With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.
Many people now use a dishwasher every day to make their lives easier; it’s a fantastic time saving appliance that actually uses less water and gets your dishes cleaner. But, there is a drawback; some people experience a problem with their glassware after its been through the dishwasher, and it becomes etched and discolored. In this article, we will look at this phenomenon in more detail; we will explain how this happens and how you can fix the problem.
Why Does Glass Coloring Occur?
Certain types of glassware can be affected by the dishwasher in different ways. Some glasses are imbued with a yellow or rainbow hued color that is caused by the formation of a silica film on the surface. The film actually follows the contours of the glass, the colors are more prominent along existing stress lines, and it cannot be easily removed using bleach, vinegar, or other more caustic cleaning chemicals. The only way to remove a silica film is to scrape it off with a sharp knife, but this can scratch the surface of the glassware, causing damage. Some glassware becomes cloudy; this can often be removed with white vinegar and vigorous scrubbing, but the results are mixed, and it may take repeated attempts. This can be a time consuming task, and the coloration issues in both types of glass will repeat unless the underlying problem is addressed.
Why Does Glass Etching Occur?
The glassware etching process occurs when the colored silica film problem is ignored and allowed to continue. The glass gradually becomes etched with a more pronounced cloudy appearance, and this cannot be cleaned away with any bleach or vinegar based cleaning product. This cloudiness cannot be removed with a sharp knife; the process is now irreversible, and to all intents and purposes, it is permanent. This etching is the result of metal ions that have been taken away from the glass resulting in a microscopically rougher surface. The exact causes of glassware etching in the dishwasher are the same as the silica film problem. The only difference is that more time has passed in order for the etching to take place.
Silica Film Explained
The development of a multicolored silica film that looks like oil on water follows the existing deformities present in the glass at the microscopic scale. This typically occurs when dishwashing with hard water that’s been softened, and the process is exacerbated in four ways.
- The dishwasher temperature is too high.
- Certain types of glassware are delicate and unsuitable for dishwashing.
- A dishwashing detergent with a high phosphate content is too aggressive to clean glassware in hard water that’s been softened.
- If the dishwasher is overloaded, the rinse cycle cannot work correctly, leading to deposits on the surface of glassware.
Once the etching damage has occurred, it can’t be reversed, and any affected glassware is ruined. But, the good news is that this process can be avoided or at least delayed by adopting the following five preventative measures.
- Set the dishwasher temperature to less than 140ºF.
- Wash delicate glassware by hand.
- Switch to a dishwashing detergent that contains less phosphorus.
- Avoid overloading the dishwasher to improve the results of the rinse cycle.
- Avoid using too much detergent and follow the detergent instructions carefully.
Dishwasher Detergent Issues
Most of the homes in our nation are supplied with hard water, and many products are made with this in mind. This applies to dishwasher detergents that are designed to aggressively remove hard water mineral deposits from your glassware and other dishes. This removes the aforementioned metal ions from the glass, and the surface becomes rougher and prone to further damage. The results on the glass are far more noticeable because you can see through the surfaces.
Making the water temperature changes mentioned above is a great way to minimize the damage. It’s also a great idea to look for a soft water detergent that’s designed to work with softened water for a gentler dishwashing experience. If you wash your dishes with softened water, you can use as little as a third of the max fill mark and still achieve great cleaning results.
Hard Water Dishwashing
When glassware is washed in hard water in the dishwasher, it can be covered in a thin film. This film is primarily composed of calcium and magnesium deposits, and these are also responsible for the water spots that you may see on shower stall screens and plumbing fixtures.
Hard water contains elevated levels of dissolved mineral content that can leave a layer of scale on surfaces over time. Once the water has evaporated, this mineral content remains, and it can be difficult to clean away. The surfaces can be cleaned, but the problem continues until the underlying hard water issue is addressed.
When glassware becomes covered with a film of calcium and magnesium, this can be cleaned away by soaking the piece in a mild acid. You can use white vinegar, and even citric acid will work to dissolve the hard mineral content. After soaking overnight, the glasses can be washed normally, and you should notice that the cloudiness has been removed. If the minerals are especially stubborn, you may have to repeat the soaking process and/or scrub the surface with a dishwashing pad.
Removing Hard Water from Your Home
The only sure way to remove hard water from your home for good is to install a water softening system. This will use an ion exchange process to switch out water hardening mineral ions, such as calcium, magnesium, and iron, for more benign sodium (salt) ions. This ion exchange process takes place on a tiny scale, and many people cannot tell the difference. But, if you are on a special zero salt diet or have an especially sensitive palette, the water could taste slightly salty. To deal with this problem, the water supply can be further treated to remove the salt from the water.
If you want to know more about how to remove hard water from your home, contact your local water treatment professional for expert help and advice today.