Filmy lye water: is it safe?

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LisaBoBisa

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I see some soapmakers strain their lye water when they add it to soap oils on YouTube, just to make sure they don't accidentally add an undissolved grain of lye to their soap. I like to add citric acid (and 6.24g extra lye for each 10g citric acid) to my water, and now that I'm trying to make more CP instead of HP, I'm using a lot less water. Plus I sub stuff, sometimes separately, as part of my water (beer! carrot puree! aloe! flaxseed jelly! various types of milk!).

My lye solution starts to get a film on top/solidifies on the sides of the pitcher/gets super cloudy, especially if I cool it below 120F. (And forget trying to dissolve sugar in this!!!) If I scrape the sides of the pitcher to get everything into my soap batter, will I risk burning someone with a bit of undissolved lye? I don't want to lose some of the lye I so carefully measured, bc that'll increase my superfat, but safety...

Does citric acid/citrate/salt and baking soda precipitate out before the lye does, since lye's super soluble? Should I factor the extra lye into my lye:water ratio? Should I add extra water for the citric acid, too? And maybe I should dissolve the sugar in its own water? So many things to learn with CP!
 
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My lye solution starts to get a film on top/solidifies on the sides of the pitcher/gets super cloudy, especially if I cool it below 120F. (And forget trying to dissolve sugar in this!!!) If I scrape the sides of the pitcher to get everything into my soap batter, will I risk burning someone with a bit of undissolved lye? I don't want to lose some of the lye I so carefully measured, bc that'll increase my superfat, but safety...
You should always dissolve any dissolvable additives (sugar, citric acid/citrate, etc.) before adding NaOH to your liquid. You can do that either by separating out some liquid just for dissolving additives, or by dissolving the additives in the entire batch liquid before adding the lye. Trying to add them after adding NaOH can make the additives difficult to dissolve, as you noted.

Remember that any undissolved grains of NaOH aren't going to combine with the fats to make soap. Thus, you end up with a tiny bit more superfat (probably negligible) whether you strain or don't strain. And by not straining, you do risk burning someone's skin with those undissolved grains.

Honestly, I am not as worried about possible grains as I am with possible chunks. That's why I do strain my lye most of the time, but either way, I watch my lye solution as I pour it in, to ensure that no grains or chunks make it into my soap batter.
 
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I see some soapmakers strain their lye water when they add it to soap oils on YouTube, just to make sure they don't accidentally add an undissolved grain of lye to their soap. I like to add citric acid (and 6.24g extra lye for each 10g citric acid) to my water, and now that I'm trying to make more CP instead of HP, I'm using a lot less water. Plus I sub stuff, sometimes separately, as part of my water (beer! carrot puree! aloe! flaxseed jelly! various types of milk!).

My lye solution starts to get a film on top/solidifies on the sides of the pitcher/gets super cloudy, especially if I cool it below 120F. (And forget trying to dissolve sugar in this!!!) If I scrape the sides of the pitcher to get everything into my soap batter, will I risk burning someone with a bit of undissolved lye? I don't want to lose some of the lye I so carefully measured, bc that'll increase my superfat, but safety...

Does citric acid/citrate/salt and baking soda precipitate out before the lye does, since lye's super soluble? Should I factor the extra lye into my lye:water ratio? Should I add extra water for the citric acid, too? And maybe I should dissolve the sugar in its own water? So many things to learn with CP!
I would highly recommend pouring off some of your required liquid for dissolving your additives and using at least 50%, being the minimum amount of liquid for dissolving lye, of your water requirement for dissolving your lye. I simply do not like adding additives to my lye water but I never use sodium lactate that I know folks add to their lye water. Salt and Sugar Will Not dissolve in lye solution but will form hard crystals in the bottom of your container. I simply never dissolve anything other than silk in my lye water because silk will not dissolve in anything other than hot lye solution.

The film you are seeing is most likely soda ash, known as sodium carbonate, which forms from the carbon dioxide in the air reacting with the lye in your lye solution. This does not hurt your soap batter and is not active lye but you can strain it off if it makes you uncomfortable, I do not. It is the same as the soda ash that forms on the outside of curing soaps.
 

