Ingredients 
Whisk a tablespoon of powdered pectin (preferably the no-sugar-needed variety) into the pot of cooking jam. Test for thickness and add another tablespoon if needed.
Good to read: apple jelly bbc.
Why is my jam too runny? This a very common mishap, and can occur for a couple of reasons. It may because there is not enough pectin and acid in the mixture. Or it may be because the temperature of 104C was not reached when cooking.
Bring the syrupy “jam” to boil in a pot. Dissolve 1 to 2 teaspoons of cornstarch for every cup of syrup in a small amount of cold water to make a slurry. Reduce heat and drizzle the mixture into the jam pot, stirring constantly. Gently simmer for 30 seconds, remove from heat, bottle and cool.
See, the truth is that the pectin web doesn't really solidify until everything cools down. That means it's tricky to tell whether you've achieved the gel point while the action is still hot and heavy. Enter the spoon: Before you start your jam, set a plate with a few metal spoons in the freezer. Read about blueberry jam water bath canning recipe.
The lemon juice lowers the pH of the jam mixture, which also neutralizes those negative charges on the strands of pectin, so they can now assemble into a network that will “set” your jam. More reading: collard.
Generally speaking, if your jam doesn't firm up, you were short in pectin, sugar or acidity or didn't get a hard boil. No matter how much you stir, you won't get effective heat penetration in larger batches, so some pectin gets overcooked, while other pectin is not activated.
If it has you know your jelly or jam is ready. If it still hasn't set then add another 1/4 to 1/2 a package of no-sugar pectin and bring it to a boil for 1 minute again. Remove the jars from the heat and skim the foam off.
The temperatures required for setting point are: Jams and marmalades: between 104 degrees and 105.5 degrees. Jellies: between 104 degrees and 105 degrees.
Cook it again Cooking jam without pectin requires practice and patience. A runny batch will just happen occasionally. If, after waiting, you find the jam is still too loose for your liking, empty the jars back into a wide pot and cook again.
Cook until tender – any longer and the fruit will lose its shape. No sugar is added at this stage because a high sugar concentration can cause water to be removed through osmosis and result in hard, unappetising fruit.
Pop a plate in the freezer at the beginning of your cooking time. Once you think that your jam has reached its setting point or has thickened, spoon a bit of the jam on the cold plate and tilt it vertically so the jam runs. You are aiming for a slow descent, not a runny mess. If it runs slow, it's set!
The Key Ingredient to Basic Fruit JamThe fruit and sugar need plenty of time to cook and thicken. A long, slow boil drives the moisture out of the fruit, helping to preserve and thicken it at the same time. Further reading: raspberry jam using jello.
First, remember that freezer jam is often softer and needs 24-48 hours to properly set. If you've waited that time and you still don't like how thin your jam is, use a rubber scraper and place jam back in a medium sized saucepan over medium-high heat. Combine 1/4 cup granulated sugar and 2 tsp cornstarch. See more: raspberry jam without pectin recipe.
Do no stir jam once boiling, but use a wooden spoon to check it is not sticking on the base of the pan. Stirring lowers the temperature and delays setting point being reached. It is wasteful to remove scum too often. Do it at the beginning and at the end.
Jams, marmalades and preserves should be added to sterilised jars and sealed while still hot. Your glass storage jars must be without chips or cracks. Just before use, they need to be sterilised and dried, using clean hands. Read about cherry jam recipe mary berry.
To set, jam needs the right balance of acid and pectin. High-acid fruits include citrus, cherries, green apples, pineapple, raspberries and plums. If you're using low-acid fruits, such as rhubarb, apricots, peaches and strawberries, you need to add lemon juice. See more: cinnamon cordial.
If your recipe called for lemon juice and you forgot to put it in, your mixture will not be acid enough for safe canning. You have to open the jars and put the mixture into a sauce pan. (If you made the jam or jelly recently and you carefully remove the lids without damaging them, you can re-use the same lids.) More reading: lemon good for health.
Q: How long can I keep my homemade jams and jellies once I open them? A: Opened home-canned jams and jellies should be kept in the refrigerator at 40°F or lower. “Regular” – or pectin-added, full-sugar – cooked jams and jellies are best stored for 1 month in the refrigerator after opening. Read our post about plum jam low sugar.
Watch the way the jam drips.If the jam runs right off the spoon and looks thin and runny, it's not done yet. However, if it forms thick droplets that hang heavily off the bowl of the utensil, but don't immediately fall off, it is either nearing completion or is done.
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