# Lye--how long can it sit?



## Bibba (Aug 14, 2010)

Hi all, I have been making CP for about 12 years but am stumped on something...

How long can lye sit after the mixing before making the soap? I was all set last weekend to make a batch, was almost done measuring everything when I discovered I was out of palm (main ingrediant in this receipe). It took a few days to get it in. So, the lye mixture has been sitting for just over a week. Can I still use it today for a batch or should I start over. If I start over, how do I safely get rid of the spoiled lye mixture?

Thanks for your help!


----------



## NancyRogers (Aug 14, 2010)

I know that some people here do a premixed 50% lye solution that they keep stored.  I don't know what your concentration was, but to answer your question, I would bet that you need to let us know that information and if you kept your solution covered.

Maybe someone with more experience in this area will chime in.


----------



## tespring (Aug 14, 2010)

I mix my lye/water mixture up in advance and so far, I have left it two to three weeks and this was after accidently freezing it.


----------



## Deda (Aug 14, 2010)

It will keep a long time, not sure exactly how long, but weeks at least.

However, it must be stored in an air tight container.  If left open the water will evaporate, leaving you with a solution with less than 50% water.


----------



## Bibba (Aug 14, 2010)

Thanks for the help...it was open, so I think I am going to start over...oils are more expensive than lye.


----------



## Deda (Aug 14, 2010)

If you know EXACTLY how much it should weigh, Lye + Water + Container then you can add the missing water.


----------



## IrishLass (Aug 14, 2010)

I masterbatch my lye, and it lasts a _long_ time. We're talking months here. As an experiment, the longest I've let it sit (in my airtight container) has been 3 months. It still soaped just fine. 

IrishLass


----------



## Deda (Aug 14, 2010)

IrishLass, what kind of container do you use?  I'm using an empty laundry detergent bottle, it's about 2 gallons.  I love to find something bigger, still airtight that could hold more than a week or 10 days worth of lye.  Batching the lye is seriously my worst soaping task.


----------



## IrishLass (Aug 15, 2010)

I use empty laundry detergent bottles, too. All detergent to be exact, with the drip-proof spout and tight screw-on lid. I am currently using two of them. They hold 100 fluid ounces each. I wish I could be of more help, but it sounds like yours are already a bit larger than mine. 

IrishLass


----------



## MagiaDellaLuna (Aug 15, 2010)

Deda said:
			
		

> Batching the lye is seriously my worst soaping task.



I feel your pain. I hate batching the lye with a passion.

PS !!!  I use the large (25 Kg, 55 lb.) very thick bucket with a VERY tight fitting lid in which my Lye is supplied.


----------



## Deda (Aug 15, 2010)

IrishLass said:
			
		

> I use empty laundry detergent bottles, too. All detergent to be exact, with the drip-proof spout and tight screw-on lid. I am currently using two of them. They hold 100 fluid ounces each. I wish I could be of more help, but it sounds like yours are already a bit larger than mine.
> 
> IrishLass



Duh, I could use 2 bottles!  Why is it when the most obvious solution is right in front of me I usually just step right over it?



			
				MagiaDellaLuna said:
			
		

> PS !!!  I use the large (25 Kg, 55 lb.) very thick bucket with a VERY tight fitting lid in which my Lye is supplied.



No such luck, my lye comes in bags, similar to grass seed or mulch.


----------



## Bibba (Aug 15, 2010)

Great suggestions all. With a duplicate bucket, I have figured out the exact weight as suggested, then replaced the missing 75kg of water. We'll see how it goes.

From now on, I think I will mix lye ahead of time and store it in laundry jugs. Seems like this will be more efficient.


----------



## jewelz (Feb 5, 2020)

IrishLass said:


> I masterbatch my lye, and it lasts a _long_ time. We're talking months here. As an experiment, the longest I've let it sit (in my airtight container) has been 3 months. It still soaped just fine.
> 
> IrishLass



IrishLass,

Would you have to heat your lye mixture to add to your oil mixture then?


