Laundry soap and hard water questions

Discussion in 'Lye-Based Soap Forum' started by szaza, May 30, 2019.

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  1. May 30, 2019 #1

    szaza

    szaza

    szaza

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    Hey everybody!

    So... I've recently gotten back to the idea of laundry soap making as I read some of the experienced soapmakers on here do it.
    I actually got into soap making because I wanted to make laundry soap, but got scared by some horror stories online and decided to stick with making body soap.
    I've used 'eco friendly' laundry detergent for a few years, but I feel it doesn't clean properly and I had to throw out a bunch of shirts because they smelled sweaty (even though I didn't overly sweat in them, it just didn't wash out and accumulated over time). I went back to regular high power detergent, but would like to have a more biodegradable alternative that washes properly and I'm hoping laundry soap can do just that.
    The problem is the water here is quite hard and I'm afraid of ruining the washing machine. We're renting, so I'm also not going to invest in a water-softening system..
    With my body soap I barely get any soap scum if I add 2% of citric acid, so I thought I could make a laundry soap with 4% citric acid to be on the safe side (plus extra lye to react with of course!)
    The recipe would be a 100% coconut oil soap with 95% NaOH and 5% KOH. I'd use a superfat of -1 or maybe even -3 with a high water soap, like a 25% lye solution so if the negative superfat doesn't get cancelled out by the lye impurity, the excess lye can move out and react with air to form sodium carbonate like in the lye heavy Castile soap thread (IIRC there was someone who suggested it was because of the extra water that the extra lye could migrate out of the soap to react with air) I'd shred the soap and mix it in equal parts with washing soda as per DeeAnna's website https://classicbells.com/soap/laundrySoap.asp
    My questions:
    1. Does this seem like a reasonable recipe for laundry soap for a hard water environment?
    2. How do I check the washing machine for soap scum build up?
    3. How much citric acid would be too much? I think I read on DeeAnna's website that most people stay under 2% because at higher percentages it can form some crystals, but I don't really mind how my laundry soap looks, just how it functions. Is there a disadvantage of using more CA other than crystal forming? https://classicbells.com/soap/citricAcid.asp
    4. I always use vinegar in stead of fabric softener. Would that still be a good idea when using laundry soap?

    A big thank you to all of you for reading. I know this topic has been coming back a few times and I might be a bit stubborn in wanting to try laundry soap in hard water but I'm just really not happy with my detergent at the moment and want to find something better.
     
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  2. May 30, 2019 #2

    earlene

    earlene

    earlene

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    I've never used Citric acid, so can't address that.

    But I have used vinegar and do have an opinion about it. I quit using it because it just seemed wasteful. Even with a High Efficiency washing machine that uses less water than the traditional washing machine, the water dilutes the vinegar so much, I don't believe it is very effective anymore. After all, the vinegar starts out at only 5% concentration (in the the vinegar I buy) so adding that to the rest of the water, in the washer, just really dilutes it a lot.

    When clothes smelled strongly of sweat, I found it more effective to spray vinegar directly on the smelly parts & let it sit for a bit before tossing into the washer. Of course some fabrics might be more sensitive to a direct vinegar spray, but for the most part, I don't have any use for sensitive fabrics any more in my life. (I did when I was a young and took things to the dry cleaners, but I am beyond that, now.)
     
  3. May 30, 2019 #3

    szaza

    szaza

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    Thanks for the tip of spraying vinegar directly on the clothes! Never thought about that[emoji16]
     
  4. May 30, 2019 #4

    DeeAnna

    DeeAnna

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    I think the better question to ask about using citric acid in soap is whether the citrate in the soap will be effective at reducing soap scum in the laundry water. IMO, it can't hurt, but it's not really the answer for a laundry soap. The washing soda or borax in most laundry mixes is the key ingredient that softens the water.

    A chelator like citrate (citric acid + NaOH) or EDTA is pretty effective at treating small amounts of water hardness ... like the water on your washcloth when you bathe. When you wash clothes (or dishes in a sink full of water), there is a lot more hard water minerals for the chelator to treat and that becomes difficult if not impossible.

    Let me "geek out" for a bit to show you why --

    ***

    Let's say you make laundry soap with citric acid at 3% of the total soap weight. That means there are 3 grams of citric acid for every 100 grams of soap.

    When I made my own laundry soap blend, I used about 15 grams of actual soap per load of laundry. With citric acid at 3% of the soap, that means 0.45 grams of citric acid (converted to citrate) ended up in each load.

