Some people don't know the difference between jams and jellies. And many think that they are concentrated juices.
There is actually quite a difference and they are not made of juice.
Jam is a confection usually obtained by cooking different types of fruit in a pot. While not all types of fruit require it most are pitted and cut into pieces if necessary. An equivalent weight of sugar is then added to the mix. Jam is actually a very old method of food preservation used as a technique to conserve the most fragile fruits, though it was also used as a way to consume certain astringent fruits such as quince or bitter fruits.
Like sugar itself, jams were introduced late in Europe via the Arab world. In the Middle Ages, the name "jams" refers to all confectionery made from foods cooked in sugar or honey: sweets, candied fruit, etc. The jam was often called electuary, from the Latin eleucterium. Originally from Mesopotamian pharmacopoeia, it was used as a treatment. An electuary was the term given to medicine mixed with honey or other sweetener to ease oral consumption. It is probably a corruption of Ancient Greek ἐκλεικτόν (ekleiktón, “medicine that melts in the mouth, lozenge, jujube”), from ἐκλείχω (ekleíkhō, “to lick up”).
However, various recipes found their place on the dinner table at medieval banquets.
Long considered a luxury product, jams became commonplace at the beginning of the 19th century thanks to the discovery of beet sugar. Today, they are considered a pleasure food, with a relatively low nutritional value: they contain a lot of carbohydrates and a little fiber. On top of that most vitamins are eliminated during cooking process.
Jam and jellies are produced in much the same way, though certain steps are taken for jelly which is taken from the French gelée which is a more refined product.
In both instances fruit is put in a pot, jam bowl or concentration ball, and boiled with the equivalent of their weight in sugar or fructose sweetener until the mixture thickens. The jam is then poured, still boiling, into jars and sealed.
The jam basin is traditionally made of copper and a slightly flared shape to facilitate the evaporation of the water contained in the fruit. The copper basin provides better gelling because the pectin molecules form ion bonds with calcium ion (Ca2 ) to assemble. However, the copper releases Cu2 during cooking, the pectins will settle via these ions and ensure a better texture.
As the jam cools, it solidifies under the gelling action of the fruit pectin. It may be necessary to add more when using only pectin-poor fruits such as cherries, raspberries, pears or rhubarb. When using sweet fruits such as quince, kiwi, peach, or pear, it is also possible to add an acid (usually lemon juice) to prevent the formation of sugar crystals.
While a good jam is thick with pieces of fruit and slightly opaque the same cannot be said about a jelly which is characteristically clear and refined.
From there it is not hard to understand why some might think that the jelly is a product of thickened juice this is not the case. Marmalade on the other hand is produced from juice which is where some of the confusion my come into the equation.
Though I don't make as much jelly as I did some years ago there is one that I love to make because it is so easy. I make jelly from pears. This jelly is quite simple to make as the skin and seeds of this fruit are loaded with pectin so it quite easy to make. The most complicated part of the process I would say: it's cooking time but with experience it is a snap. I also love its beautiful amber color that it gets throughout the cooking process.
Hopefully that clears up some confusion and gives you a better understanding between the differences of our different breakfast toppings.