----------



## DeeAnna (Feb 5, 2020)

Not Irish Lass, but I use masterbatched lye too, so think I'm qualified to answer. 

You don't have to heat the lye solution before use. 

In fact, for safety reasons, I strongly advise against heating lye solution for any reason. If you need higher temps, heat the fats, not the lye. It's simply safer in case of an accident.


----------



## jewelz (Feb 5, 2020)

Thank you DeeAnna!
I mixed it as you suggested and it worked like a charm!


----------



## IrishLass (Feb 6, 2020)

Late to the party, but ditto what DeeAnna said. I used to warm my masterbatch lye solution in a hot water bath (in my sink, not on the stove), which worked fine for me, but it is easier just to heat the fats warmer.


IrishLass


----------



## Mistrael (Feb 7, 2020)

I've been thinking of trying to masterbatch my lye to make life easier, so thanks for all the info! I'd been wondering how long it could sit too.


----------



## Todd Ziegler (Feb 7, 2020)

IrishLass said:


> I masterbatch my lye, and it lasts a _long_ time. We're talking months here. As an experiment, the longest I've let it sit (in my airtight container) has been 3 months. It still soaped just fine.
> 
> IrishLass


Would you mind telling me what you do to make your master batch of lye. I have some 2 gallon chemical containers that I got from a fertilizer company (brand new never been used) and I think it would be worth making some ahead of time. I think I know what to do but confirmation would be better. Also I have an RO filter with a deionizer filter, would that make the water better or would it be ok with just running the water through the RO filter and bypassing the DI filter?


----------



## jcandleattic (Feb 7, 2020)

Todd Ziegler said:


> Would you mind telling me what you do to make your master batch of lye. I have some 2 gallon chemical containers that I got from a fertilizer company (brand new never been used) and I think it would be worth making some ahead of time. I think I know what to do but confirmation would be better. Also I have an RO filter with a deionizer filter, would that make the water better or would it be ok with just running the water through the RO filter and bypassing the DI filter?


Not IL either but I mix my lye in a 50/50 solution. I do pretty big batches, and use 12lbs water, and 12lbs lye at a time. mix it slowly in a 3 gallon bucket (which is the perfect fit for this much) 
Because it heats up so much with that much, I then lightly cover it with saran and then the lid (so as it's cooling and some of the water evaporates, it will cling to the wrap and drip back into the solution)
Once it's completely cooled (next day or so) I then ladle it out into my containers, which is 2-3 very well cleaned out laundry jugs. The ones with the screw top and pour spout. Close them tightly, if the 'caution lye' and cross bones markings I put on them has rubbed off, I re mark it, and put them in my storage cupboard. 
If I had little kids here or other people who are allowed in my lab, the cupboard would have a lock, but my granddaughter is 10 and doesn't go down in the basement (which is locked unless I'm home and working down there) 

Hope this helps. You can do the same with smaller than 12lbs each, this is just what is convenient for me. This way I only have to MB lye maybe 2-3 times a year. And yeah, stored tightly sealed, it can last months, years. 
Biggest concern is evaporation, and all that will do is make it a stronger concentration if it does happen. 
At time of soaping I take my 50/50 batch and add the extra liquid at that time to bring it to the concentration I want to soap with. This also makes it convenient to do the split method for milk and another alternative liquids in soap.


----------



## jcandleattic (Feb 7, 2020)

Todd Ziegler said:


> Also I have an RO filter with a deionizer filter, would that make the water better or would it be ok with just running the water through the RO filter and bypassing the DI filter?


