Prepare the Red cabbage and cut it into small pieces.
Pour 500ml Water into a pot.
Put the Red cabbage pieces, cranberry powder (10g) and salt into the saucepan.
Boil until it froths.
Boil it for 20mins on a low heat.
Turn off the heat and mix in baking soda until you get the right color. Make sure to store it in fridge in a clean airtight container and use the dye within 2~3days.