1. Wash and peel the carrots, then grate them into thin strips using a grater, mandoline or, if you have one, a food processor capable of making thin strips.
2. Weigh the carrots and add salt.
3. Place the carrots in a bowl with the ginger, garlic, coriander seeds, orange zest and orange juice.
4. Massage the mixture thoroughly and leave to stand for 5–10 minutes until the carrots begin to release liquid; massage again.
5. Transfer everything to a sterilised preserving jar and press the carrots down firmly so that they are covered by their own brine. Fill only to about 3–4 cm from the rim.
6. Place the jar on a plate and leave it to ferment at around 20 °C in a cool, shady place for 2–3 days. Open the jar daily to release carbon dioxide.
7. Taste the carrots after 2–3 days. Once they have a fresh tanginess, place the jar in the fridge and the fermentation process will stop.
Store in the fridge and they will keep for a couple of months. Ensure the carrots are always covered by brine.
Delicious in sandwiches, on smørrebrød and in salads, and as a side dish at lunch or dinner.