Completely missed this portion. I have a RO filter that doesn't offer the DI filter with it and this is the water I use to make my MB lye, and I have never, ever had a problem with the water. (other things yes, but not the RO water!  )


----------



## cmzaha (Feb 7, 2020)

I do mine a bit differently. I mix mine in a 2-gallon HDPE bucket in the sink which is sitting in ice water because it does heat up considerably. While it is cooling I lightly cover with a cloth. At times I will get some lye that settles out of solution which I am sure is from evaporation but it has never affected my soap, and I just prefer to not put a lid on hot lye. I also like to mix in no larger than 2-gallon buckets that I can handle pouring out of into a Rubbermaid pitcher to transfer into my 1-gallon storage bottles. This is all done in my sink in case of spills.


----------



## Todd Ziegler (Feb 7, 2020)

jcandleattic said:


> Completely missed this portion. I have a RO filter that doesn't offer the DI filter with it and this is the water I use to make my MB lye, and I have never, ever had a problem with the water. (other things yes, but not the RO water!  )


That is great because DI filters (good ones) are expensive. I used it for breeding fish. My jugs are what they call splash proof. Kind of like detergent jugs. I knew things could be made easier and now I can eliminate the prep time for the lye. I either use 30% or 33% most of the time, so I have enough jugs.



cmzaha said:


> I do mine a bit differently. I mix mine in a 2-gallon HDPE bucket in the sink which is sitting in ice water because it does heat up considerably. While it is cooling I lightly cover with a cloth. At times I will get some lye that settles out of solution which I am sure is from evaporation but it has never affected my soap, and I just prefer to not put a lid on hot lye. I also like to mix in no larger than 2-gallon buckets that I can handle pouring out of into a Rubbermaid pitcher to transfer into my 1-gallon storage bottles. This is all done in my sink in case of spills.


I have a couple of oil recipes that I like and I am going to make a gallon of the two for use later. I have a old refrigerator in the garage that I can use to store the oils.


----------



## jcandleattic (Feb 7, 2020)

Todd Ziegler said:


> That is great because DI filters (good ones) are expensive. I used it for breeding fish. My jugs are what they call splash proof. Kind of like detergent jugs. I knew things could be made easier and now I can eliminate the prep time for the lye. I either use 30% or 33% most of the time, so I have enough jugs.


If you make the solution in a 50/50 then you can make it to whatever concentration you want at time of soaping. I don't always use the same concentration depending on the soap I'm making so this makes it easier. 



cmzaha said:


> I just prefer to not put a lid on hot lye


My lid and wrap is just loosely set on top of it. I've done this for years now and have never had a problem. I wouldn't be comfortable securing the lid tightly on hot lye either. 



cmzaha said:


> This is all done in my sink in case of spills.


This is also how I do mine, but I don't try to pick it up and pour it. I use a ladle and funnel to get it into the jugs, until I can lift it and then pour it into the funneled container. I make/hold in one side of the sink, then when transferring, have the detergent jug in the other side of the sink.


----------



## IrishLass (Feb 7, 2020)

Todd Ziegler said:


> Would you mind telling me what you do to make your master batch of lye. I have some 2 gallon chemical containers that I got from a fertilizer company (brand new never been used) and I think it would be worth making some ahead of time. I think I know what to do but confirmation would be better. Also I have an RO filter with a deionizer filter, would that make the water better or would it be ok with just running the water through the RO filter and bypassing the DI filter?




I make my 50% lye solution in a plastic PP #5 pitcher with lid, and when it has cooled down I store it in an airtight HDPE container which happenes to be a cleaned-out, reclaimed laundry detergent bottle with a no-drip spout and screwtop lid. As long as it is stored in a proper container and tightly covered, it lasts for a very long time. I'm talking much more than just months, but years. 

The reason I like working from a 50% solution is because it's super easy to figure out the math that it takes to tailor it to use with _any_ recipe no matter how big or small the batch, and no matter what % lye solution you choose to employ for your batch. To tailor it to whatever lye solution I choose to use, I just use this simple 2-part equation, which works across the board with every formula no matter what:

Here's how much 50% lye solution to weigh out for your batch: Multiply the total recipe amount of dry lye your formula calls for by 2. That will give you how much of the 50% lye solution you need to weigh out for your batch.