    I estimate this amount of citrate can chelate roughly 0.23 grams (230 milligrams) of water hardness, assuming the hardness is all calcium carbonate.

    The US Geological Survey says --
    "...0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard..." Source: https://www.usgs.gov/special-topic/water-science-school/science/hardness-water

    Assume my water hardness is 100 mg/L (somewhere in the moderately hard range.) The chelator in the soap could remove the hard water minerals in 2.3 liters (about 2.5 quarts) of this water, assuming every bit of the chelator reacts only with the hard water minerals.

    ***

    "...Most high-efficiency washers use only 15 to 30 gallons (56.8 to 113.6 L) of water to wash the same amount of clothes as older washers (29 to 45 gallons per load (109.7 to 170 L). The most efficient washers use less than 5 gallons (18.9 L) per cubic foot of capacity...." Source: https://www.home-water-works.org/indoor-use/clothes-washer

    I have a high efficiency washer, so I'm going to assume the actual water per wash load is 56 liters (15 gallons). To soften this water with 15 grams of soap, I would have to increase the citric acid content in the soap recipe from 3% to --

    56/2.3 X 3% = 73% citric acid

    73% seems like an awful lot of citric acid to add to soap.

    ***

    Very roughly speaking, washing soda can remove about its own weight in hard water minerals.

    My laundry mix recipe calls for a 1:1 ratio of soap and washing soda. So for every 15 grams of soap, I would also add 15 grams (15,000 milligrams) of washing soda per load.

    If the water has 100 mg/L of hardness, that 15,000 milligrams of washing soda will soften about 150 liters of water.

    That's more washing soda than is strictly needed for treating only 56 liters of water per load. The left-over washing soda has another important job to do, however. Washing soda is also used to increase the pH of the water so the soap is more effective as a cleaner.

    Remember soap needs to be alkaline to remain as soap, and water is usually neutral to acidic. If the washing soda isn't there to raise the pH of the water, the soap will attempt to do that job, and thus the soap will be less effective as a cleaner.

    ***

    edit: And this brings me to my pet peeve about including baking soda in a laundry soap mix. Washing soda is much better in a laundry mix than baking soda, but a lot of the laundry soap recipes you can find on the 'net call for both of them.

    Washing soda has a pH of about 11. Baking soda has a pH of about 8. Lye-based soap has a pH in the 9 to 11 range. Washing soda and soap have similar pH values. Baking soda pH is much lower.

    Baking soda will never raise the water pH sufficiently high enough to let soap do its job efficiently as a cleanser. Only washing soda can raise the pH high enough.
     
    Last edited: May 30, 2019
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  5. May 31, 2019 #5

    szaza

    szaza

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    I love it when you geek out @DeeAnna !:D I realized my mistake after your first sentence (of course a few percentages of citric acid aren't going to do much in bucketloads of water), but I thoroughly enjoyed reading your explanation on why and how citric acid/sodium citrate won't do the trick for laundry soap.

    After reading your post I decided to figure out how hard my water is exactly and how much water our laundry machine uses per load to calculate how much water softener I'd need and apparently it's all a lot better than I expected.
    First of all and most interestingly, the cut-offs for what is considered 'hard' water seems to be completely different here in Belgium and the Netherlands than in the US. According to Dutch Wikipedia, 0-20mg/L is very soft, 20-40mg/L is soft, 40-60mg/L is regular, 60-80mg/L is moderatly hard, 80-120mg/L is hard and >120mg/L is very hard. The Belgian water company uses the same cut-offs but only measures them in °F and °D. Quite the difference from the US Geological Survey! (Americans must have crazy strong bones! Do you ever break something or do you just walk out of accidents like nothing happened:eek:)
    Secondly I found out that although our area generally has moderately hard/hard water (80mg/L), our house gets service from a regional water softening installation, which means we're supposed to have regular water (50mg/L). Though judging by how often we need to clean the shower head the water coming out of our tab is probably hardened by all the limescale that has built up in the pipes over the decades (we live in a really old house with really old pipes and the water softening installation has only been there for a few years). Anyway, our water is never going to be near as hard as US hard water and our washing machine only uses an average of 45L/load. Even if I would assume we had 80mg/L water hardness and I'd use a longer program that uses, say 55-60L/load I wouldn't need more than 5g of washing soda to soften the water, so with a regular 50/50 soap/washing soda recipe and using 30g/load I'd probably still be safe.

