Glass and lye; truth or myth?

Soapmaking Forum - Soap & Candle Forums

Help Support Soapmaking Forum - Soap & Candle Forums:

earlene

Grandmother & Soaper
Lifetime Supporter
Joined
Apr 30, 2016
Messages
8,962
Reaction score
10,365
Location
Western Illinois, USA
Personal experience speaks volumes:


Have I had glass break while I was handling it? Yes. I have broken many a glass pitcher, bowl, Mason jars, cups, even a fine crystal bowl, which shattered to smithereens that traveled several feet into two adjacent rooms. Luckily none of those had lye in them, but cleaning up broken glass is not fun and oftentimes not as thorough as one might think. Sometimes shards of glass have shown up in the bottom of a bare foot or toe days later. So the chance that I might break a glass container of lye is too high. (I know myself & do my best to take appropriate precautions.) Perhaps someone else here has never even once dropped or chipped or even bumped a glass container, but that's not me.

Have I had a lye-mixing vessel fail or break with lye solution inside it and leak lye out of the bottom of the vessel onto the surrounding surface? Yes. Luckily it was sitting inside my sink where I mix my lye solution, when this happened. And it was before I realized that not all plastic is lye resistant. It was a cheap, but not PP or HDPE plastic measuring cup and & I had only used it for lye solution mixing maybe 3 to 5 times before the lye solution had deteriorated the bottom of the container enough to make it crack.

Have I ever knocked over a container of lye solution (even when inside of a safe vessel)? Yes, I have. Luckily that has only happened when the vessel was sitting in my sink where I mix my lye and one other time when it was in a tightly sealed HDPE bottle with a cap that has an excellent seal, so there was no leakage. I also was quick to set the bottle upright and checked for leakage just to be sure, then placed it in the sink (it had been on the counter next to the sink when I bumped it & knocked it over.)

Have I ever seen a pyrex measuring cup that looks like the inside has scratches and etching? Yes. I shop at Goodwill & other second hand stores around the country whenever I have a chance and enough free time. I've seen a few Pyrex mixing bowls that had extensive scratches & possible etching on the insides of these glass vessels. True, I don't know exactly how they got scratched up, but it's obvious to me that the glass is so damaged on the inside surface that I wouldn't use that vessel (or vessels) for any purpose because I would not consider these glass containers to be food safe and especially not safe for caustic solutions.

Even if someone wants to dis-believe or deny that lye solution can etch glass, and that eventually said damaged glass may shatter at the most inopportune time, all these other personal experiences tell me that glass is not the safest choice for me when making soap and I certainly would not want my granddaughter making lye solution in glass either.

The only thing I have used glass for during soapmaking,was to measure fragrance, and that has not been often, simply because I prefer lighter weight unbreakable containers when making soap.
 

TheGecko

Well-Known Member
Joined
Jul 22, 2019
Messages
2,107
Reaction score
3,534
Location
Oregon
I remember when Corningware first came out: From the freezer...to the oven...to the table. was a catchy tune in their commercials, except is you look carefully it's all a lie. Almost every piece of bake/cookware that is supposedly coming from the 'freezer' is actually coming out of the refrigerator. Even the 2-second shot that looks like it's coming from the freezer with it's bit of wispy air...who would freeze a dish with the glass top on? And why didn't said glass frost over. When soup pot is placed on the stove, not only is the soup not frozen, it's placed on gas stove with a low flame. And everyone who was placing said bake/cookware on the table, has bare hands. No way you can take a freshly baked dish from the oven (or microwave) without something to protect your hands from burning. And every one of those dishes supposedly straight out of the oven was set directly on table. What the heck?!?

New Pyrex is not the same as old (vintage) Pyrex...it's no longer made with a thermal shock resistant glass; soda-lime instead of borosilicate. One way to tell the difference, especially with the clear baking pans is to look at the name...if it's from Corning, it will say "PYREX", if it's from a licensed company, it will say "pyrex". Newer Pyrex has a different 'feel' to it and it's lighter and thinner.

