Measure out your chocolate, then set aside ⅓ of the chocolate to create the seed.
Place the first ⅔ of the chocolate in a bain marie, double boiler or a metal bowl set over a saucepan with 1 inch of hot water in it. The water should not be boiling and should not be touching the bottom of the metal bowl.
Melt the chocolate very slowly, stirring occasionally but always checking the temperature. You want it to reach 55°C (131°F) which is usually just after all the chocolate has melted.
As soon as the melted chocolate reaches this temperature, remove the metal bowl from the heat and place on a tea towel to halt the heating.
Tip your ⅓ of chocolate seed into the molten chocolate and stir in very quickly and firmly so that the chocolate melts completely. You need the temperature to reduce to 27-28°C (80-82°F). This could take about 10 minutes of constant stirring. If by this stage your seeded chocolate has not completely melted you need to remove the lumps as these will impair the finished temper of the chocolate.
As soon as the temperature has dropped to 27-28°C then place the metal bowl back on the heat and bring back up to 31-32°C (88-89°F). It can take just moments so keep stirring with the thermometer at hand to monitor.
When your chocolate has reached 31-32°C it is now in temper and is ready to use.
If you are able to keep the chocolate between 31-32°C whilst you are using it then that is ideal. However, if not then you need to work very quickly coating your truffles or filling your moulds otherwise the temperature will drop out of temper. As the chocolate cools it will thicken and become impossible to manipulate.
If you let your chocolate rise above 31-32°C then you will have over-tempered the chocolate and will need to start again by raising it to 55°C (131°F) and taking it from there.