Blackcurrants are rich in natural pectin, so this jam sets with nothing but fruit, water and sugar. The one thing that makes or breaks it is patience at the start: the berries simmer in water until their skins are tender, and only then does the sugar go in.
- Makes
- varies with how far the jam boils down; have more jars sterilised than you think you'll need
- Keeps
- around a year unopened in a cool, dark, dry cupboard; once opened, in the fridge for a few weeks to a month or two
- Ready to eat
- once cool and set
- In season
- from midsummer onwards, depending on the variety
Ingredients
- 1 kg blackcurrants, fresh and just ripe
- 940 ml water
- 1.25 kg granulated sugar
For a bigger or smaller batch, keep the same proportions by weight and volume (see the table below); never reduce the sugar.
Method
- Sterilise the jars: a hot dishwasher cycle, water above 90°C for 10 minutes, or the oven at 160°C (gas mark 3) for 10 minutes. Check the jar maker's instructions; some (Kilner, for example) advise against the oven for their jars. Let the jars dry fully, and time it so they are still warm when the jam is ready. Prepare new lids as the lid maker's instructions say (see the sterilising guide).
- Put a small plate in the fridge for the wrinkle test.
- Pull the stalks off the blackcurrants and rinse the fruit.
- Put the fruit and water in a large pan and bring to a simmer.
- Simmer gently for up to about 45 minutes, until the skins are tender and a berry squashes easily.
- Add the sugar and stir until it has completely dissolved.
- Turn up the heat and boil rapidly, stirring often as it thickens so it doesn't stick.
- After about 10 minutes of rapid boiling, start testing for a set: about 104.5°C on a thermometer, or a wrinkle on the cold plate. Take the pan off the heat while you do the plate test so it doesn't overcook (see the setting point guide).
- When it has set, take the pan off the heat and remove the scum.
- Leave the jam in the pan for a few minutes, then stir it so the fruit doesn't rise in the jars.
- Fill the warm, dry, sterilised jars while the jam is still hot, leaving about 5 mm of space at the top.
- Wipe the rims and put the new lids on straight away, so a vacuum seal forms as the jam cools.
- Once cold, press the middle of each lid. If it springs back up, that jar hasn't sealed: keep it in the fridge and eat it first, as you would an opened jar.
- Label and date the sealed jars.
Why blackcurrants need so much water
Blackcurrants are one of the firmer fruits, and they need far more water than soft fruit such as raspberries, which need barely a splash. That is why this recipe uses so much: 940 ml to 1 kg of fruit gives the berries enough liquid to simmer for up to three quarters of an hour without burning.
Once the sugar is in, the job changes. The aim is now a short, fast boil to setting point, not more softening.
Why it needs no added pectin
Ripeness is the catch. Fresh, just-ripe fruit sets best and over-ripe fruit may not set well, so cook it soon after picking. Picked at the right stage, blackcurrants are a high-setting fruit, in the same group as cooking apples, redcurrants, damsons and gooseberries. There is more on why some fruits set easily and others need help in the pectin guide.
Batch sizes
Keep the three ingredients in the same proportion whatever the size of the batch.
| Blackcurrants | Water | Granulated sugar | Notes |
|---|---|---|---|
| 500 g | 470 ml | 625 g | Half batch |
| 1 kg | 940 ml | 1.25 kg | The recipe above |
| about 1.8 kg | about 1.7 litres | about 2.25 kg | The original imperial batch (4 lb fruit, 3 pints water, 5 lb sugar) |
Getting the set right
Start testing after about 10 minutes of rapid boiling. A thermometer is the most dependable test, so use it if you have one and treat the plate as a check.
| Test | How to do it | Set when |
|---|---|---|
| Temperature | Thermometer in the boiling jam | It reaches about 104.5°C |
| Wrinkle | A little jam on a fridge-cold plate, left for a minute, then pushed with a finger | The surface wrinkles |
| Flake | Lift jam on a wooden spoon and let it drip off | The drops run together and break away in flakes |
Getting the timing right matters both ways. Boiling too long darkens the colour, spoils the flavour and can even give a runny jam. Boiling too little can let the jam ferment in store. Leave the scum until boiling is finished, then remove it in one go; constant skimming wastes jam.
The 104.5°C figure applies at sea level. Setting point is about 4.5°C above the temperature at which water boils, so it drops with height:
| Height above sea level | Setting point |
|---|---|
| Sea level | about 104.5°C |
| about 300 m | about 103.5°C |
| about 600 m | about 102.5°C |
Simpler still: check what your thermometer reads in boiling water and add 4.5°C. There is more on each test in the setting point guide.
Filling and sealing the jars
This is a hot-fill jam, so the seal comes from a new lid put on while the jam is hot. Use a proper lid rather than a waxed disc and cellophane cover. Never reuse old lids, and throw out any cracked or chipped jars. A few minutes' rest in the pan and a stir before filling keeps the berries spread through the jar instead of floating to the top. For choosing jars and lids that suit jam, see the jars guide.
Picking blackcurrants for jam
Blackcurrants ripen from midsummer onwards. With modern varieties the whole bunch (the strig) ripens at once: cut it off when the currants have turned black and strip the berries off the stalks at home. Older varieties ripen unevenly, so pick the ripe currants one at a time.
