Here’s a handy tip sheet for troubleshooting problems when making homemade jelly…if a batch doesn’t turn out the way you hoped, you may find the reason why here so you can avoid the problem next time.
I’ve also added several vintage tips at the bottom of the page, lots here, enjoy!
- Why does it get cloudy? One or more of the following may be the cause: Pouring mixture into glasses too slowly. Allowing it to stand before it is poured. Juice was not properly strained and so contained pulp. It set too fast–usually the result of using too-green fruit.
- Why do crystals form? Crystals throughout may be caused by too much sugar in the mixture, or cooking the mixture too little, too slowly, or too long. Crystals that form at the top of the jar that has been opened and allowed to stand are caused by evaporation of liquid. Crystals in grape varieties may be tartrate crystals.
- What causes it to be too soft? One or more of the following may be the cause: Too much juice in the mixture. Too little sugar. Mixture not acid enough. Preparing too big a batch at one time.
- Why is it syrupy? Too little pectin, acid, or sugar. A great excess of sugar can also cause a syrupy result.
- What causes a weeping result? Too much acid. Storage place was too warm or storage temperature fluctuated.
- How come it’s too stiff? Too much pectin (fruit was not ripe enough or too much added pectin was used). Overcooking.
- Why is it tough? Mixture had to be cooked too long to reach jellying stage, a result of too little sugar.
- Why is it gummy? Overcooking.
- What causes fermentation? Too little sugar or improper sealing.
- Why does mold form? Because an imperfect seal has made it possible for mold and air to get into the container.
- What causes it to darken at the top of the container? Storage in too warm a place. Or a faulty seal that allows air to leak in.
- What causes fading? Too warm a storage place or too long storage. Red fruits such as strawberries and raspberries are especially likely to fade.
Source: How to Make Preserves at Home, U.S. Department of Agriculture
Most of these tips come from a vintage booklet published in the 1940’s giving advice to homemakers on a variety of topics, others I’ve snipped from vintage articles. The Timeless Wisdom collection is an occasional feature on Tipnut where we take a look back at the techniques and advice given to homemakers decades ago–many are still quite useful for today!
- A vegetable brush is just the thing to remove scum from the surface. Try it.
- If it turns to sugar it can still be salvaged as a delicious syrup for waffles or pancakes by adding 1/2 glass of water to 1 glass of jelly and heating just enough to dissolve.
- If hard or sugary, leave it in a warm oven until the sugar softens and it will be like new.
- To Harden: After glasses have been filled and allowed to cool and still it has not hardened, place the glasses in a pan of cold water and set in the oven, allow them to cook until stiff.
- Strong, dark colored product results from the long cooking.
- Product made from frozen berries are superior to those made from fresh fruit. The freezing and thawing break down the cells of the fruit and allow the natural colors to dissolve in the juice.
- It can be made much clearer and more attractive looking by straining the fruit and juice through a flour sifter. It saves a lot of time and effort too.
- For the clearest of jellies, do not squeeze the bag when extracting the juice. The juice yield will be less, but very clear.
- It is improved if in place of water, it is made with juice left over from either dried or fresh fruit.
- To economize on sugar when making jam, let the fruit boil for about 10 minutes before adding sugar. Only about 1/2 of the usual amount of sugar will be needed.
- If you put a teaspoon of butter in cold juice before you boil jelly you will not have a scum on it.
- To prevent jam/marmalade from burning: Rub the bottom of preserving pan with a little oil or butter. This prevents burning and keeps the product clear.
- Too much sugar is the most frequent cause of failure.
- Juice which does not have a tart taste is not acid enough and needs lemon juice added to it, about 1 tablespoon per cup of juice.
- Use equal parts of ripe and slightly under-ripe fruit for best flavor.
- Use hard-ripe fruits when not adding pectin; use fully ripe fruits if using pectin. Apples, currants, crab apples, grapes and sour plums do not need added pectin.
- For freshness of flavor: Prepare only the quantity that can be used within a few months; they lose flavor in storage.
- Hang a piece of string over the edges of the glass before pouring in paraffin. It will be easier to remove paraffin when opened for table use. *Paraffin method is no longer advised today due to food safety issues.
- Jellies can easily be sealed in the glasses by putting small pieces of paraffin in the bottom of the glass and pouring the hot jelly over it. The paraffin melts, rises to the surface and seals the glass perfectly. *This method is no longer recommended for food safety reasons.
Testing: Boil rapidly until the jelly stage is reached. To test, dip a spoon into the boiling mixture and let it run off the side as in the illustration.
When it separates into two distinct drops which run together and then “sheet” off the edge of the spoon, it is finished and should be taken off the flame. Then skim.
A thermometer may also be used. It’s done when the thermometer reaches 220 degrees Fahrenheit.
To Test Juice for Pectin:
Test One: Add 1 teaspoon of the cooked juice to 1 teaspoon of alcohol and stir slowly. If the juice contains sufficient pectin, a semi-solid mass will form. Do not taste.
Test Two: Add 2 teaspoons sugar and 1 tablespoon Epsom salts to 2 tablespoons cooked fruit juice; let stand 20 minutes. If a semi-solid mass forms, the juice contains sufficient pectin to make good jelly.
Bonus: You’ll find over 100 recipes here  featuring a variety of fruits, peppers and edible flowers.