Here's how much extra water to weigh out for your batch: Subtract the total  recipe amount of dry lye for your formula from the total recipe amount of liquid for your formula. That will give you how much more liquid you need to weigh out for your batch to compensate.

That's all it takes to figure it out. Easy-peasy. 

Now, I do need to make mention that there is some slight evaporation that takes place when mixing the 50% solution. After my very first master-batch in which I made sure to weigh everything from beginning to end (container/cover and all), I figured out that my water loss from the heat reaction during mixing came to 6 grams worth, i.e., it weighed 6 grams less than it should have, so I just added 6 grams of water back in to compensate and all went well.

The size of my 50/50 masterbatch is a little over 4 lbs. worth, so as a result of my first experience, after having first weighed out my container and cover, I now weigh out 2 lbs 3.3 oz (or 1002 grams) of lye. And then I weigh out 2 lbs 3.6 oz (or 1008 grams) of water- a 6 grams excess. In the end, right when I get done mixing, I weigh my finished solution to see if it all adds up correctly (the weight should be 2004 grams if all went well). If it comes up short (which surprisingly has never happened yet with my subsequent masterbatches), I would just add more water at this time to equal 2004 grams, but so far, all has gone well and it weighs out 2004 grams - an even 1:1 ratio. When I go to weigh the solution later, after it has cooled off, it's still 2004 grams (I cover my container as soon as I'm done mixing).


IrishLass


----------



## cmzaha (Feb 7, 2020)

I know IL weighs hers and adds in the extra water loss from evaporation but I do not because I am not comfortable with trying to weigh a 2 gallon bucket filled with lye solution.


----------



## Clare7 (Feb 10, 2020)

I use some of my lye when my outside drain gets clogged with shower hair ( sorry that’s gross, I do try to stop it from getting in there!) and then rinse it through well after it’s sat for a while. Eats right through it, so guess you could do that as long as you know no kids/pets/anyone will go near it while it’s sitting. It’ll saponify any fats lurking down there and help break down the fat burgs! I just make sure it’s well washed through and the kitty is locked in


----------



## RDak (Feb 13, 2020)

Deda said:


> IrishLass, what kind of container do you use?  I'm using an empty laundry detergent bottle, it's about 2 gallons.  I love to find something bigger, still airtight that could hold more than a week or 10 days worth of lye.  Batching the lye is seriously my worst soaping task.


Here's one you might like.........

https://www.amazon.com/5-Gallon-Pla...APCYHDNJ6VZ&psc=1&refRID=WHEPXX25BAPCYHDNJ6VZ


----------



## shunt2011 (Feb 13, 2020)

RDak said:


> Here's one you might like.........
> 
> https://www.amazon.com/5-Gallon-Pla...APCYHDNJ6VZ&psc=1&refRID=WHEPXX25BAPCYHDNJ6VZ


Deda hasn't posted here since 2012


----------



## GML (Feb 13, 2020)

Perhaps the users who haven't posted in years can have their names removed so that they're not being quoted and it will save time from you having to post when they last posted?


----------



## Claudette Carignan (Feb 14, 2020)

IrishLass said:


> I make my 50% lye solution in a plastic PP #5 pitcher with lid, and when it has cooled down I store it in an airtight HDPE container which happenes to be a cleaned-out, reclaimed laundry detergent bottle with a no-drip spout and screwtop lid. As long as it is stored in a proper container and tightly covered, it lasts for a very long time. I'm talking much more than just months, but years.
> 
> The reason I like working from a 50% solution is because it's super easy to figure out the math that it takes to tailor it to use with _any_ recipe no matter how big or small the batch, and no matter what % lye solution you choose to employ for your batch. To tailor it to whatever lye solution I choose to use, I just use this simple 2-part equation, which works across the board with every formula no matter what:
> 
> ...



