Pour the liquid from the beetroot, the vinegar and water into a saucepan
Heat over a low temperature until tepid
Pour over the beetroot and seal the jar
Place the jar into a sous-vide cooker and bring the temperature up to 60° Celsius ***
Once the temperature has been reached, set a timer for 30 minutes
Remove from the cooker and place onto a rack to cool completely before opening or storing
Refrigerate once opened
Notes
* wear gloves if you do not want to stain your hands ** the longer your beetroot spends in the salt, the softer it will become *** you can use a pot on the stove with a thermometer but I find this easier to maintain the temperature