Discussion in 'Lye-Based Soap Forum' started by Fata Morgana, Sep 6, 2014.
When making brine soap, what do you dissolve first in water: salt or NaOH?
I dissolve my salt first but I'm sure you will get answers on both sides.
I also do salt first - whatever little grains of salt which were being tricky dissolving were helped out by the warming of the lye when I added it after.
I haven't done this, to be upfront about my qualifications, but what I'm seeing is to make the salt solution first, then add the lye. The other way 'round doesn't work as well -- the salt doesn't dissolve well in lye solution.
The tricky part is pronunciation, "soul-lay-say-ef-aye"
Actually, when there are an e and an I together in German it is almost always the last that is pronounced.
So ei is sounded as I and ie as e.
So it is actually pronounced
So le si (si as in short for Simon) feh
That aside, I find it intriguing that the lye dissolves in salt water better than the salt dissolves in lye water. I think there was another topic on it where the science was covered but I can't find it I'm afraid
i warm my water then dissolve the salt in the water. I then put my pitcher in the freezer to cool down the salt solution before adding the lye. I always had problems getting it to fully dissolve until I started heating up the water. Not sure if it really makes a difference it just did for me. Made 2 batches of soleseife this week. It has become my hubby's favorite type of soap
Yep, Gent, there was. I think the point is that salt (NaCl) is actually less soluble in water than sodium hydroxide (NaOH). If I recall correctly, a saltwater solution becomes saturated at 26% at room temp. NaOH and water can go up to a 50% solution concentration (actually a wee bit over, but who's counting).
Ah, I knew it was along the lines of saturation, but wasn't sure which was the way it went. Thanks, DeeAnna - you superhero
Thank you for your answers! I’d like to tell you about my little experiment.
I have 3 kinds of salt: Windsor Table salt, Aurora Mediterranean Fine Sea Salt, and Sifto Coarse Salt (no additives):
I poured 16 grams of warm distilled water into 3 separate glasses and added 4 grams (25%) of salt into each of them. I had no problems with dissolving any kind of salt, although the 1st solution with Windsor salt remained slightly cloudy.
1) Windsor Table salt, 2) Aurora Sea Salt, 3) Sifto Coarse Salt
Then I added 5.6 grams of NaOH into each glass and mixed them very well. Each solution looked milky.
I kept mixing them for 30 minutes… but when every time I stop each solution looks like this:
So my questions are:
- what is this sediment?
- can I use a solution that looks like this for making soap? If yes, how can I be sure that all lye is completely dissolved?
- what can I do differently to get a more-or-less clear solution with no sediments?
I had a solution that looked like that and the batch I used it in turned out fine. I have a theory that it is undisolved salt particles (deeanna, feel free to prove me wrong). I only had it happen when I used 2 tablespoons of salt for a 2 pound batch. Now that I use 2 tsp for a 36 Oz batch I no longer have that problem. So perhaps it has something to do with the saturation??
Also check the ingredients - some salts have iodine or anti-caking ingredients.
Here is my math for calculating max salt to use.
In making Soleseife, the Salt is first dissolved into 32.5 oz water before adding the lye.
amount of oils in batch = 100 oz wt
amount of Lye = 13.4 oz wt
amount of Water = 32.5 oz wt
Calculate minimum amount of water needed to dissolve lye = 13.4 * .77 = 10.3 oz
Remaining water available to dissolve salt = 32.5 - 10.3 = 22.2 oz wt water
amount of salt 22.2 oz wt water will dissolve 22.2 x .36 = 8 oz wt salt
A Solubility Table was used. I admit it may not very accurate, but good enough! I think it is useful to keep percentage of salt to lye uniform across various soap recipes.
DO NOT try to dissolve 13.4 oz lye into 10.3 oz water!
I wrote on the 1st page about the salts I used for the experiment, two of them have no additives.
less water than lye? not even 50/50?
"... I have a theory that it is undisolved salt particles (deeanna, feel free to prove me wrong)...."
I'm not absolutely positive on this issue, but that's really the only thing it can be -- undissolved salt. Remember -- we're not dealing with the solubility of salt in plain water. Once the NaOH is added into the mix, the solubility of these chemicals becomes more complicated.
From what I recall, the people who are using brine this concentrated to make brine soap are just using the NaOH-NaCl-water solution as a milky liquid. Or they are going to using less salt to get a clear solution, as hmlove is doing.
Regarding Roy's last post:
The solubility table that Roy references shows how many grams of solute (solute means the chemical that is being dissolved, such as salt, NaOH, etc) per 100 g of solvent (the solvent is what is doing the dissolving -- water in this case). The amount of solute dissolved by a given amount of solvent is one way to talk about solutions of chemicals, but it is not the only common way.
Chemists and soapers can also talk about solubility in terms of solution concentration. If we soap with a 33% lye solution concentration, that is a mixture of 1 part NaOH and 2 parts water. When the NaOH and water are mixed together 1/3 of the final solution is NaOH. The other 2/3 is water.
Salt solutions can be described in terms of solution concentration too. Using Roy's reference, we know that 36 g of salt can be dissolved by 100 g of water. What is the finished solution concentration? Well the total solution weighs a total of 36 g of salt + 100 g of water = 136 grams total. The percent of salt in this SOLUTION is this: 36 g salt / 136 g solution * 100% = 26% solution concentration. That means about 1/4 of the finished solution is salt and the other 3/4 is water.
Remember I said earlier in this thread that a saturated salt solution is about 26% by weight? I was expressing the same information as Roy, but just in terms of salt concentration, not in terms of g solute / g solvent as in Roy's table.
It gets confusing, hey?
For those who are feeling intimidated by the math, just be careful and ask your local science geek for help if you're not sure.
"...Calculate minimum amount of water needed to dissolve lye = 13.4 * .77 = 10.3 oz ..."
Moving on, I am befuzzled about the number 0.77 in this calculation. Even the referenced solubility table doesn't support the use of that value. ???
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