Cut off the top and bottom of the celeriac, then peel the sides. Rinse the celeriac, knife and chopping board, and slice the celeriac into 2½ cm thick slices. Set the mandoline to a thickness of 1 mm and slice the thick slices into thin, long strips using the mandoline.
Toss the strips with salt in a large bowl and leave to stand for at least 1 hour. Give them a stir a couple of times and finally drain them in a sieve.
Place the celeriac in a preserving jar.
Bring the vinegar, sugar and water to the boil with the peppercorns, boil the brine for a couple of minutes and pour the hot brine over the celery in the preserving jar.
Leave to cool with the lid on, then place in the fridge, where it will keep
for up to 3 months.
