Prepare Cabbage (Time: 0-150 minutes):
Cut 3kg napa cabbage lengthwise into quarters, leaving core intact to hold leaves together.
Dissolve 1 cup sea salt (not iodized) in 8 cups water. Soak cabbage 2 hours, turning every 30 minutes.
Rinse thoroughly under cold running water 3 times. Drain in colander 30 minutes.
Make Porridge (Time: 150-160 minutes): Mix 2 tbsp sweet rice flour with 1 cup water. Cook over medium heat, stirring constantly, until thickened to paste consistency (about 5 minutes). Cool completely.
Make Kimchi Paste (Time: 160-175 minutes):
Blend 1/2 Asian pear, 1 onion, 1 head garlic (10-12 cloves), 2-inch piece ginger until smooth.
In large bowl, mix pear puree with 1 cup gochugaru (Korean red pepper flakes), 1/2 cup fish sauce, 1/4 cup salted shrimp (saewujeot), cooled porridge, 1 tbsp sugar.
Prepare Vegetables (Time: 175-185 minutes): Julienne 1 daikon radish into matchsticks. Cut 8 scallions into 2-inch pieces.
Mix Vegetables with Paste (Time: 185-195 minutes): Wear gloves. Mix radish and scallions into paste until evenly coated.
Stuff Cabbage (Time: 195-225 minutes): Spread paste between each cabbage leaf, starting from outermost leaf and working inward. Be generous with paste.
Pack and Ferment (Time: 225-240 minutes):
Pack kimchi tightly into clean glass jars or food-grade plastic containers, pressing down to remove air bubbles.
Leave 2-inch headspace for expansion.
Leave at room temperature (18-20°C) for 24-48 hours until bubbly (taste after 24 hours).
Refrigerate for minimum 2 weeks before eating for best flavor. Kimchi keeps for months.