Thursday, September 21, 2023

Descaling for home appliances?

 Also, what are the consequences if we don't descale - the iron, airpot works fine. 

For Nespresso, I read that they will take longer to heat or water will be cold, coffee will be bitter. 

They still heat up. 

How do I know if the 1) to 3 items need descaling?  

Thanks again. 


Thank you Mr Chen Ko for your thorough water blog. 


Hope you can advise me if the following needs regular descaling if used in Singapore with its soft water:

1) Iron with water container, 

2) Thermal air pot or  kettle 

3) Nesppresso?


So far we have not descale any of our electric water containers. 

At most, I  see the ageing water heating rod turned orange in our kettle.  

Thank you for your kind sharing. 




Dear Kim

Here are a few thoughts regarding the issue.

  1. Hardness in water is due mainly to calcium and magnesium initially dissolved in water. Due to heating, these calcium & magnesium react chemically with other substances in water to form your solid scale.

  2. Toxicity of scale is not an issue so we can leave that out of the equation.

  3. However, scale does adversely affect heat transfer in heating equipment so a thick layer of scale means that you need more power to heat up the same amount of water or beverage. In industry, it is a standard practice to descale large-scale heating equipment to minimise heating costs. For domestic purposes though, I hardly hear of such a practice as the economics probably do not work out favourably. Your equipment probably fails before the scaling becomes problematic.

  4. As you rightly pointed out, the water in SG tap water is soft so the scaling problem is somewhat less severe than in other countries consuming hard water in their homes.

  5. Though scale is somewhat stable normally, it can break up and dissolve in an acidic environment. Incidentally this is one way to perform descaling. You mention about coffee so yes, if your coffee has the right level of acidity (this applies to tea too), the scale can dissolve into your beverage and most likely affect its taste.

  6. Long story short, if you believe the scale is affecting the taste of your normally superb coffee/tea, go ahead with descaling. However, I am unsure of the economics of such a move compared to simply getting a new machine.

Good luck!

Figure: Nespresso machine


Friday, August 04, 2023

The History of Water Quality in Singapore: Talking about Science from a Historical Perspective (or is it History from a Scientific Perspective)

I recently had the privilege to be invited to provide a training session to the docents of the National Museum of Singapore. The topic was on the history of water quality in Singapore. Admittedly, history has never been my forte since my secondary school days. In fact, I used to thumb my nose at the subject. However, water quality is and it has always been my pleasure to share about this topic with all manner of audience and even from a historical perspective.

Talk at National Museum of Singapore - The History of Water Quality Click here for the full video of the talk.

Docent training at National Museum of Singapore: The history of water quality in Singapore
Click here for the full write-up of the talk.


Wednesday, March 01, 2023

Being Interviewed on Talking Point shown on Channel 5, Nov 2022: Is Bottled Water Worth Your Money?

Despite the title of this episode as given above, I was not sought for my views on bottled water. Instead, I gave my take on alkaline water which appeared in a segment in the middle of the show. In a nutshell, my stand has been consistent with what I have been saying on this blog all this while. (Check out an earlier post for a more in-depth discussion: Why I wouldn't be drinking alkaline (aka ionised) water.) There is much well deserved skepticism regarding alkaline water. Until these issues are cleared up, the claims regarding alkaline water continue to sound nebulous.