Would a jerry can (brand new) be equally suitable to use? The reason I’m asking is ravise I have Issues with my left arm and can not lift a container that heavy. The jerry cans come in all sizes.


----------



## IrishLass (Feb 14, 2020)

Claudette Carignan said:


> Would a jerry can (brand new) be equally suitable to use? The reason I’m asking is ravise I have Issues with my left arm and can not lift a container that heavy. The jerry cans come in all sizes.




Hi Claudette! As long as the jerry can is made of HDPE plastic (and it looks like they are), you'll be fine!



IrishLass


----------



## Claudette Carignan (Feb 14, 2020)

IrishLass said:


> Hi Claudette! As long as the jerry can is made of HDPE plastic (and it looks like they are), you'll be fine!
> 
> 
> 
> IrishLass


Thank you!


----------



## Suz (Feb 15, 2020)

Do those of you who use premixed 50:50 lye solution, heat it up a bit when soaping so it’s not too cold?


----------



## DeeAnna (Feb 15, 2020)

I use 50% NaOH solution at room temperature. If I want the soap batter to be warmer, I heat the fats rather than the lye solution for safety's sake.

If you've been taught the myth that the temps of the lye solution and fats must be within 10 degrees, you can toss that out the window. It's the batter temp that's important for the outcome of your soap making.

It's certainly easy to understand if the lye solution and the fats are about the same temp, say 100 F, then the soap batter will be about 100 F as well. But that's the only advantage to matching the temps of the lye and fat.

As far as the chemistry is concerned, your lye solution could be 70F and your fats could be 110F, but if the soap batter is 100F when the two parts are mixed, that's the only temp that really matters.

The only caveat about the temperature of a masterbatched 50% lye solution -- This solution must be kept above 60F / 20C while in storage. If the solution cools into the middle 50s F, some of the NaOH will crystallize out and form a glass-like sheet of solid NaOH on the bottom of the container.

You must get the solid NaOH fully dissolved before the solution can be used, which takes a fair bit of work and patience. It is _much _easier to avoid the problem than to have to fix it.


----------



## Amy Robinson (Feb 15, 2020)

I gave it a try as I think it could save quite abit of time.  I left my usual quantity lye solution out overnight.  In the morning it was a little gloopy which I didn't expect. Can anyone tell me if this is normal please.


----------



## DeeAnna (Feb 15, 2020)

I have no idea how to answer your question without any real details. 

What was the lye concentration? Was the solution in a container that was open to the air or was it in a closed container? What temperature was the lye solution while it sat overnight? What do you mean by gloopy -- can you explain in concrete words what you are seeing?


----------



## BubblingBrooke (Jan 20, 2021)

I know it's a bit late, but I've had my lye solution dip to 70 F before - going by the myth that everything needed to be within 10 degrees of each other - I would re warm my lye water solution and oils. I have an old sock full of rice that I microwave and sandwich between my container of oils and container of lye solution. Brings it up to about our just under 80 F. I probably won't do that any longer, but it seemed like a much safer way to warm it back up - I read about others putting it in a microwave and that freaked me out!!


----------



## TheGecko (Jan 21, 2021)

I master batch...33% Lye Solution.  I make not quite 2 gallons at a time and then store it in the back of my soap cart.  Since I master batch my oils/butters too (640 oz in a 5-gal bucket), I just reheat my oil (after a good stir with a commercial paint stirrer) 20-40 second PPP and then add my Lye Solution out of the jug.  The Lye Solution temp is cool, but not cold.


----------



## Sudds (Jan 21, 2021)

You folks are awesome! I just posted on what containers should I use to hold my lye solution and here is the answer Except, would empty cleaned out bleach bottles work as well? (I make my own powdered detergent) I also have a RO filter and that also answered my question I hadn't even asked yet! Thank you so much!


----------

