I never liked doing extractions in a milk jug, their opaque and when your trying to dodge an emulsion layer it can be difficult to see where one layer starts and another ends.

I decided to give Ball Mason Jars a try and the 900ml jars are perfect for doing a small 50 gram extraction. These jars worked well for 4 extractions.

On the fifth extraction I was using 50 grams MHRB, 750ml of water, and 50 grams of lye, in each jar. after the first pulls all seemed well, until I picked up a capped jar to let the naptha roll around in the jar. No shaking involved. As I did this I noticed it had pressure cracks, and I had to get it immediately into another container.

I put in a large pyrex vase, I had at my flameworking station. Although the one jar held I can't stress it enough that you don't want to use Ball Mason Jars.

Being a flameworker/glass blower I know a little bit about glass and its behavior when heated or cooled to fast. Pyrex is stable at 1150 degrees this allows you to work on a piece, stick it in the kiln at 1150 then place that glass back in the flame without it cracking.

When pyrex is cooling, (and the temp. drops below 450, depending on thickness, though I wait longer,) it can be taken out of the kiln and left to cool on a graphite plate. Pyrex can withstand extreme thermal reactions, making it the perfect choice for extraction and collection vessels.


Other than clear HDPE jugs what other vessels are safe and easy to use, as far as seeing layers very clearly, for decanting? If some more experienced members can chime in I would greatly appreciate it. Thanks

Until I get a good clear HDPE jug I'll be sticking to pyrex, but would love to hear some other suggestions.

Whats the worry here? that the mason jar might have small cracks from the manufacturing process and or the heat reaction from the lye will crack it?

Mason jars are meant for pressure cookers, which exceeds 250 deg under pressure while rattling around the jars for over a hour.

figures never thought of the canning process, but yeah there were large cracks that would have shattered the whole jar from removing the lid. we did this very carefully and saved all the goods. I also had a jar crack in two when pouring off cold naptha. I just thought it would be wise to let people know about this to prevent any burns/injuries. I'm starting to rethink whether they cracked from lye and its reaction or from pressure. regardless of how it happened if you are using mason jars have some extra containers around just to be careful. just a heads up.

Theyve never done me wrong but if you want to play it absolutely safe, glass will probably break before plastic breaks or ruptures.
I too love glass because i can see whats going on, i cant see thru plastic.

I think mason jars have a limited lifespan.

overtime from repeated heating and cooling they get weak and should be replaced.


I would love to find pyrex jars with caps ,

do they make something like that?

I'm thinking it is the lye that is causing the cracks more so than the heat/pressure. How hot are you making your solutions? I am usually adding my lye slowly enough that if I were to put my hand on the jar, it would be cool enough that it wouldn't burn my hand or even be uncomfortable. Lye definitely eats away at glass. Best to wear safety gear and do your extractions over a sink/bathtub in case of ruptures.

what kinda equipment is used in labs?

If concerned about heat, refrigerate your distilled water prior to mixing with lye. Then it shouldn't go too much above room temperature during the mixing.

The hard plastic water jugs that you find in office settings. Are these safe for caustic water and solvents and if so for approximately how many uses?

here are the bowls I bought, 450 ml fit in them nicely.

I too, use ball mason Jars... I've only done 3 extractions and they all had cracks in them after the very 1st extraction. :/ It didnt look critical so I continued to use them and on the 3rd extraction one of them started leaking. I think I should just recycle the other ones and buy new ones. I couldnt imagine trying to use a milk jug 😶

edit: I didnt realize this was from 6 years ago, sorry about the bump. whoops