Clean the jars and lids with hot soapy water and rinse well. Drip dry upside down, then place in a low temperature oven (100°C), for 20 minutes.
Wash, peel and slice the beetroot into thinly sliced, 1-2mm thick discs. Bring to a boil in a large pot, the vinegar, water, sugar, salt, and spices. Lower the heat to a simmer, stirring to dissolve the sugar and salt. Add the beetroot slices and blanche for 1 minute.
Remove from the heat and stack the beet slices into your jars, packed tightly but not squashed, until they reach 5mm from the jar rim tops. Distribute the spices between the jars and pour in the brine. Tap the jar on the bench as you go to release any trapped bubbles, and completely submerge the beetroot, filling the jar very close, 1mm, from the top rim of the jar.
Seal, label, and date. Ready to eat in 2-3 weeks. These keep unopened in a cool dark place for up to a year. Once opened keep in the fridge and eat within 3-4 months.