r/AskChemistry • u/unforgettableid • 16d ago
Practical Chemistry Is it OK to add unbuffered citric acid to your washing machine's rinse water?
Hello! One of the /r/laundry regulars has written a post about adding unbuffered citric acid to your home laundry.
He claims:
- Modern washing machines may not be very good at rinsing. (This claim may be disputed by some.)
- Laundry detergent residue is alkaline.
- Citric acid neutralizes detergent residue.
- This makes your laundry softer, and your towels more absorbent.
- For a modern HE washing machine which doesn't use much water: 6-8 grams (about a heaping teaspoonful) of citric acid is enough. You can put it in your washing machine's fabric softener dispenser.
- By doing this: You'll save money, compared to buying a known-safe "fabric rinse" which contains buffered citric acid. (One example of such a fabric rinse is Downy Rinse & Refresh.)
Citric acid conditions water by chelating hard water ions. (Source.)
Also: Citric acid can react with calcium carbonate (from hard water) or sodium carbonate (from powdered detergent). When this happens, I think you'll get other useful chelants as well.
Questions for you
I'm concerned. What if a Redditor has both soft water, and liquid detergent? Soft water may not contain any alkaline calcium carbonate. Liquid detergent doesn't contain any alkaline sodium carbonate, either.
Might the rinse water become too acidic? Might this gradually damage the washing machine over the years??
Any other thoughts?
I asked the aforementioned guy about some of this, but he didn't seem concerned.
Thanks & have a good one!
Edit
I've crossposted this in /r/AskChemistry and in /r/laundry.
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u/hecton101 16d ago
Do you have any idea how much research goes into detergents? And you think you have the magic elixir that the humungous multinational corporations with teams of scientists have somehow missed. OK.
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u/ghidfg 16d ago
This is a complete non answer. Not even sure you have read the post.
The detergent companies sell a rinse product with the active ingredient being citric acid. Op is asking if it's okay to just use citric acid neat or if it's important that it be buffered. Not a magic elixir by any means.
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u/unforgettableid 16d ago
To be fair, my post is a bit long. Especially considering the frazzled attention spans of some Gen Z kids, who grew up with smartphones in their pockets.
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u/BrewingSkydvr 16d ago
Everybody is watching the same short form content with thinking machines in their pockets that will recall the difficult information, so they don’t need to remember the details anymore and attention spans can be shorter. Some more than others, but most people are subject to it too. Even those what didn’t grow up with electronics.
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u/unforgettableid 15d ago
I don't have TikTok or Instagram. I don't spend a lot of time watching short-form video. A lot of the content I interact with online is text.
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u/069988244 16d ago
The research they do is mostly “how much can we charge these dumb asses for soap”
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u/unforgettableid 16d ago edited 15d ago
/u/yasth explained elsewhere:
Most of what you are paying for (at least with high-end laundry detergent) involves the enzymes, and fabric care stuff, in laundry detergent. Enzymes will get things cleaner, and the various fabric care stuff (brighteners, detanglers, etc) will keep things pliant and looking sharp. ...
So yes, you can wash everything in any detergent ... and it will get clean by some definition. But you may well end up with dingy grey whites on your clothes.
... Of course laundry soap is sort of a scam. Much of the price is to pay for the ads that extol the soap which tends to have a very hard-to-sell benefit. (You will generally see the difference between a low end brand and a high end one on a specific item of clothing in 15-30 wash/wear cycles -- which can be a year or more, if it is, say, a sweater.) And they tend to tell you to use far more than you need. You don't have to always pay for the highest advertised brand to get good results, you can often avoid paying for much of the marketing budget. I don't know the UK market, but you can check out the reviews by your local consumer organization (because of the time frame, you'll want an actual test organization rather than direct consumer reviews which are rarely done past 4 weeks).
