- Testing for a Set in Making Jam and Jellies - Susan Morris
Testing for a set is an important part of the process of making jams and jellies. Four main tests are used by cooks preserving fruits as marmalades, jellies and jam:
- Thermometer test
- Saucer test
- Wrinkle test
- Flake test
Setting Point when Making a Jam or a Jelly
Two main differences between making a jam and a jelly are the yield of fruit and the temperature of setting. Compared to making a fruit jam, making a fruit jelly to spread involves discarding the fruit pulp before setting point and secondly the setting point of a jelly is a degree lower than setting point of jam at 105 degrees Celsius or 222 degrees Fahrenheit.
Thermometer Test
Thermometer test for setting point in making a fruit jam or jelly requires a Jam Thermometer. Before a jam thermometer is dipped into jam or jelly for testing the setting point, the jam-making equipment needs to be sterilised in boiling hot water. Once sterilised use the jam thermometer to take a temperature reading of the jam and jelly while in the preserving saucepan, without allowing the jam thermometer to touch the base of the saucepan. To recap on the setting point in Celsius when testing for a set using the thermometer test:
- Jelly has a setting point of 104 degrees Celsius
- Jam has a setting point of 105 degrees Celsius
In Economical Cookery (Morrison & Gibb, 1930), the advice on owning a jam thermometer is "The possession of a thermometer is a great help, because when it is registering 218 degrees Fahrenheit the jam maker knows that the boiling process is almost finished, and that the jam is on the verge of setting."
Saucer Test
If a jam thermometer is not owned in kitchen equipment, then the saucer test is a proxy test for the setting point when making jam. The saucer test can be used effectively to estimate the setting point In fruit jams: remove a spoonful of reducing fruit-rich liquid onto a very cold saucer and observe whether it appears to be jam-like in consistency as it cools on the saucer.
Wrinkle Test
Full-time food writer and home economist Maggie Mayhew writes in Jams, Jellies & Marmalades Step-by-Step Recipes for Home Preserving (Apple Press, 2008) about the Wrinkle Test which takes the saucer test outlined above further. After spooning the fruity preserve onto a cold saucer, Maggie Mayhew instructs for the wrinkle test "Leave to cool for 1 minuted, then push the preserve with a finger; the top should wrinkle. If it wrinkles only slightly, return the preserve to the heat and cook for 2 minutes more, then test again".
Flake Test
The Flake Test for testing for a set in jam is included in Home-Made Preserves section of Economical Cookery (Morrison & Gibb, 1930) and in Jams, Jellies & Marmalades Step-by-Step Recipes for Home Preserving (Apple Press, 2008) by Maggie Mayhew.
Testing for a set using the flake test involves looking at the movement of the jam on a wooden spatula or spoon as a observational method of testing for setting point. With practice the setting point of jam can be assessed as the jam cools on the wooden spoon two or more times. If the fruity preserve is able to slide off the wooden spoon, the flake test is a negative or setting point has not been reached.
Once the preserve can cling to the wooden spatula or spoon "if it forms small blobs or flakes" as the anonymous writer in Economical Cookery (Morrison and Gibb, 1930) explains as the positive outcome of the flake test, then the fruit jam has been cooked enough, reached setting point for a jam and a successful fruit jam home-made preserve has been produced.
Susan Morris - Susan Morris, BSc., MSc., Ph.D., Suite101 Topic Editor, business owner, gardener and Zero Waste Scotland volunteer.
