Removing the scum marks on the top of your cup of Tea or Coffee

Scum Oil Film in Tea and Coffee

When you make a nice hot cup of tea or coffee, you may have noticed a layer of scum floating at the top which has a bit of an oily appearance. This scum can form a type of grime which sticks to your cups over time, especially if you leave the cups for extended periods of time with the tea or coffee in them.

Like many people, you may be wondering what it is. Scientists have been researching the topic extensively and in 1994, Researchers at Imperial College Chemistry Department made a bit of a breakthrough:

"Only if you know what scum is and how it forms," says British Chemist Professor Michael Spiro, "can you eliminate it. And tea drinkers do want it eliminated."

The research shows that the scum on tea is composed primarily of calcium carbonate (about 15-25%) and the rest is a mixture of complex organic chemicals or minerals. Others research has stated it is also due to the due to the oil in the tea leaves. It may also be a much bigger problem if you live in a hard water area.

How you can stop the scum-like film forming in your tea and coffee

We have a range of devices that will be suitable for removing the scum and film in your tea and coffee. However we have grouped them into Good, Better and Best. Here is a quick summary of your options:


Brita Taps1) Good: Brita 3-Way Tap Filter Systems


The Brita Water Filter Systems are an effective way to remove the scum in your tea. When the carbonate hardness turns into chalk as a result of being boiled, the chalk absorbs the tea and then changes colour which leads to the unsightly appearance and bitter taste. The Brita P1000 cartridges work by decarbonising the water, meaning that the tea becomes crystal clear, better flavour develops and the scum stains do not appear. Good hey? The Brita P1000 is available with a great range of Brita 3 Way Dispenser Taps.

Click here to watch the video by Brita's Tea expert, Jane Pettigrew.


Proline Plus Reverse Osmosis System2) Better: Proline Plus Reverse Osmosis System


The Proline Plus Reverse Osmosis System is a superb entry level reverse osmosis system. Reverse osmosis works by pushing the water through a very tiny membrane and therefore removing scale and all impurities in water to a very high level. In fact many bottled water companies use the same process to purify bottled water. Now you can have this on tap in your home. It is the best solution for not just removing scum and oily film in tea or coffee, but also chemical disinfectants, heavy metals, fluoride and several other impurities in water.



Pure-Pro3) Best: Pure-Pro 6 Stage Alkaline Reverse Osmosis System


The very best solution available to you is the Pure-Pro 6 Stage Alkaline Reverse Osmosis System. This is a fantastically well-designed 6 stage system and includes an alkalne filter to raise the pH of the water to optimal levels of between 8.5 to 9.5.

The system will produce ultra-pure water and will totally eliminate scum and oily film in tea and coffee as well as give you top quality filtered water. The very best system on the market!





Now you have solved the problem, enjoy a lovely clear cup of tea!


You will enjoy your tea even more if you follow these basic steps to make the perfect cuppa!

1. It goes without saying that you must use one of the Osmio recommended water filter systems for the better tasting clear and lovely tea! Our systems will remove the scum and scale, oily films as well as all impurities you will have great taste, smell and appearance for your tea.

2. Depending on the kind of tea you are making, the temperature you should boil the water to will vary. Normal black tea should be boiled to 95°C (do not over-boil), but herbals teas such as peppermint or green tea should be boiled to around 70°C. 

3. Ensure your tea is high quality and stored in an air tight container in a cool dry place so it does not get damp and away from any cooking smells.

4. Be patient and let the tea brew for around 6 minutes. This time can vary depending on the type of tea and the size of tea leaf. Gently stir the tea while brewing. If you are adding milk and sugar, swirl the tea before adding these. Allow it to cool to around 50°C before drinking it to allow all the flavours to pour out.


There we go, the perfect cup of tea!