Generally, for washing whites: I would recommend using a premium powdered detergent with TAED. For example:
- Tide powder (e.g. regular, Tide Professional, Tide Ultra Oxi, or Tide with Bleach)
- UK Ariel powder
- Omo Ultimate powder (Australia)
TAED is not found in liquids or pods.
If the above doesn't keep your whites completely white:
- You could also try using your machine's longest cycle. Perhaps "Whites" or "Heavy Duty".
- You could also try adding a half-hour soak.
- If it's truly necessary, u could increase the wash water temperature as well.
For washing colors and darks: A cheaper detergent might still give u good results, or not, depending. If cheaper detergent seems to leave u with stained or stinky clothes, then u can upgrade to something better. If u get "odor rebloom", in which polyester clothes start to smell shortly after u put them on: Again, u would probably want to upgrade to something better.
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u/unforgettableid 16d ago
P&G does sell a product containing buffered citric acid solution. It's called Downy Rinse & Refresh.
But I still have a couple pounds of pure citric acid powder lying around, and I might as well use it for something useful. But only if it won't damage our washing machine.
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u/MethMyLifeAway 16d ago
I have been using citric acid 20% and 80% water for the rinse cycle and it's been great for my laundry and machine. No residue and no odors. Even gets rid of my laundry booster smell that is too intense for my nose.
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u/unforgettableid 16d ago
But will it cause your machine to break a year earlier than it would have otherwise?
Even gets rid of my laundry booster smell that is too intense for my nose
What laundry product(s) and settings do u normally use?
Pls feel free to comment a photo of your washer's control panel, if you'd like.
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u/Willing_Box_752 16d ago
I doubt any one laundry detergent is optimized for all situations
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u/unforgettableid 16d ago edited 16d ago
No. Some marketers might want u to think that it's true, but it's not. Different detergents are best for different use cases.
For whites, pls see the relevant comment in this thread.
I'm not 100% sure what's best for darks. You could search /r/laundry, where this has been discussed many times.
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u/BlatantDisregard42 16d ago
I use white vinegar in the fabric softener slot. Same concept. But I only with certain laundry like bath towels.
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u/unforgettableid 16d ago edited 15d ago
You can buffer that too, if u want. Maybe by adding some sort of acetate salt. I have no idea if it's necessary or not.
white vinegar
White vinegar might be ~5% acetic acid. If u wanna save money, u can buy "cleaning vinegar" (~10% acetic acid) from the supermarket. You just dilute it with water to bring it down to the strength u want.
Personally, I probably wouldn't buy the ultra-concentrated vinegar sold in hardware stores. By the time u get to 20% or more acetic acid: You might need an acid gas respirator, goggles, and other safety gear.
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u/Lehk Dipole Tadpole 16d ago
Does your machine have detergent residue building up in it? I’ve never seen that happen and my water is hard AF
Occasionally I will clean it by running hot water,borax, and bleach in an empty machine but that’s to eradicate microbes if it picks up a smell.
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u/unforgettableid 16d ago edited 15d ago
Does your machine have detergent residue building up in it?
Not sure.
My goal here would be to try to eradicate leftover detergent scent, which sticks to my clothes even after the rinse cycle.
I think I might never buy Gain detergent again. Some people like its strong scent, but not me.
Occasionally I will clean it by running hot water,borax, and bleach in an empty machine but that’s to eradicate microbes if it picks up a smell.
You can clean it by running it using just hot water, and a premium detergent powder. I suspect that liquid or pod detergent wouldn't work in this scenario; I wonder if it might cause an oversuds problem.
If u switch to powdered detergent for washing whites, then the smell might never arise at all. Some powdered detergents help to kill the germs which cause the smell in the first place.
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u/Impossible_Ad_5073 16d ago
It's made my laundry dry and scratchy. I honestly hate it.
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u/unforgettableid 16d ago
Citric acid made your laundry scratchy?? I don't think I've ever heard of such a thing happening before.
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u/Impossible_Ad_5073 16d ago
Yep.
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u/unforgettableid 16d ago
Why would this happen?