LisaBoBisa

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You should always dissolve any dissolvable additives (sugar, citric acid/citrate, etc.) before adding NaOH to your liquid. You can do that either by separating out some liquid just for dissolving additives, or by dissolving the additives in the entire batch liquid before adding the lye. Trying to add them after adding NaOH can make the additives difficult to dissolve, as you noted.

Remember that any undissolved grains of NaOH aren't going to combine with the fats to make soap. Thus, you end up with a tiny bit more superfat (probably negligible) whether you strain or don't strain. And by not straining, you do risk burning someone's skin with those undissolved grains.

Honestly, I am not as worried about possible grains as I am with possible chunks. That's why I do strain my lye most of the time, but either way, I watch my lye solution as I pour it in, to ensure that no grains or chunks make it into my soap batter.
Will sugar scorch if I add it before the lye? Looks like SMF folks really got detailed in this thread! It sounds like lye will theoretically be the last thing to precipitate out, since it's the most soluble, and things like salt/baking soda (for ZNC/soleseife) and citrate/citric acid will theoretically precipitate out first, so that SHOULD be what's hardening on the sides of my container, not lye?

Maybe I can find out for sure if any lye is in the stuff that's hardening on the sides of my pitcher by pH testing it when I clean up afterward. (i.e. dissolve the crud left on my lye pitcher in distilled water and use a pH strip) Looks like sodium citrate is pH 7.5-9.0, and citric acid is 3-6, depending on concentration

I would highly recommend pouring off some of your required liquid for dissolving your additives

Then I'll add as little as possible to my lye water now, too--I noticed Tellervo dissolves citric acid in a separate bit of water and adds it directly to her oils. I'll start doing that and adding lactate and diluted sugar directly to my oils now, too. Do you ever use liquids (milk, aloe, etc) other than vinegar?
 
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DeeAnna

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NaOH will not precipitate out on the sides of your container. It is far too reactive to remain NaOH. That crust you're seeing is sodium carbonate, not sodium hydroxide, due to NaOH reacting with CO2 in the air.

Ditto for citric acid in an NaOH solution. NaOH + citric acid = sodium citrate + H20. If you evaporate a dilute solution of citrate to dryness, you won't magically get NaOH and/or citric acid to re-form ... the dry solids will be sodium citrate.
 
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Then I'll add as little as possible to my lye water now, too--I noticed Tellervo dissolves citric acid in a separate bit of water and adds it directly to her oils. I'll start doing that and adding lactate and diluted sugar directly to my oils now, too. Do you ever use liquids (milk, aloe, etc) other than vinegar?
Lye needs a min of 50% water for dilution which is how many of us masterbatch our 50/50 lye solutions.

I very seldom soap with milk or other liquids but if I do soap with milk, I use powdered milk which I stick blend directly into my oils or dissolve in my vinegar. When I make aloe soap I use fresh aloe which is the only time I do not use vinegar or I mix a new batch of lye mixing lye and vinegar together. Aloe juice which can be purchased by the gallon can be used just like water for mixing your lye, but will usually turn a light yellow which I do not find effects the soap batter color.

If I mix my lye in my vinegar I use chilled vinegar and a large container because I find it will heat up quickly. I have never had lye water volcano when mixing with vinegar but any liquid can if it overheats which is why I use a large container and chilled not frozen or slushy vinegar.

Two hints when using vinegar:
1. Do not jump your lye in all at once.
2. If mixing your lye and vinegar together do not let it sit for long or hours because the vinegar will react with the lye and become very thick with little pills of sodium acetate. How long it takes to thicken I find depends on the size of your solution batch. This is why you cannot masterbatch vinegar/lye solutions.
 

LisaBoBisa

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Ditto for citric acid in an NaOH solution. NaOH + citric acid = sodium citrate + H20. If you evaporate a dilute solution of citrate to dryness, you won't magically get NaOH and/or citric acid to re-form ... the dry solids will be sodium citrate.

Is baking soda + citric acid = sodium citrate + CO2 + H2O reversible, since both reactants are weak?
 