The "Ben" in the Ben varieties' names comes from Scottish mountains. They come from a breeding programme begun in Scotland in the 1950s to provide varieties suitable for northern parts of the UK, and now run by the James Hutton Institute. Ben Connan, Ben Hope and Big Ben hold the RHS Award of Garden Merit (AGM). You can compare them in the blackcurrant varieties article; planting and pruning are in the blackcurrant growing guide.
A good bush can give far more fruit than one batch of jam uses. The blackcurrant and redcurrant glut guide has other ideas, and blackcurrant cordial is another way to use a big crop.
Storing blackcurrant jam
Keep sealed jars away from the light in a cool, dark, dry cupboard, where full-sugar jam keeps for around a year. Once a jar is open, keep it in the fridge and use it within a few weeks to a month or two. Throw out any jam with mould on it or a fermented, yeasty or alcohol smell. The preserve storage guide has more detail.
Common questions
Can I use less sugar?
No. Sugar is the preservative in jam. It stops microorganisms growing and helps it set. Jam with less sugar lacks that preservative effect and goes off sooner, and cutting the sugar can leave you with syrup rather than jam.
Why are the skins in my blackcurrant jam tough?
Most likely the sugar went in before the skins were tender. For the next batch, give the first simmer its full time, up to about three quarters of an hour, and check that a berry squashes easily before adding the sugar.
Can I scrape mould off the top and eat the rest?
No. Moulds on jam can produce toxins, so throw out the whole jar.
Do I need a water bath?
No. Hot jam in sterilised jars with new lids put on at once seals as the jars cool. If you follow a US tested recipe that includes a water bath, though, keep the bath.
Sources
Show the 17 sources
- Recipe proportions based on: Jam and Jelly Making, Dig for Victory Leaflet No. 10 (Ministry of Agriculture and Fisheries, 1941): Blackcurrant quantities (4 lb fruit, 3 pints water, 5 lb sugar) and method (stalks off, simmer 45 minutes, dissolve sugar, boil rapidly); high-setting fruits list; simmering to soften skins, up to ¾ hour for firm fruit; water to prevent burning (barely any for raspberries, much more for blackcurrants); fresh, just-ripe fruit; begin testing after about 10 minutes; over- and under-boiling effects; wrinkle and flake tests; skim only at the end; leave a few minutes then stir before filling; clean, dry, warm jars filled just short of the brim; label, date, store away from light in a dry, airy place.
- Jellied Product Ingredients (National Center for Home Food Preservation): Currants in Group I (set with sugar alone if not over-ripe); sugar as preservative; never cut sugar unless syrup is wanted.
- Basics of Jelly Making (Clemson Cooperative Extension HGIC): Currants in Group I; sugar preserves and aids gelling.
- Testing Jelly Without Added Pectin (National Center for Home Food Preservation): Temperature test is the most dependable; setting temperature of 220°F (about 104.5°C), 8°F (about 4.5°C) above the boiling point of water; subtract 2°F per 1,000 ft (about 1°C per 300 m) of elevation.
- Making Jam without added Pectin (National Center for Home Food Preservation): Take the jam off the heat for the cold-plate test; skim foam; ¼-inch (about 5 mm) headspace.
- Berry Jams without Pectin (National Center for Home Food Preservation): Stir frequently as the jam thickens to prevent sticking.
- Rowan Jelly: How to Find it and Make it (Woodland Trust): Wrinkle test on a fridge-cold plate, left for a minute.
- Food Safety and Labelling Guidance for small scale home producers (Scottish Borders Council): Three sterilising methods (oven 160°C/gas 3 for 10 minutes, hot dishwasher cycle, water above 90°C for 10 minutes); jars fully dry; discard cracked or chipped jars; don't reuse lids; lids on immediately while hot for a vacuum seal; jam sets around 105°C.
- Making Jam and Similar Products (Orkney Islands Council): Same three sterilising methods; don't reuse lids; jam sets around 105°C.
- Sterilising Jam Jars & Hygiene (Kilner): Advises against oven-sterilising its jars.
- Storing Home-Canned Jams and Jellies (National Center for Home Food Preservation): Cool, dark, dry storage; fridge after opening; reduced-sugar products deteriorate sooner; discard for mould, yeast, fermented or alcohol smell.
- Bust a glut: how to harvest and store your veg (Garden Organic): Jam lasts about a year in a cool, dry cupboard; refrigerate once opened.
- Blackcurrants: grow your own (RHS): Ripening from midsummer depending on variety; modern varieties ripen a whole strig at once, older ones unevenly; Ben Connan, Ben Hope and Big Ben hold the AGM.
- Blackcurrant Breeding (James Hutton Institute): Programme at the institute (formerly SCRI) established in the 1950s to provide varieties suitable for northern parts of the UK.
- Blackcurrants and Redcurrants Licensing (James Hutton Institute): The "Ben" prefix refers to Scottish mountains.
- General Information on Canning Jams, Jellies, and Marmalades (National Center for Home Food Preservation): US tested jam recipes include a boiling-water bath as part of the method; mycotoxins have been found in mouldy jelly.
- Currants, FNH-00115 (University of Alaska Fairbanks Cooperative Extension Service): Seal check once cool (press the middle of the lid; if it springs up, the jar is unsealed).