And another thing, how many people hand-wash their dishes? I don't think we consider just how abusive a dishwasher is to our dishes...the constant pounding of approximately 110F - 170F water through three different 'cycles', the 'dry heat' so we don't have to hand-dry. Take a typical drinking glass...hand wash one, dishwasher wash another and you'll see a huge difference between the two within a year.
 

MellonFriend

Well-Known Member
Joined
Jun 28, 2021
Messages
216
Reaction score
506
Location
Middle Earth or Metropolis
I've never really understood this issue that has been around forever it seems. Specifically, I don't understand why people want to use glass/Pyrex.
Aside from the possibility of breakage, it's far more expensive and cumbersome than using plastic pitchers and bowls/buckets for soapmaking.
Am I missing something?
Well for example I got mine at goodwill where they were only around $3 dollars each and there were way more glass containers than plastic.
 

SirSoapsAlot

Member
Joined
Aug 19, 2021
Messages
9
Reaction score
13
Location
Temecula, CA
I've never really understood this issue that has been around forever it seems. Specifically, I don't understand why people want to use glass/Pyrex.
Aside from the possibility of breakage, it's far more expensive and cumbersome than using plastic pitchers and bowls/buckets for soapmaking.
Am I missing something?
The main reason people want to use glass is chemicals in plastics. I find the plastic stuff is more difficult to get the oil residues off as well. I hand wash and then still run it through the dishwasher.
 

earlene

Grandmother & Soaper
Lifetime Supporter
Joined
Apr 30, 2016
Messages
8,962
Reaction score
10,365
Location
Western Illinois, USA
Personally, I am not concerned with the chemicals in plastic when I am mixing Sodium Hydroxide or Potassium Hydroxide in said plastic. To me the caustic lye is far more worrisome as a chemical than the chemical make-up of Polypropylene (PP - recycle code #2) or High Density Polyethylene (HDPE - recycle code #5). They are both made via thermoplastic polymers made from petroleum. Granted it may not be as preferred within the recycling circuit as glass but there is so much of it around and more often than not, I buy mine used at Goodwill and other second hand stores, so it's getting re-used all the time. (Strangely, I rarely see glass measuring cups and glass jars at second hand stores. Maybe I don't get to the places where @MellonFriend lives, although I have been to Metropolis, IL. - *see thumbnail below)

I might prefer glass Mason Jars for pantry storage (dried beans, dried grains, and whatnot), but they are so heavy when full that I have broken enough of them, so that I have taken to utilizing plastics for pantry storage as well, just to protect my toes and prevent my diminished hand & grip strength from breaking more glass.

I did purchase a SS vessel for making lye solution, but unfortunately it is not lighter than plastic AND it has no lid like my plastic lye containers do, so I have only used it once or twice to make lye solution. Seems a shame, but I really prefer the method I use more making lye solution.

*Thumbnail of SuperHubby in Metropolis:
1632757792406.png
 

MellonFriend

Well-Known Member
Joined
Jun 28, 2021
Messages
216
Reaction score
506
Location
Middle Earth or Metropolis
(Strangely, I rarely see glass measuring cups and glass jars at second hand stores. Maybe I don't get to the places where @MellonFriend lives, although I have been to Metropolis, IL. - *see thumbnail below)
Haha! Your husband is a dead ringer for Superman! 😆

My location is only a reference to my love of Superman (The Middle Earth part is for my Lord of the Rings fandom) I'm actually in NC, so nowhere near Illinois. ☺

I'm going to visit the dollar store to see if I can find me some safer plastic lye vessels.
 

Mistrael

Lifetime Supporter
Joined
Aug 2, 2019
Messages
100
Reaction score
203
Location
Detroit
About 15ish years ago "exploding" glass measuring & baking dishes were in the news. That's all I need to know to be unwilling to trust glass with lye. Theoretically, glass should be fine. In reality, it is only fine until it is not, and there's no reliable warning sign to tell us when it needs to be replaced.

