Lye Water

How to make homemade lye water for use in recipes such as Pretzels and Mooncakes. Recipe with step-by-step photos.

homemade lye water on wooden board

What is Lye Water?

Lye water is a food-grade alkaline water used in some recipes to help with texture or colour.

For example, lye water gives Pretzels their signature dark brown colour and taste. For Mooncakes, a small amount of lye water is used to give the dough a deep, golden colour.

homemade lye water in glass bottle

Where to Buy Lye Water

Lye water is readily available in Asian grocery stores in some countries, but not in others. It is often labelled as “Kansui” on most Asian packaging, and it is essentially a clear solution which contains potassium carbonate.

Due to its potency and irritant factor, lye water is banned in some countries. At certain concentrations, lye water can irritate the skin, which is why it is not readily available everywhere, and why lye is often sold with strict instructions for safe handling.

Homemade Lye Water

A good substitute for lye water is a simple homemade lye water.

You can make your own lye water at home with just baking soda and water. Baking soda is an alkaline substance, and baking the baking soda intensifies its alkaline properties.

So a solution containing baked baking soda will be more alkaline than just using normal baking soda.

lye water substitute

Recipe for Lye Water

To make the lye water for use in most recipes (such as for Mooncakes), use a ratio of 1:4 (1 part baked baking soda : 4 parts water).

So if a recipe requires 1 teaspoon of lye water, simply mix 1/4 teaspoon of baked baking soda with 1 teaspoon of tap water.

Other recipes might specify what concentration of lye water is required. For example, when making my Soft Pretzels, I use a ratio of 1:2.

How to Make Lye Water

Step 1

Spoon the baking soda into an oven-proof dish, preferably large enough so that the baking soda can be spread out in a thin layer.

Bake for 1 hour at 120°C/250°F (without fan).

baking soda in baking dish

Step 2

Let the baking soda cool completely before transferring it to an air-tight container for storage, and label it accordingly. I like to use a glass spice jar.

Step 3

Make the lye water just before you need to use it. Simply dissolve the baked baking soda in some cold water.

Precautions When Making Lye Water

Food-grade lye water is fairly mild and is safe for cooking. However, people can react differently when their skin comes into contact with lye water.

Hence, to be on the safe side, avoid touching the baked baking soda with your bare hands, and wear gloves if you are a bit clumsy in the kitchen.

Recipes Using Lye Water

The following recipes use Lye Water:

Mooncakes with Lotus Seed Paste and Salted Egg Yolk

Soft Pretzels


Lye Water

5 from 8 reviews

  • Author: Thanh | Eat, Little Bird
  • Prep Time: 5 minutes
  • Cook Time: 1 hour
  • Total Time: 1 hour 5 minutes
  • Yield: 1/2 cup
  • Category: Pantry
  • Method: Oven
  • Cuisine: Chinese

How to make homemade lye water for use in recipes such as Pretzels and Mooncakes. Recipe with step-by-step photos.



To Bake the Baking Soda

  1. Preheat the oven to 120°C/250°F (without fan).
  2. Place the baking soda into a small oven-proof dish.
  3. Bake the baking soda for 1 hour.
  4. Remove the dish from the oven.
  5. Let the baking soda cool completely.
  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.

To Make the Lye Water

  1. Make the lye water just before you need to use it.
  2. 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.
  3. So for 1 teaspoon of lye water, mix 1/4 teaspoon baked baking soda with 1 teaspoon water.
  4. Any unused lye water can be discarded down the kitchen drain.

Kitchen Notes

If you need to use lye water only occasionally, I recommend baking about 1/2 cup of baking soda at a time and storing it in a glass jar or glass spice jar. The baked baking soda keeps fairly well indefinitely in a sterilised jar, but make sure you label it accordingly.

All recipes on this website state temperatures for a regular oven (i.e. a conventional oven without fan). If you have a convection oven with a fan, please consult the manufacturer’s handbook on how to adjust the temperature and baking time accordingly.

To convert from cups to grams, and vice-versa, please see this handy Conversion Chart for Basic Ingredients.

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  1. Jenny 14 September 2022

    Thanks for the clear instructions! I live in France and can’t find lye water here either.

  2. Angie 2 October 2022

    Just used your recipe today. It worked great! Thanks!

  3. nuoc tro tau 5 November 2022

    Food grade lye water is a potent liquid alkaline used to make traditional ramen noodles, giving them their springy texture

  4. Sandra 18 January 2023

    Very useful recipe. Thanks!

  5. Kim Ann 30 March 2023

    Very helpful. Thanks! Can’t find lye water where I live either (Germany).

  6. nuoc tro tau 29 July 2023

    Chinese ash water is a special condiment that helps balance the pH, create flexibility for the crust with starch and protein, and bring beautiful flavor and color to the product.

  7. Kelly Ronayne 10 August 2023

    Hi, what is the pH of the finished baked baking soda lye water? I’m wondering how it compares to true lye, especially for the purpose of making hominy and masa from maize. The Georgia University State Extension Office has a recipe for canned hominy using baking soda instead of lye, but it talks more about the baking soda being used to remove the hulls from the maize, while the original lye was also used to make the niacin in the grain bioavailable, deactivate mycotoxins and improve the texture of the grain.

    • Eat, Little Bird 20 August 2023

      Hi Kelly,
      Baked baking soda is not as potent as “true lye”. I have not tried making hominy and masa, so I can’t comment on whether these recipes work with baked baking soda. But certainly for pretzels, mooncakes and ramen noodles, this baked baking soda produces the results which I am looking for. I would be curious to try these recipes using true lye water, but it is, unfortunately, not available where I live.

  8. Nora 19 September 2023

    Very helpful, thanks!

  9. Judy 25 September 2023

    Thanks for the recipe

  10. Janie 25 September 2023

    So easy to make! I live in Germany and wanted to make your mooncake recipe but I couldn’t find lye water where I live either. Thanks so much for everything!

  11. Tom 28 September 2023

    I used this recipe to make mooncakes and they came out perfect with very nice color.

  12. David 28 September 2023

    Great recipe

  13. Kimmy 28 September 2023

    I made this baked baking soda last year and I was still able to use it this year with very good results!