Compressed Celery

• 1 bunch celery
• 100 ml (3½ fl oz) kombu extract

Separate the celery stalks and discard the leaves and their small branches for this recipe (you can pickle these, or use them elsewhere). So using just the thick stalks, peel the outside with a vegetable peeler and cut into 12 cm (4½ inch) lengths.

If you have a vacuum-sealer system at home, di