How to use a candy thermometer
To use a candy thermometer correctly, put it in a small saucepan of cold water and bring it to the boil while you are making the candy mixture (usually a sugar syrup of some sort). When the syrup begins to boil, take the thermometer from the boiling water and put it into the syrup. Leave the thermometer in the syrup until the required temperature is reached. Watch the temperature closely once it reaches 90°C as it can escalate quite quickly. Don’t let the thermometer sit in the mixture after it has reached the desired temperature. Return it to the pan of boiling water; remove pan from the heat and cool the thermometer in the water.
Wash, dry and store the thermometer carefully; it’s best to store the thermometer wrapped in a tea-towel to protect it from damage.
Tip: Read the temperature with your eyes at the same level as the measuring liquid in the thermometer; looking from a different angle can result in an inaccurate reading.
How to buy a candy thermometer
Choose a thermometer that is easy to handle when dealing with hot mixtures. It should have a metal body and an adjustable clip or hook so it can be attached to the side of the pan. The most accurate thermometers hold the bulb up and away from the pan’s base.
Test the thermometer by placing it in a small saucepan of cold water; bring the water to the boil – an accurate thermometer will display 100°C. If the reading is higher or lower, take this difference into account when testing whatever you’re cooking.