Just curious if sodium citrate can be used as a chelating agent when making liquid soap?
Yes, sodium citrate can be added to liquid soap -- you can add it directly to the water when you make up your lye solution. The typical dosage for hard-water treatment would be about 1.3% sodium citrate based on the oil weight, but the dose could go as high as about 4% sodium citrate. This range of dosages for sodium citrate is equivalent to adding citric acid from 1% to 3% based on oil weight.
Alternatively, you could do what the others are suggesting and just add citric acid to your soap recipe and let it react with the KOH -- you'll want to add extra KOH to compensate for this chemical reaction. By reacting with KOH, you'd be making potassium citrate instead of sodium citrate, but I'm not certain that makes much difference in the overall performance of this additive.
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If dosage rate for citric acid is 1% by weight of oils, the equivalent dosage for sodium citrate is 1.3%
If dosage rate for citric acid is 1% by weight of oils, the equivalent dosage for potassium citrate is 1.6%
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Typical dosage: 10 g citric acid for every 1,000 g oils (1% ppo). Range: 0.1% to 3%. edit: The low end of this range will protect against rancidity (aka DOS); the mid to upper end is to help with hard water scum as well as rancidity.
Citric acid and Sodium hydroxide (NaOH) make Sodium citrate in soap
10 g citric acid neutralizes 6.24 g NaOH, so add an extra 6.24 g of NaOH for every 10 grams of citric added to the recipe.
Citric acid and Potassium hydroxide (KOH) make Potassium citrate in soap
10 g citric acid neutralizes 8.42 g KOH, so add an extra 8.42 g of KOH for every 10 grams of citric added to the recipe.
Stir the citric acid into the water you will use to make your lye solution. Add the lye to the water and proceed with your recipe as usual.
Yes, sodium citrate can be added to liquid soap -- you can add it directly to the water when you make up your lye solution. The typical dosage for hard-water treatment would be about 1.3% sodium citrate based on the oil weight, but the dose could go as high as about 4% sodium citrate. This range of dosages for sodium citrate is equivalent to adding citric acid from 1% to 3% based on oil weight.
Alternatively, you could do what the others are suggesting and just add citric acid to your soap recipe and let it react with the KOH -- you'll want to add extra KOH to compensate for this chemical reaction. By reacting with KOH, you'd be making potassium citrate instead of sodium citrate, but I'm not certain that makes much difference in the overall performance of this additive.
***
If dosage rate for citric acid is 1% by weight of oils, the equivalent dosage for sodium citrate is 1.3%
If dosage rate for citric acid is 1% by weight of oils, the equivalent dosage for potassium citrate is 1.6%
***
Typical dosage: 10 g citric acid for every 1,000 g oils (1% ppo). Range: 0.1% to 3%. edit: The low end of this range will protect against rancidity (aka DOS); the mid to upper end is to help with hard water scum as well as rancidity.
Citric acid and Sodium hydroxide (NaOH) make Sodium citrate in soap
10 g citric acid neutralizes 6.24 g NaOH, so add an extra 6.24 g of NaOH for every 10 grams of citric added to the recipe.
Citric acid and Potassium hydroxide (KOH) make Potassium citrate in soap
10 g citric acid neutralizes 8.42 g KOH, so add an extra 8.42 g of KOH for every 10 grams of citric added to the recipe.
Stir the citric acid into the water you will use to make your lye solution. Add the lye to the water and proceed with your recipe as usual.
I would like to know the method to use citric acid in LS Glycerin method. Because our water is very hard, can I add citric acid 10 grams dissolved in 20 grams water and then add the glycerin to it after subtracting 20 grams of actual glycerin weight?
Many people talk only about sodium citrate for hard water issue. Will the potassium citrate formed by this chemical reaction when KOH is added, as such help overcome hard water issue to some extent?
Yes that worked for me - I asked a similar question here: http://www.soapmakingforum.com/showthread.php?t=58591
That LS turned out nice and clear, just make sure you calculate how much extra lye you will need to compensate
Thanks susie. Adding the sugar mixture to oils means, you mean to say not to add sugar in the water/ glycerin for lye mixture and instead directly add the sugar solution of 20 -25 g to the oils? I was thinking that sugar must be mixed in the water/glycerin meant for lye solution before lye is added and then add that whole mixture to oils. Please clear up my ambiguity.Yes, sugar can be added to liquid or bar soap recipes. Hold out about 20-25 g of water and make it hot water to mix your sugar in (I use 5-10 g sugar/500 g oil), then add the sugar mixture to the oils. Sugar is not an acid, so it does not affect how much NaOH or KOH you use. It makes your lather more bubbly. It does not fix hard water, however.
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