Jams, jellies, preserves, and marmalades can be prepared with little technology. This made them popular among women of old and slowly it is making a come back today.
Jams and Jellies have a high sugar content because Increasing the sugar content preserves food by resulting in a dehydrating environment for bacteria, yeasts, and molds. When spoilage occurs in jam and jelly, it is usually due to mold because mold can tolerate fairly dry environments. However, mold requires air to grow, so sealing the jars in a boiling water bath prevents mold growth.
Some molds can produce toxins at room temperature (jam jars stored in cupboards), and these toxins migrate throughout soft foods (jelly, jam). Long-term consumption of these mold products is linked to the incidence of some cancers (I think nearly everything is being linked to cancer these days). Therefore, it is recommended that soft, moldy food not be consumed. If you have a jar of jelly that has molded at room temperature, discard the entire jar.
Q. Is it necessary to process jams and preserves in a boiling water bath ?
A. Yes. This prevents growth of moulds and yeasts that could cause food spoilage and quality changes.
Sealing the jars in a boiling water bath produces a strong seal that should last at least one year. Sealing the jars by turning them upside down (as recommended by some pectin manufacturers) saves time on jelly-making day but results in a weaker seal that may fail during storage. Sealing the jars with paraffin wax is no longer recommended because too often the wax separates from the side of the jars, allowing air to touch the jelly and mould is possible. Mistakes melting the paraffin also caused many kitchen fires and severe arm burns.
Jam and Jelly Failures
When jellies turn out to be too thin or jams too thick, householders usually just find another use for them, such as ice-cream topping and cake fillings etc. However, understanding the causes of jelling defects may decrease their occurrence.
Pectin thickened jams and jellies are the most common and jel strength is determined by the amount of pectin present, the amount of sugar present, and the amount of acid present.
The fruit used contains some of each of these three jelling factors, but in unknown amounts depending on ripeness and growing conditions. This is why different batches will jel differently, and substituting the type of fruit in your favorite jam recipe may result in a different thickness.
Commercial powdered pectins usually have an acid (such as fumeric acid) added to help jelling in case the fruit is very ripe and contains less acid than normal. Pectin manufacturers formulate their packaged products to vary slightly from other brands, so it is best to use a recipe for a specific brand of pectin.
Most jam and jelly failures are due to householder error, or creativeness. The boiling time must be monitored accurately. Start timing with the full boil stage (bubbles all over the surface in the saucepan), and use an accurate timer (one survey found 20% of household timers were inaccurate). Substituting honey for white sugar usually results in a softer jel, however many people find they can substitute half this way and still have an acceptable jel. Jams and jellies contain a lot of sugar; they taste sweet. If you wish to prepare a lower sugar product, use a recipe specifically designed to require low sugar amounts. Simply decreasing the sugar in a standard recipe will result in a very weak jel.
If your jelly or jam is too soft to use as a spread, and you do not wish to simply use it another way, it can be re-made. This involves starting completely over. Re-made jellies may still have an inferior consistency, but there is usually improvement. Re-making jams and jellies is time consuming and requires more pectin, however for expensive recipes it may be a practical alternative. It is worth noting that remade jams and jellies will also result in less jam/jelly than you had the first time around.
TO REMAKE RUNNY JELLY OR JAM
There are several different procedures for this, the following is one if the original product was a cooked, powdered pectin recipe.
First re-make a trial batch of 1 cup then repeat the procedure using a maximum of 8 cups jelly.
For each cup of jelly or jam to be remade measure and set aside:
2 Tb sugar
1 Tb water
1 1/2 tsp powdered pectin
Combine the pectin and water, then bring to a boil, stirring constantly. Add the sugar and failed jam or jelly. Stir. Bring all to a full rolling boil quickly, stirring constantly. Boil mixture for 30 seconds. Remove from heat, skim foam,ladle into hot jars and process in a boiling water bath for at least 5 minutes, or the time specified in the original recipe.
Q. Why do crystals form in jelly?
A. Crystals throughout the jelly may be caused by too much sugar in the jelly mixture or by cooking the mixture too little, too slowly, or too long. Evaporation of liquid causes crystals that form at the top of jelly that has been opened and allowed to stand. Crystals in grape jelly may be tartrate crystals. (To prevent tartrate crystals in grape jelly, let juice stand in a cool place overnight, then strain through two thicknesses of damp cheesecloth to remove crystals.)
Q. What makes jelly syrupy?
A. Too little pectin, acid, or sugar. Excess sugar can also cause syrupy jelly.
Q. What causes weeping jelly?
A. Too much acid. Storage place was too warm or storage temperature fluctuated.
Q. What makes jelly too stiff?
A. Too much pectin (fruit was not ripe enough or too much pectin added); overcooking.
Q. What causes fermentation of jelly?
A. Too little sugar or improper sealing.
Q. Why does mould form on jelly or jam?
A. Because an imperfect seal has made it possible for mold and air to get into the container.
Q. What causes jelly or jam to darken at the top of the container?
A. Stored in too warm a place, or a faulty seal allows air to leak in.
Q. What causes jelly and jam to fade?
A. Too warm a storage place or too long storage. Red fruits (such as strawberries and raspberries) are especially likely to fade.
Q. What makes jelly cloudy?
A. One or more of these may cause cloudy jelly: Pouring jelly mixture into jars too slowly. Allowing jelly mixture to stand before it is poured. Juice was not properly strained and contained pulp. Jelly set too fast, usually the result of using too-green fruit.
Q. What makes jelly gummy?
Q. Can commercial canned or frozen fruit juice be used for making jelly?
A. It is best to use commercially canned or frozen fruit juice only in recipes with added pectin. Because fully ripe fruit is used, the amount of pectin in commercial juice may be too low to get a satisfactory jel without added pectin.
Q. Can a recipe for jam or jelly be doubled?
A. Never double a jelly or jam recipe. If a double batch of jelly or jam is cooked for the usual time, it will be undercooked -- which means the jelly or jam will be soft and runny. If boiled longer, it will have a caramelized flavor and dark color.
Hope the above info is of some help to all those new people out there about to make their first batch of jams and jellies.
The information has been taking from a variety of sources from the US home extension offices to a selection of my favourite jam and pickle making books.