DeeAnna

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I'd guess it would be reversible as long as you can provide a source of CO2 to drive the reverse reaction. Without a sufficient concentration of CO2, it's a one way street.
 

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I see some soapmakers strain their lye water when they add it to soap oils on YouTube, just to make sure they don't accidentally add an undissolved grain of lye to their soap.

Actually, they are straining it to get rid of "lye lint". When Sodium Hydroxide is exposed to Carbon Dioxide it turns into Sodium Carbonate. I used to get a bit of it when I'd leaving my Lye Solution to cool on the dryer overnight without covering it. What little I had would get broken up with the stick blender, so I didn't worry about. Of course, when I left it for three days I got a LOT more and rather than trying to recalculate my lye needs I poured it down the drain.

My lye solution starts to get a film on top/solidifies on the sides of the pitcher/gets super cloudy, especially if I cool it below 120F. (And forget trying to dissolve sugar in this!!!) If I scrape the sides of the pitcher to get everything into my soap batter, will I risk burning someone with a bit of undissolved lye? I don't want to lose some of the lye I so carefully measured, bc that'll increase my superfat, but safety...

Does citric acid/citrate/salt and baking soda precipitate out before the lye does, since lye's super soluble? Should I factor the extra lye into my lye:water ratio? Should I add extra water for the citric acid, too? And maybe I should dissolve the sugar in its own water? So many things to learn with CP!

Your Lye Solution, if freshly made and without additives, should be clear once the Sodium Hydroxide has dissolve and cooled. I only add Sodium Lactate to my Lye Solution so I don't if adding something like sugar, salt, citric acid, etc would cause it to be cloudy. Generally speaking, you only get "lye lint" if you leave your Solution exposed to the air for too long or if it is really cold. I Master Batch my Lye Solution these days...ready-to-use. As long as I keep the spout and cap clean and the cap tightly closed...I've had no issues with it even after six months.

If you have white stuff on the outside of your container it means that you are splashing stuff around...or you have a pinhole or tiny crack in your container. Unless you are making your Lye Solution with frozen liquids, it requires little effort or time to fully dissolve. If you have a pinhole or tiny crack, you want to replace the contain IMMEDIATELY! Do NOT pass GO, do NOT collect $200. Then only think worse than having boiling hot Lye Solution all over the place, is if you were using a glass container when it failed.
 

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Lye needs a min of 50% water for dilution which is how many of us masterbatch our 50/50 lye solutions.
I've never understood the appeal of masterbatching lye solns before, but this makes sense. It'd be easy to measure if it's 1:1 water:lye, and if I don't mix anything else into the lye water, that would make it faster. Does it ever start reacting with your glass or plastic container? How long can you safely keep the masterbatched solution around?
 
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I love masterbatching!

Measure and mix once every few months, instead of every batch? Yes please.

Lye solution is always cool and ready to use? Yes please.

A 50-50 MB solution can make any strength solution I need or want? Yes please.

You want a plastic container (or stainless), not glass. Even borosilicate glass can be etched and weakend when exposed for a long time to a highly alkaline solution. Plus, glass can break when dropped or hit. Glass shards + caustic solution? No thanks. I use a repurposed liquid laundry jug with a tight lid and no-drip spout. If your container is well-sealed, your 50-50 MB solution should stay good indefinitely, at 65ºF and above. Cooler than that, and it can begin precipitating out.
 
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I see some soapmakers strain their lye water when they add it to soap oils on YouTube, just to make sure they don't accidentally add an undissolved grain of lye to their soap. I like to add citric acid (and 6.24g extra lye for each 10g citric acid) to my water, and now that I'm trying to make more CP instead of HP, I'm using a lot less water. Plus I sub stuff, sometimes separately, as part of my water (beer! carrot puree! aloe! flaxseed jelly! various types of milk!).

My lye solution starts to get a film on top/solidifies on the sides of the pitcher/gets super cloudy, especially if I cool it below 120F. (And forget trying to dissolve sugar in this!!!) If I scrape the sides of the pitcher to get everything into my soap batter, will I risk burning someone with a bit of undissolved lye? I don't want to lose some of the lye I so carefully measured, bc that'll increase my superfat, but safety...