Have I ever had pyrex explode on me? Nope. Do I believe the people who have had that experience? Yup. Am I willing to accept that risk? Nope. And that's what it comes down to, which risks we're willing to take.

When I make soap I am almost always wearing a tank top. My legs and feet are usually bare too - though I'm eying some new chef clogs! It isn't that I'm unaware or in denial about the risks of lye on skin. I understand and accept those risks because lye scalds are no big deal to me but wrecking my clothes would be upsetting.

Now, someone is going to think I'm nuts and that's okay. I do NOT advise anyone to do what I do - UNLESS - they are also a former cook. Once you've been burned by deck ovens and splatter from fryers, or maybe lopped off a piece of a finger...? I'll just say cooks/chefs are a special kind of crazy. 😂 Lye scalds are an irritation to me, but that's about it. I rinse lye off when I'm done soaping. When it's red and itchy later I might remember to rub some shea on it.

To me, lye scald is an acceptable risk but broken glass (and a wrecked batch 😱😱😱) is not. Some people feel differently and that's fine. It's an objective fact that using glass is a risk, just like soaping with bare skin is a risk. It just depends on what we're willing to accept for ourselves.
 

IrishLass

Staff member
Admin
Moderator
Supporting Member
Joined
Feb 11, 2008
Messages
17,494
Reaction score
11,378
Location
Right here, silly!
Oh no, not this subject again. lol We have so may threads and posts on this issue going back years.

In all my research and listening to different experiences of various chemists and those that work in labs who have had their glass lye storage bottles dissolve bit by bit over time from the lye......but more importantly, listening to the many soapers who have had their Pyrex shatter on them when working with lye.... my own stance, as well as the official stance of the Admins here SMF remains the same....soaping with glass is just asking for trouble. I liken it to playing a game of Russian Roulette. You may have nothing happen for several soaping sessions and be lulled that all the warnings must be bunk, but we've had one too many soapers chime in with their experiences that have proven otherwise, and so it's not something we recommend. If anyone wants to do it anyway, that's their own business and they are certainly free to take that risk and do so, but we will continue to warn of the dangers.

Here are some links to just a few of our members have posted in regards to their experiences of having had their Pyrex go kaboom on them when soaping, or in the dishwasher, or just sitting in the sink or cupboard (there are more, but these are enough to suffice):

Forum member BlueberryHill from 2015:
BlueberryHill said:
I just had my Pyrex glass measuring cup explode as I was pouring lye into it! Thank goodness it was in my laundry sink, where I always mix my lye water, and I was all safety geared up! I'm shocked because I used it last week for the first time and it was fine. I thought I was being safer using the Pyrex than the plastic container from the dollar store. I hadn't read the article in this thread before. Beware everyone.
From forum member Raha from 2010:
Raha said:
Dear Soap Makers,
Today I write for your support. I always try to be so careful when dealing with lye--as I have read a few horror stories. Well, I made a big mistake today...while making my green tea soap, I poured hot green tea in with lye...I feel so horrible for making such a big mistake...the lye bubbled up like a volcano and I stepped back and then the whole glass jug exploded. I am so so so grateful that I didn't get hurt (except for a minor burn on my thumb). I just finished cleaning the minimum and plan in a half hour or so to continue the mass clean up.
Anyways, thank you for your support and just let me share my frustrations...
Gratefully yours,
Raha
From forum member Deda from 2010
Deda said:
Earlier this week I had a Pampered Chef glass batter bowl [which is made from tempered glass] explode just sitting, clean, dry and unused on the shelf. I didn't use it for soap, only pancake batter. Can you imagine the havoc wreaked if it had been filled with lye/water.
Forum member Paillo from 2011:
Paillo said:
i would be scared to death to use a glass or pyrex container for my main mixing bowl. i use glass for my smaller containers -- swirl colors, milk mixtures, etc. but last week we had a large pyrex container shatter in the sink. mercifully it wasn't soap, but there were scary sharp shards of glass everywhere, and one of us or one of the pets underfoot could have been seriously hurt.
Forum member Candybee from 2013:
Candybee said:
From my own personal experience I had a large pyrex measuring cup shatter on me one day. I wasn't using it for CP at the time. I had been making M&P soap in that glass for about 5 yrs before it finally broke. I was so surprized and had not imagined that such a sturdy popular brand of glassware would shatter on me but it sure did. So when seasoned soapers tell me that lye can etch the glass that tells me it weakens the glass and yes it will eventually shatter. Could take a few weeks or a few years but I would not want to be there if it shattered with a lye mixture in it.
Forum member Newbie from 2016:
Newbie said:
I am one of the people who has had pyrex shatter. Thankfully, it shattered while in the dishwasher instead of all over my kitchen. Lesson learned.
If the Dish Forum was still around, I could send you a bunch of links to shattered Pyrex experiences during soaping from the members there, too, but unfortunately they are offline.

