8 cups cold water
14 ounces of vegetable offcuts and peelings from 4 different kinds of vegetables such as carrots, daikon, Chinese cabbage, pumpkin, turnip, etc.
2 slices of root ginger
3/4 ounces of konbu
Place all the ingredients in a pan. Bring to the boil over a medium heat, then simmer until reduced by half.
Strain through a fine sieve and use as needed.
The dashi will keep in the fridge for a few days and in the freezer for up to 3 months.