Does citric acid/citrate/salt and baking soda precipitate out before the lye does, since lye's super soluble? Should I factor the extra lye into my lye:water ratio? Should I add extra water for the citric acid, too? And maybe I should dissolve the sugar in its own water? So many things to learn with CP!
Hi! I made a Sugar Concentrate Solution that I keep in the refrigerator that I add to my Lye Water, along with Citric Acid and Mix until
Dissolved prior to adding my Lye. After adding Lye and dissolving it, I immediately add my Tussah Silk while still quite hot. When cooled, I add Sodium Lactate. I always strain my Lye when adding it to my oils. If I use Coconut Milk Powder, I mix it in my Oils prior to adding my Lye. Otherwise, Salt & Sugars reform in the bottom of Lye making a mess of your Lye Solution. It works for me. Hope this helps! Blessings!
 
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That seems so practical! How long can you keep it?
Hi! I only make enough for It lasts me about a month before it’s gone. I make sure it stays clear. I do Not Master Batch; use ice nor freeze my liquids anymore unless I’m using Milk or Heavy Cream. I use Tussah Silk and need very high temps to dissolve completely! I just Prefer to do individual batches from scratch! I enjoy The Process. It’s my Therapy, so to speak! It gives me the breaks I need because I’m A Disabled Veteran so I can’t work but a short time before pain overtakes me. I rest & Pray, then get back to it! Hope that helps! Blessings!
 
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I use Tussah Silk and need very high temps to dissolve completely!
I add tussah silk whenever I mix up my master-batches. That generates plenty of heat to dissolve it all.

Obviously, it's up to each individual to decide whether master-batching is the right thing for that person's soaping style. I just don't want anyone to think you can't use silk if you are master-batching. :)
 

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I've never understood the appeal of masterbatching lye solns before, but this makes sense. It'd be easy to measure if it's 1:1 water:lye, and if I don't mix anything else into the lye water, that would make it faster. Does it ever start reacting with your glass or plastic container? How long can you safely keep the masterbatched solution around?

The advantage of Master Batching your Lye Solution is that you never have to wait for it to cool. Of course, you could just use frozen Distilled Water cubes, but I also Master Batch my Oils/Butters and this way, I can spend more more making soap as opposed to getting ingredients outs, weighing, putting them back. I MB 40lbs of Oils/Butters...for the hour it takes me to do it (and I'm MBing my Lye Solution at the same time) I save nine hours.

I mix my Lye Solution in the same bowls that I soap with. I do two at a time and let them sit in the sink in cold water covered by a tea towel. I then use a funnel and pour into a 1 gallon HDPE jug and cap tightly. There have times when I haven't made soap or very little and it's sat there for over six months.

I generally recommend that a person given themselves a year before Master Batching to decide on their recipe because you can't change your MB'd Oils/Butters.
 
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I add tussah silk whenever I mix up my master-batches. That generates plenty of heat to dissolve it all.

Obviously, it's up to each individual to decide whether master-batching is the right thing for that person's soaping style. I just don't want anyone to think you can't use silk if you are master-batching. :)
I Apologize if it was implied from my post that you can not MB if you use Tussah Silk! I was speaking for me and what I choose to do bc I have different recipes that may be different Lye Concentrations and Oils and because I enjoy the process. It allows me the Breaks I need, yet feel Productive. I love the process and it works for me! Blessings!
 
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I Apologize if it was implied from my post that you can not MB if you use Tussah Silk! I was speaking for me and what I choose to do bc I have different recipes that may be different Lye Concentrations and Oils and because I enjoy the process. It allows me the Breaks I need, yet feel Productive. I love the process and it works for me! Blessings!
No worries, @SoapLover1 I understand what you meant. I just wanted to be sure that newbies reading the thread would also understand the possibilities for adding tussah silk, as well as creating different lye concentrations from master-batched lye.

The SoapmakingFriend calculator is awesome for that! You can put in your MB lye concentration, and then your final desired concentration, and it gives you the correct amount of both the MB lye solution and the additional liquid. If it weren't for that convenience, I'd probably make my solution each time, too. :)
 
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