Cut off beetroot stem leaving about 2 inches. Place them in a pot, cover with water and simmer till slightly soft but still slightly firm. Test by inserting a skewer. Remove beetroot from pot and place into a bowl and save the water. Allow beetroot to cool and remove the top and base and skin them which is quite easy with the hands it just rubs away. Discard skins etc. You can slice the beetroot or leave whole depending on size.
Into another pot place about 6 cups of the saved beetroot water, vinegar and brown sugar. Simmer till sugar has dissolved. Place the jars and lids face down on a baking paper covered tray in the oven at 150 degrees for about 15 minutes. Remove from oven and turn right way up. Fill the jars with the beetroot slices being careful not to burn yourself. Pour beetroot water mix over beetroot to the top and place lids on tight.
Set jars aside in a safe place to cool. The pop bit in jar lids will pull down as they get cool. I like to keep them in the cupboard for a few weeks minimum to infuse the vinegar flavour before eating.