    Just theoretically though, say I'd have a water hardness of 100mg/L and a washing machine that uses 150L/load, I'd need 15g washing soda just to soften the water. Would it make sense to make a laundry mix that is 1 part soap and 2 parts washing soda and use 45g/load so you still have 15 grams soap and enough washing soda to soften the water and some extra higher the pH?

    One last question, since a higher pH makes the soap work better, I assume a -3 superfat wouln't be all that bad, as long as I avoid touching the laundry mix by using a measuring cup or spoon to scoop it out?

    Off to the soaping kitchen for me! Time to make some laundry soap :D
     
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  6. Jun 1, 2019 #6

    DeeAnna

    DeeAnna

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    "...Would it make sense to make a laundry mix that is 1 part soap and 2 parts washing soda and use 45 g/load..."

    I agree with your thinking. Nice research and analysis!

    "...since a higher pH makes the soap work better, I assume a -3 superfat wouldn't be all that bad..."

    It is a moot point, to be honest. You can do -3% or zero superfat as you see fit. Excess lye in the grated up soap is going to react fairly quickly with carbon dioxide in the air. It will become washing soda.
     
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  7. Jun 9, 2019 #7

    Rahmi

    Rahmi

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    What's the reason for doing the negative SF?
     
  8. Jun 9, 2019 #8

    earlene

    earlene

    earlene

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    To ensure there is not fat left in the soap to go into the laundry. Most lye is not as pure as 100%, even when you first buy it, so even a 0% SF setting on a lye calculator is probably not really zero SF if you don't test your lye's purity before each use. Lye absorbs ambient water from the air every time you open it, by attraction.
     
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  9. Jul 11, 2019 #9

    emi

    emi

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    I hope this isn't so late it is considered necro-posting. I've been reading up on all the laundry detergent posts and wanted to ask about using EDTA. I have both Di and Tetra EDTA in powder form and understand I should use Tetra. I live in California, have hard water, and do not have a high-efficiency washing machine. I read the treasure trove of information on your website including the page on EDTA https://classicbells.com/soap/EDTA.asp and wanted to ask about the amount of EDTA I should use for combatting the hard water. Is the 0.05% recommendation for bar soap also apply to soap intended for laundry detergent? Will this have any effect on the huge amount of water it will be in? If it does also apply, I will use the higher 0.5% since I don't know exactly how hard my water is, but pretty sure it's on the very hard side based on the intense amount of residue on my shower walls. I'm going to start with a small batch of coconut bar soap to make the laundry detergent soap. I'm also planning to make some sodium carbonate by cooking baking soda for an hour since I happen to have a lot of it. (does that really work or should I go buy some? https://wellnessmama.com/76866/washing-soda/) I was going to do the 1:2 ratio of grated then blitzed soap to sodium carbonate per szaza's calculation and use 45g per full load since mine is also a non high-efficiency washer. (I know I need to invest in one asap!) Or is that 2:1 ratio not necessary since I'm using EDTA?

    This is my recipe so far for the bar soap. Does it look right?

    calculated at:
    29% lye concentration
    -2% SF
    Tetra EDTA 0.5% of total batch weight dissolved in water blended into fats.

    coconut oil 500g
    distilled water 228.7g
    NaOH 93.4g
    837.1g total batch x 0.005= 4.1g EDTA dissolved in <10g water (to make it 29-30% lye conc)

    Thank you in advance for any help! If this is too late to be posting on this thread, I apologize and will be happy to start a new thread!
     
  10. Jul 11, 2019 #10

    DeeAnna

    DeeAnna

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    My answer in Post 4 is about citrate, but it also applies to EDTA. The math will look different for EDTA, but the final answer is the same as for citrate. You can't possibly stuff enough EDTA or citrate into your soap to effectively treat the hard water in a clothes washer full of water. Even if it's a high-efficiency washing machine, that's still far too much water to treat just with a chelator added to your soap.

    It won't hurt to use a chelator (citrate or EDTA) but it's not the answer for laundry soap or dishwashing soap. You have to soften water with a whole-house softener or add a separate softening agent like washing soda (or you can do both, as I do) if you want to treat all of the water for a load of laundry or for washing dishes in a sink full of water. Chelator or no chelator, you should still use a 1 to 1 ratio of soap to washing soda or follow Szaza's recommendations, whichever seems best for your situation.

    From Post 4: "...A chelator like citrate (citric acid + NaOH) or EDTA is pretty effective at treating small amounts of water hardness ... like the water on your washcloth when you bathe. When you wash clothes (or dishes in a sink full of water), there is a lot more hard water minerals for the chelator to treat and that becomes difficult if not impossible...."
     
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