Anyway, like I've posted before in other threads, glass is pretty strong stuff, but there are four things that are its 'kryptonite (if I can borrow from Superman jargon), i.e., things that aggressively attack it and weaken its resistance, causing it to actually corrode and even dissolve layer by layer:

1) Hydroflouric acid
2) Concentrated phosphoric acic (when hot or when it contains flourides)
3) Hot concentrated alkali solutions of at least 9 pH (lye has a pH of 14)
4) Superheated water

Of the above 4 things, the thing that concerns us as soapmakers of course is #3, alkali. Alkalis affect the surface of glass by directly attacking the silica that the glass is made of, leading to its dissolution, little by little, over time as the surface of the glass is repeatedly exposed to the alkaline solution. And the rate of corrosion increases if the hot alkaline substance is agitated, such as when being stirred.

The above corrosion happens to all glass with the repeated exposure to hot lye solution- even borosilicate. See the following safety sheet on borosilicate glass....scroll down to 3.3 under Chemical Composition:
https://www.scilabware.com/en/glass-types-properties
Here's a quote from that link: "Only hydrofluoric acid, hot concentrated phosphoric acid and strong
alkaline solutions cause appreciable corrosion of the glass." [emphasis mine]


Also this in regards to borosilicate glass: Glass Properties
"Resistance to alkaline solutions is moderate and strong alkaline solutions cause rapid corrosion of the glass, as does Hydrofluoric acid and hot concentrated Phosphoric acid." [emphasis mine]


See also the following in regards to how glass corrodes: Glass corrosion "Glass is resistant to most acids but is highly susceptible to attack by alkaline materials, especially a concentration of OH- ions giving a pH greater than 9.0. The result is an attack of the network forming silica-oxygen (Si-O) bonds, leading to dissolution of the glass surface." [emphasis mine]

While it's true that borosilicate glass is stronger and more resistant and takes a longer time to weaken than soda-lime glass, its still chemically vulnerable to concentrated alkaline solutions and will dissolve bit by bit with every exposure until it reaches the point of no return, aka, 'kaboom!'. The problem is that it's impossible for any of us to know when the shattering day of reckoning will arrive until it actually arrives. You may be willing to take that risk, and that is your choice, but I for one will continue to 'proselytize' about it so that those who are new to the craft and haven't yet been made aware of this issue will at least be able to make an informed choice when deciding what kind of vessels to use to mix lye or in which to soap.


IrishLass :)
 

melonpan

Well-Known Member
Joined
Aug 11, 2020
Messages
71
Reaction score
183
Location
UK
So when I was a noob, I was super careful to follow all the safety precautions including not using glass containers. This was during the time when I was compulsive about the temperatures of my lye solution and oil mix (now I do room temp or "warm to the touch"). I re-purposed my wife's glass candy thermometer and would just leave it in my lye solution. I am embarrassed that my brain understood not to use glass bowls -- but I used a glass thermometer! Yikes-kers. One session, I pulled out the thermometer and it shattered into a thousand pieces in my hand. I was not hurt but just incredibly gobsmacked by my own stupidity!
Yes, I'm typing all of this out loud!! Don't hate on me!!
So, I'll be very honest here and confess that I was the same... it makes me feel slightly better knowing that I'm not the only one!
I stopped using my glass containers for soaping, but somehow I didn't extend the same risk assessment to my candy glass thermometer... Luckily, said candy thermometer decided to take the matter in its hand - it slipped when I was putting it away and it shattered on the ground.
And that's when it dawned on me. Glass thermometer!
 

