A few years ago, Mrs. PVC Guy and I bought a house that needed love and attention. The trials and tribulations of fixing her up was enough to drive a sane man mad. If you haven’t read about the disasters of the pros that have come to work on our home, please feel free to read the PVC Guy story, if you want a good laugh.
What’s not included on that write up was the misfortune with a certain brand of appliances. As part of the negotiation with Mrs. PVC Guy to buy this humble home, I conceded to replace the old appliances (most needed replacement anyways) with brand new stainless steel appliances. While they look amazing, this particular brand has had problems (appliances are 3 years old) with the refrigerator, microwave / exhaust hood, the stove / oven and the dishwasher. Yes, those are all of the matching appliances we have. They have all had significant problems. But that’s a story for another time…
On one particular occasion, our dishwasher completely broke down. It would turn on, but not pump any water into the machine to start washdown. As (bad) luck would have it, our warranty expired just a few months before we had this problem so when I called <brand name redacted>, they declined my request to have a tech come out and fix the problem.
But since PVC Guy finds masochistic pleasure in reading the literature that comes with his appliances, he found a small loophole – the warranty on the electronics that control the dishwasher lasted for an additional two years.
Since I am sly like a fox, I called <brand name redacted> again and this time I insisted it was an appliance computer problem, not actually knowing if it was a faulty pump or mechanical part. They begrudgingly set up an appointment a few days later.
Come repair day, I meet the manufacturer’s rep technician and show him the offending dishwasher. His first response is that it’s a pump/mechanical problem and it’s not covered under warranty. Uh oh! Long story short, it ended up being a problem with the mother board which was covered under warranty. My maniacal plan somehow worked and I managed to get a free fix. It’s the first and only time I have been able to successfully get a product fixed under warranty and now I save all paperwork on big purchases.
Now that I am done tooting my horn, I will get to the point of this post. The service tech was kind enough to give me quite a few tips through the repair on how to properly maintain our dishwasher. Some were better than others, and most were specific to our model but one in particular stuck out to me that can be used by everyone.
That tip was to never use lemon or orange scented detergents.
It was crushing to me because I absolutely love the smell of clean dishes with that lemony scent wafting from my plates as I put everything in the cabinets. If I needed to stop using a particular brand or switch from liquid to powder or vice versa, that would not have been a problem. The detergent scent was the only thing I really cared about (aside from the cleaning aspect, of course.) I don’t care about the convenience of the packets vs. the pouring the powder – both are equally easy in my mind.
But this crushing news was terrifying and I am embarrassed to say it led me down a rabbit hole of research that I spent way too much time reading about. And this is what I found.
He was wrong.
The authorized tech support for this major appliance manufacturer was dead wrong.
In fact, many of the major appliance manufacturers suggest using citric acid to help clean your appliance and to run a citric acid wash periodically to help combat mineral build up.
GE’s view on citric acid: http://products.geappliances.com/appliance/gea-support-search-content?contentId=16899
Maytag recommends using citrus-based detergents for helping remove dish stains.
Whirlpool says, “Does your water have high iron content? Rewash dishes using 1-3 teaspoons (5-15 g) of citric acid crystals added to the covered section of the detergent dispenser. Do not use detergent.”
I was so relieved to have read this great news, directly from the manufacturers. But any information I found from metallurgical authorities gave me opposing information. In fact, citric acid is so corrosive that it is used in a process called passivation which is to literally make a metal “passive” to corrosive substances. Passivation involves an acid bath in a controlled environment which dissolves the outer layer of a metal, creating a slick, shiny surface that is more resistant to chemicals.
Christian Friedrich Schönbein discovered passivation in the 1800’s when he placed a piece of iron into diluted nitric acid and observed it dissolved. However, when he placed iron into a concentrated nitric acid and then returned it to the diluted acid, it made no reaction.
There are two important factors here with this experiment. The first, is that the main ingredient in diluted solutions (at least in this case) is water. Water is well known to corrode iron, a main ingredient of stainless steel. Between the water and the acid there will be rapid corrosion of stainless steel.
The second important factor is that “active” steel will de-passivate passive steel. Have you ever seen a piece of otherwise smooth and shiny steel form rust spots when in contact with other steel? It is counteracting the passivation process on the first steel.
But here is the major caveat.
Citric acid in your detergents fall under the category of diluted acid solutions, not concentrated. That therefore, is more dangerous to your stainless steel dishwashers, right?
Well, the good news is the stainless steel in your dishwasher has been passivated. On the surface (literally) you are safe, but scratches or imperfections can destroy that surface layer of protection, which will come with normal wear and tear.
And luckily, the amount of citric acid in your total wash will be small. The average water consumption of a dishwasher per cycle is 4 gallons. In one cycle, you will be using less than 0.1 oz of citric acid. If we assume only 2 gallons are used in the washing stage, then that equates to a citric acid solution of 0.00039 or 0.039%. That doesn’t strike me as a concerning amount of citric acid. Even an acid wash of 4 oz of citric acid (assuming you use 100% concentrate) will only be a 1.6% solution, nothing to be afraid of, especially considering lemon juice is about 6% citric acid.
The Final Ruling:
There’s no reason to avoid “citrusy” detergents, especially if recommended by the major appliance manufacturers. The logic makes sense that it could be destructive over time, but the volume of citric acid in a typical wash is unsubstantial.
You should probably avoid citrus washes everyday and use them sparingly.
And please, if you do decide to use “citrusy” detergents, make sure your flatware can tolerate it. Just because your dishwasher can handle your detergent, doesn’t necessarily mean your cutlery can.
Just for fun, I created a highly unscientific science experiment. You can read about my findings on the affects of lemon juice on stainless steel here.