Start by sterilising your jars and placing saucers into the freezer (see instructions in notes below).
Put the apricots, granulated sugar, lemon juice, lemon rind and water into a preserving pan (or similar sized pan).
Place the pan over a low heat to gently dissolve the sugar. Stir with a wooden spoon until the sugar dissolves completely and no scratching sugar sound can be heard. Do not allow the mixture to simmer.
Once the sugar has dissolved, turn the heat up high and bring the pan to a rolling boil. Time for 12 minutes. Alternatively, use a digital thermometer and boil until you reach 105°C/221°F.
Remove the pan from the heat and test for set by putting a few drops of jam onto a chilled saucer and place in the fridge for 30 seconds.
Run your finger through the jam and if it crinkles and forms a gel then setting point has been reached. If not boil for another minute or 2 (depending on how close to achieving a set you are) and retest. Repeat until setting point has been reached.
Remove the lemon rind and pot up the hot jam into hot jars immediately using a ladle and jam funnel.
Screw on or attach lids immediately.
Allow to cool before serving (see post for storage information).