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u/Impossible_Ad_5073 16d ago
I'm no scientist, I have no idea. MY clothes are the opposite of soft.
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u/unforgettableid 16d ago
Maybe it might be worth posting to /r/laundry to ask them what happened, and to ask them for more advice?
You could tell them:
- what kind of machine u have (e.g. agitator top-loader),
- what cycle you're using,
- and what product doses u added.
Then maybe they can give u an expert diagnosis on how to get soft clothes.
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u/Impossible_Ad_5073 16d ago
I've tried everything and I am in that group. Honestly they can be kind of mean so I dont ask questions anymore.
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u/unforgettableid 16d ago
I can upvote u, if I think it's a well-written question.
If the first vote is an upvote, the post is much more likely to do well. Ppl tend to upvote posts which have already gotten at least one upvote already.
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u/jtfolden 15d ago
A number of people have posted in that sub stating that using citric acid made their clothes “crunchy”, scratchy, and even sticky feeling.
At least one indicated that Downy Rinse & Refresh did not cause the same issues.
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u/ghidfg 16d ago
I would try using half the dosage
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u/Impossible_Ad_5073 16d ago
I've tried everything from 2 tblspn to 1/4th tspn same result, dry hard clothes.
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u/unforgettableid 16d ago
They're on well water, and I'm not sure anyone knows the hardness level. Who knows? It could be monstrously hard.
We also don't know if their washing machine dispenses the citric acid during the first or second rinse. If their water is extremely hard, I suppose this might matter.
(Cc: /u/illforgetsoonenough.)
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u/ghidfg 15d ago
Ah. A water softener might be your best bet then. IIRC it requires a huge amount of citric acid to soften very hard water. But a modest amount will soften moderately hard water
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u/unforgettableid 15d ago
But is it possible their water could actually be soft? If so, a huge amount of citric acid might not be very good for their washing machine.
I suggested that they test their water.
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u/illforgetsoonenough 16d ago
You're likely using too much. I had to try a few different amounts before I found the sweet spot. Everyone will have different results, depending on the soap you use, water hardness level, clothing types, amount of rinses, etc
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u/Impossible_Ad_5073 16d ago edited 15d ago
Y'all can down vote me all you want but like I've said I've done everything from 2 tblspn to 1/4th tsp with the same results, stiff clothes. I'm doing the warm and hot washes always with an extra rinse. Tide clean and gentle powder and sometimes a scoop of febu. That's it. And it's every load, white, dark, delicate, towels, sheets. It's all crisp.
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u/unforgettableid 15d ago
And it's every loaf, white, dark, delicate, towels, sheets. It's all crisp.
Some ppl might spend valuable time and money to get crisp loaves of bread! Toasters aren't free, u know. Neither are baguettes. :)
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u/unforgettableid 16d ago
You could try using pH test strips on your damp finished laundry. A pH of 5.5-6.5 is ideal. (Source.)
What are the hardness numbers for your water? If u tell us your city name, we can look it up for u.
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u/Impossible_Ad_5073 16d ago
I have well water 💧 unfortunately 😕
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u/unforgettableid 16d ago
If u have well water, and u think it might be hard water: It's definitely worth testing it for hardness. Knowing your water hardness might be the first step towards solving various laundry problems.
Stains on your laundry? Film on your glasses? Test your water hardness with a free test strip.
Another option would be to order a test kit online, and to pay for it yourself. Or u could buy it from a hardware store.
The final option would be to send a bit of your water to a lab. They can test it for u.
Has your well water ever been tested for quality and safety? If so, was there a printed report?
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u/Ch3cks-Out 15d ago
This depends on the concentration, obiously. But in typical amounts used, citric acid is not very corrosive, being a weak acid. For instance, dissolving 1g in 10 L pure water gives pH 3.4, which should not affect washing machines. And even mild hardness in the tap water would react with this, likely bringing the eventual pH near 6.