Step 1

Preheat the oven to 120°C/250°F (without fan).

Step 2

Place the baking soda into a small oven-proof dish.

Step 3

Bake the baking soda for 1 hour.

Step 4

Remove the dish from the oven.

Step 5

Let the baking soda cool completely.

Step 6

Carefully transfer the baking soda to a sterilised glass jar. Take care not to touch the baked baking soda with your bare hands as it may irritate the skin.

Step 7

Make the lye water just before you need to use it.

Step 8

To make lye water for use in most recipes, you need to use a ratio of 1:4, i.e. 1 part baked baking soda to 4 parts water.

Step 9

So for 1 teaspoon of lye water, mix 1/4 teaspoon baked baking soda with 1 teaspoon water.

Step 10

Any unused lye water can be discarded down the kitchen drain.