#121 When did people start making jam?

I learned this today. Fruits were being preserved as jams since at least before the ancient Greeks.

Since the paleolithic period, people have been preserving foods in different ways. Drying was the easiest way and probably the first form of preservation. Chilling would have been possible in cold climates, but not all year round. People have been producing salt since at least 6,000 BC and salting to preserve food started in about 3,200 BC. Pickling in vinegar started in around 2,400 BC.

People have been using honey since 6,000 BC and syrups of honey were used to preserve food. Some of the earliest candies were dates and figs preserved in syrups.

The Ancient Greeks used honey to preserve quince and they were the first people to put the jam in glass jars, (although clay pots would probably have been cheaper).

The first recipe for jam comes from the world’s first cookbook: De Re Coquinaria (The Art of Cooking). It was written by Marcus Gavius Apicius (or at least attributed to him) in Rome in about 70 AD.

Honey was the preserve of choice for the next 10 centuries. Sugar cane was domesticated by the Papuans in New Guinea, about 6,000 years ago. Sugar travelled from there to India where people worked out how to refine it. It went from there to China and on into the Middle East and the first jams with sugar were possibly made there.

Sugar was brought back to Europe during the crusades, in the 11^th century. The first mention of sugar in England was in 1099. It was called “sweet salt” and people thought it a spice. It was extremely expensive. A record from London in 1319 says that sugar was 2 shillings for a pound. That is about $50 in today’s money. That is not a good comparison though because many of us could easily afford $50. In the same year, an unskilled laborer would have earned 40 shillings a year. A master carpenter earned 107 shillings a year. 2 shillings was 24 pence. A gallon of wine cost 5 pence. A sheep cost 12 pence. The yearly rent for a cottage was 60 pence, 5 shillings. Sugar was not cheap.

The first preserves made of sugar were made for the rich and royalty. Louis XIV is said to have finished royal banquets with jams made from the fruits in his gardens. Marmalade was created in 1561 by the physician to Mary, Queen of Scots. It was supposed to help her with seasickness.

The price of sugar dropped in the 18^th century. Production increased, imports increased, the Industrial Revolution mechanized the refining process, and there was rising demand as people moved into the cities and changed their diets.

These things encouraged the increasing production of jam with sugar, but it didn’t take off until a method to bottle it was found. In France, in the early 19^th century, Nicolas Appert discovered that boiling food at high temperatures and then sealing it in an airtight container kept it safe. He has become known as the “father of canning”. Louis Pasteur built on these findings to develop pasteurization. These techniques were used in the production of jam.

The price of sugar dropped, and the quality of the jam improved. In 1874, sugar duties were repealed in the UK and by the late 19^th century, a lot of working class people in England were using jam to make their dark wholemeal bread taste better. In World War 1, both the UK and the USA included jam in their ration packs and when the soldiers came back, they wanted their jam. It was firmly in the culture.

So why does making jam preserve the fruit? The important ingredient is the sugar and it should be at a ratio of about 1:1 with the fruit. Too much sugar and the fruit will crystalize. Not enough sugar and the fruit will spoil. Sugar is hygroscopic, which means that it absorbs water. It draws water out of cells in the same way that salt does. Without the water, bacteria cannot reproduce and spoil the fruit. However, the sugar is not the only thing that preserves the fruit. When the fruit is boiled down, it becomes more acidic, and bacteria cannot grow in an acidic environment. Added to this, the airtight jar keeps the bacteria out and removes air, which the bacteria need to reproduce.

Why does jam become a gel? A gel is defined as a liquid that behaves like a solid. Yoghurt is also a gel. Jam becomes a gel because when it is heated the structure of the sugar changes and it bonds with the pectin in fruit. Pectin is a polysaccharide (a carbohydrate) that is found in the cell wall of plants and fruit. The sugar and pectin bond, making a stable structure. Also, the heating process reduces the amount of water in the fruit and causes the jam to thicken.

So, fruit has been preserved with sugar for thousands of years, but jam has only become mainstream over the last 150 years. And this is what I learned today.

Photo by Torsten Dettlaff from Pexels

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