Gat Kimchi — Mustard Leaf Kimchi (갓김치)

Ingredients

• 500 g gat (갓, Korean mustard leaf, Brassica juncea var. integrifolia), Yeosu-grown where possible; broad dark-green leaves
• 20 g coarse sea salt, for wilting
• For the paste
• 40 g gochugaru (Korean red pepper flakes), coarse grind
• 30 g saeujeot (salted fermented shrimp), roughly chopped
• 10 g garlic, minced
• 5 g fresh ginger, minced
• 10 ml fish sauce

Method

1. 1
   Trim the gat, removing any yellowed or damaged leaves, then cut into 5–6 cm lengths, keeping stems and leaves together. Scatter the coarse sea salt over the leaves and turn gently to distribute, leaving them to wilt for no more than 1 hour — the salt draws moisture from the tissue so the leaves soften without collapsing, and the stems retain that faint resistance that tells you they have not gone slack. Rinse briefly under cold water, drain, and press lightly to remove excess moisture; do not wring, or the stems will bruise and weep during fermentation.
2. 2
   Combine the gochugaru, saeujeot, garlic, ginger, and fish sauce in a bowl and mix to a rough, cohesive paste. Work the saeujeot in thoroughly so its brine is evenly absorbed by the dry flakes rather than pooling at the bottom of the bowl, which would give you an uneven saltiness once the paste meets the leaf. The paste should be deeply red and carry a pungent, saline smell — bold enough to meet the mustard compound intensity of the leaf.
3. 3
   Add the drained gat to the paste and, working with gloved hands, coat every leaf and stem thoroughly, pressing the paste into the cut surfaces so the seasoning grips the exposed interior of each stem rather than sitting only on the outer skin. This is where the dish lives or dies: the coating must be generous and even — sparse application leaves the mustard compounds unanchored, and the fermented flavour will be flat rather than the layered gochugaru heat and mustard bite that defines Yeosu gat kimchi.
4. 4
   Pack the dressed gat tightly into a clean, non-reactive container, pressing down firmly to eliminate air pockets so that the leaves ferment in their own liquid rather than drying out against exposed air. Seal and leave at room temperature for 2–3 days; the kimchi is fermenting correctly when bubbles appear at the surface and the container exhales a sharp, sour-pungent smell when opened.
5. 5
   Transfer to the refrigerator, where the cold slows fermentation so the bitter mustard compounds mellow and integrate gradually rather than tipping into sharpness. The kimchi is ready to eat after a minimum of 1 week of refrigeration; to assess readiness, press a leaf lightly with a fingertip — it should yield without collapsing and release a faint mustard aroma beneath the fermentation smell.