Place beetroot in a large saucepan and cover with water. Cover, bring to the boil, reduce heat and simmer 1 hour or until soft. Drain and let cool.
Meanwhile, combine all remaining ingredients in a saucepan. Bring to a simmer and cook about 10 minutes. Strain into a bowl and set aside, discarding solids.
Peel and coarsely grate beetroot. Mix with the vinegar mixture and set aside, covered, for 12 hours.
Fill sterilised jars with the beetroot mixture, leaving about 5mm headspace at the top of each jar. Seal with sterilised lids.
Line a large saucepan with a tea towel. Place jars on the towel then fill the saucepan with water to just below the lids. Cover, bring to the boil and boil 10 minutes. Store jars in a cool dark place, and in the fridge after opening.