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What is Kansui used for and what kind of recipes use it?

kansui is an alkaline solution that is safe to ingest in the final concentration that it's used. It doesn't significantly alter the flavour of the final product but it does change the texture.

Typically it is used in some noodle preparations to create a slightly chewy noodle rather than the conventional soft noodle. It's also used in making certain dough pastires such as certain crepes. Typically Japanese crepes and Thai Khanom Buang or those street very crispy crepes that you may notice in Bangkok.

It was probably discovered by the Chinese and attributed to certain well waters. In fact some dishes proscribe the specific well to draw the water from. This is still a reality for at least one place in Vietnam, Hoi'an where there famous Cau lau noodle dish is a chewy consistency and is believed to be the water from a certain source. There is possibly some other aspects added but it's almost impossible to reproduce the dish. using something like kansui can bring the outcome very close indeed to the true Cau Lau.

Some alkaliser solutions use lime water where an amount of lime crystals are added to a jug of water and allowed to sit until the undissolved crystals sink to the bottom of the jug. The top crystal free layer is then drawn off and used in the specific recipe. You can see here that it isn't so important the kind of material that's used but rather the alkalising effect it has on the recipe. kansui uses sodium and or potassium carbonate(s) where as lime is Calcium oxide. The Chinese used to refer to their alkaliser stock solutions as "Lye Water" and would store it in vessels to keep it on hand at some stage it was then produced as a commodity and sold as a product. Kansui can also be called "Lye Water" or can be used as a crytalline blended powder or even simply sodium carbonate. The multiple component of the mixture described allows very concentrated solutions with the addition of a "buffer" (the sodium biphosphate component) to prevent the solution dropping in pH as carbon dioxide is absorbed from the other ingredients and possibly even the air itself.




Ingredients:
  • 55% sodium carbonate (Na2CO3),
  • 35% potassium carbonate (K2CO3),  
  • 10% sodium biphosphate dodecahydrate (NaHPO3.12H2O)
The percentages refer to relative weights in the final mixture.


Method:
So for 100 grams of Kansui you would mix:
  1. 55 gram Sodium carbonate
  2. 35 gram Potassium carbonate
  3. 10 gram Sodium biphosphate dodecahydrate.
This mixture will be stable indefinitely in a sealed glass bottle.

None of these compounds are restricted and are commonly available through various general scientific or chemical suppliers.

Your pharmacist may also be able to help you with this if you ask and take the recipe to the pharmacy.

Use:
5 grams dissolved in a small amount of water would allow you to make 500 grams (1 lb)  of a final dough mixture. {The kansui is generally used at a final content of 1%}

Online: This product is available online through Philam Food. It's sold as a liquid in bottles. On their site you must do a search to locate the product, use the search "Lye water" and about 6 choices will appear. This retailer is in Jersey City, NJ.,USA.