Is there a way to test lye to see if it is still good?

[user 57692]

Is there a way to test lye to see if its still good?

I found out yesterday that a friend has a pail and a small bucket of it in her basement, and said I could have it. The one had a sealed lid, the other one was not a tight seal, but had something heavy on it to keep from opening. She thinks it may have been there for maybe 4-5 years.

One was rock hard, but a bang of the bucket loose some of it up.

 

[lsg]

The best way I know is to try it in a small batch of soap, using cheaper oils.

 

[TheGecko]

I would not use the 'rock hard' one. Odds are good you have a bucket of sodium carbonate instead of sodium hydroxide from the NaOH absorbing water.

 

[Misschief]

When I started out making soap, I was given an old tub of lye by my mom. It was probably 4-5 years old, no more than about 500-600 grams and had been stored in a dry basement. It soaped just fine.

 

[DeeAnna]

Dry NaOH doesn't degrade just because time passes -- it degrades when it is exposed to the moisture and carbon dioxide in the open air. Stored properly in an airtight container, dry NaOH should stay good for years.

If the particles are still loose and flow freely, the NaOH has not been exposed to open air much if at all. It is very likely about as pure as it was when first bought.

If there are clumps of the alkali surrounded by loose particles and the clumps break apart fairly easily, the NaOH is probably good. It may be somewhat less pure but still fine for soap making.

A rough check of purity is to make a solution of 50% dry NaOH and 50% room temperature water. Make about as much of this 50% mixture as you would need to make a typical batch of soap. Immediately after mixing the two and getting the dry alkali dissolved, measure the temperature. It should be 180 F / 82 C and preferably higher. More: NaOH or KOH purity check | Soapy Stuff

If the particles of alkali have mostly fused into hard clumps that cannot be broken apart easily, that's not a good sign. You'd have to dissolve the alkali in water and test the purity of the solution to know what you've got. If I had NaOH that was like this, I'd probably dispose of it safely, rather than try to use it to make soap.

 

[user 57692]

Thanks, appreicate all the feedback.

 

[TheGecko]

If the particles of alkali have mostly fused into hard clumps that cannot be broken apart easily, that's not a good sign. You'd have to dissolve the alkali in water and test the purity of the solution to know what you've got. If I had NaOH that was like this, I'd probably dispose of it safely, rather than try to use it to make soap.

Yeah...don't do what I did and try to run you Sodium Hydroxide through a mesh strainer to filter out the large lumps because I was trying to be 'cost effective' and only removed the hard lumps. Instead I created an electrostatic nightmare and no, I wasn't wearing gloves and I was barefoot and yes, I paid the price for my gross stupidity. I ended up with several chemical burns on my hands and feet that took weeks to heal and I had to do a massive clean-up in my kitchen...wiping down all the counters, the walls, the floor, everything that was sitting out at the time of my extreme foolishness.

 

[user 57692]

What is "electrostatic" ?

Instead I created an electrostatic nightmare

I understand the caution to take when handing lye, the gloves, long sleeves, face shield, as it can dissolve skin. But I have never heard of electrostatic before.

 

[DeeAnna]

I want to also

What is "electrostatic" ?

Have you ever gotten a shock in dry weather when you touch a door knob? Your body has a slight electrical charge that is discharged when you touch the metal. The result is an electrostatic shock, aka a static shock, to your fingertip.

Have you ever seen someone rub a balloon on their hair and then gently touch the balloon to their hair so it sticks in place? That's caused by an electrostatic charge difference between the balloon and the person's hair.

Dry alkali (NaOH) is often sold in the form of small beads (1-2 mm across). These beads develop an electrostatic charge when poured out of a container that is an electrical insulator (typically a plastic jug). This electrostatic charge will cause the small alkali beads to fly in unexpected directions when the air humidity is low (dry) so the static charge is not neutralized. When the humidity is higher, this problem disappears.

If your alkali is in flakes or larger beads, you may not see this problem.

 

[user 57692]

Wow. Yes I understand the balloon on the hair. Thank you for the explanation.