Zing

Lifetime Supporter
Joined
Apr 5, 2018
Messages
1,849
Reaction score
5,577
Location
Minnesota
So, I'll be very honest here and confess that I was the same... it makes me feel slightly better knowing that I'm not the only one!
I stopped using my glass containers for soaping, but somehow I didn't extend the same risk assessment to my candy glass thermometer... Luckily, said candy thermometer decided to take the matter in its hand - it slipped when I was putting it away and it shattered on the ground.
And that's when it dawned on me. Glass thermometer!
Ryan Reynolds Ugh GIF by 20th Century Fox Home Entertainment
 

earlene

Grandmother & Soaper
Lifetime Supporter
Joined
Apr 30, 2016
Messages
8,962
Reaction score
10,365
Location
Western Illinois, USA
According to The Handcrafted Soap & Cosmetic Guild (HSCG), Heat Resistant Glass is acceptable for mixing Lye.
And that's fine as long as the well-informed user chooses to go that route. I personally know it is not acceptable for ME and will still caution others of the safety issues as regards glass.
 

Rsapienza

Supporting Member
Joined
Dec 24, 2017
Messages
374
Reaction score
625
Location
Florida
I don’t personally understand the debate? Like, why? If you know it’s possible or that numerous people have claimed to have personally experienced it, why in the heck would you risk it??? So strange how different brains work….SMH
 

Professor Bernardo

Supporting Member
Joined
Mar 13, 2021
Messages
181
Reaction score
315
Location
Moved to The Oort Cloud...
Luckily, said candy thermometer decided to take the matter in its hand - it slipped when I was putting it away and it shattered on the ground.
And that's when it dawned on me. Glass thermometer!
Invest in a Laser Infrared thermometer. You can get them for around $18-24 dollars on Amazon, Ebay, Walmart, etc. The only thing I would do extra is put a fresh good top brand battery in it, such a Duracell, Eveready, or Rayovac. The Chi-nee supplied batteries are sketchy at best.

These are much more accurate and safer to use because the thermometer doesn't touch the product at all. They're used extensively in the restaurant industry for checking holding temperatures of food on the line. You can choose between Fahrenheit or Celsius readings, they have a backlight option too. Pistol grip is comfortable for any size hand.

71R0Eoylj8L._AC_SL1500_.jpg
 

Megan

Well-Known Member
Joined
Jul 1, 2018
Messages
791
Reaction score
912
Location
Ohio
I don’t personally understand the debate? Like, why? If you know it’s possible or that numerous people have claimed to have personally experienced it, why in the heck would you risk it??? So strange how different brains work….SMH
Seems like current events would indicate that this is just unfortunately human nature...
 

Cat&Oak

Supporting Member
Joined
May 27, 2021
Messages
385
Reaction score
654
Location
Sparks, Nevada
Invest in a Laser Infrared thermometer. You can get them for around $18-24 dollars on Amazon, Ebay, Walmart, etc. The only thing I would do extra is put a fresh good top brand battery in it, such a Duracell, Eveready, or Rayovac. The Chi-nee supplied batteries are sketchy at best.

These are much more accurate and safer to use because the thermometer doesn't touch the product at all. They're used extensively in the restaurant industry for checking holding temperatures of food on the line. You can choose between Fahrenheit or Celsius readings, they have a backlight option too. Pistol grip is comfortable for any size hand.

View attachment 61306
Same one I use, it's perfect
 

Latest posts

Top