a general guide, leave blueberries and small strawberries whole, but chop larger strawberries, cut apricots and plums into halves or quarters, cut figs into quarters or smaller segments.

Put the fruit in your jam pot, together with the sugar and lemon. Gently stir the sugar through. 

Stage 1:

Place the pot over a very low heat, allowing the sugar to dissolve – this takes about 15 min, or a bit longer depending on the size of your pot.

Stage 2: 

Once the sugar is visibly starting to dissolve, increase the heat slightly until you see a gentle bubbling. Stir frequently. Continue to cook for 15 min or longer if the pot is deeper – the juices should have weeped out from the fruit, thus increasing the amount of liquid in the pot. 

Stage 3:

Increase the heat to a high boil and allow the sweetener to fully saturate the fruit. Before I turn the heat up to a crazy boil, I am looking to see that the cellular structure of the fruit has broken down (that is, it’s not looking raw). When I see this, I increase the  heat so a very high boil is achieved. Stir frequently to check the feel of the jam and to make sure it isn’t sticking to the bottom. Check taste at this point – it may need a little more sugar. Our measurement was for 30%, so you have some lee way. As the jam reduces it will thicken. You may need to reduce the heat to a slower boil at times, but keep stirring. This stage should take about 30 mins, but the deeper the pot, the longer it will take. 

Stage 4 – ready:

Set is generally considered to occur when the jam reaches 105*c, but this doesn’t hold for l0w – sugar jams, where the relationship between sugar, acid and pectin has been disrupted. You need to rely on other techniques to judge when your jam is ready. I go by appearance and feel, and cook the jam until it is fairly thick. The bubbles also, become more volcanic and flat. Placing a small amount of jam on a saucer or dish is another good method for checking the consistency – run your finger through the middle. You want to see a clear line of plate underneath. Any liquid should have body, and hold. 

The jam must be ladled into the warm jars immediately – this is very important, as this is what creates a vacuum seal and helps to preserve the jam. Make sure the jars are not on a cold surface – keeping them on the warm tray is a good idea. Fill the jars to within just over 1/2cm of the top rim – a smaller air space will create a faster and better vacuum – and remove (with a clean, damp cloth) any jam around the edge or lip of the jar. Those bits may interfere with a good seal. Place on the lid and tighten, remove to a cooling rack and leave until absolutely cool. You should hear the little “pop” of the lid sucking down and forming a vacuum as they seal. When cool, check for a concave dent in the lid – if there isn’t, store the jam in the fridge and use.