[Brizo]

@mod: Please move this to better section if there is one...

I've spent a small fortune already & failed to find a robust storage container that meets requirements, so thought I would ask advice from you lab guys.

I need a storage solution for extremely pungent & perishable foodstuffs in the form of plant matter(Herbs).

Requirements.

Air-tight:
Contents being stored degrade quickly on contact with air, tested various types of plastic food containers, they all air-exchange & leak smells, even the big brands that claim to have a vacuum tight seal.

Long term storage:
Airtight seal for 3 years.

Food/Medical/Durable/Inert:
Suitable for daily use without polluting contents with plastic powder/residue, eg disintegration of lid from repeated access.

Clean:
At the moment I'm using 99% Isopropyl to sterilise & clean glass reagent bottles, which seems to work well.

After the failed plastic food containers, I moved to glass reagent bottles with glass stopper(Apothecary Bottles), these have been the best so far at containing smells, however I've noticed if you turn the reagent upside down with stopper in place they leak water so I'm assuming they are not airtight.

These reagents were made in China, the better ones are stamped by Shunui glass company, some stoppers rock slightly in the joint, rotating the stopper with trial & error makes a tighter fit, but they still leak water.  These bottles were relatively cheap:
http://www.aliexpress.com/item/1000ml-Lab-Glass-Reagent-bottle-wide-mouth-with-ground-stopper/611405846.html

The equivalent bottle from a reputable western manufacturer are ten times the price:

http://www.mercateo.co.uk/p/163UK-9071954/Wide_neck_reagent_bottles_DURAN_amber_glass_with_NS_glass_stopper_cap_1000_ml.html?quantity=1


Do I really need to pay $170 for a fully airtight 1ltr glass bottle or maybe glass stoppers are unable to create a fully airtight seal?

I've been looking at polypropylene screw cap bottles:

Are these 100% airtight?

Will the lid disintegrate with daily use and pollute the contents with plastic particle?

How would I safely sterilise the lids, I'm assuming I can't use iso99?

I'm open to other solutions?

[Arkcon]

Ground glass stoppers (like the ones you've shown) are reasonably air-tight over the short term, for example, I might use them to hold samples for an iodine titration, over the day.  You can add silicone grease to the stopper to seal it better.  Now this sort of bottle is useless for shipping a substance, this is just for lab use.

Glass is generally assumed to be the most non-reactive container.  There are plenty of caveats with this assumption -- lower quality of glass, strong base does attack glass, and other rare reactions.  And its expensive, and heavy, and somewhat fragile.

A screw-cap stopper with a Teflon liner is good.  Usually, its a soft silicone rubber liner, with a thin Teflon coating.  Screwing the cap on tightly deforms the silicone for a seal, and the Teflon is non-reactive.  This sort of container is required for samples that need to be shipped, unchanged, for analytical purposes.  Or perhaps, to insure stability over the period of a couple of years.

You've mentioned some other requirements, and we'll get to those.  But we still need a clearer view of what you applications is.  You've got some herbs, and you're perhaps making isopropanol tinctures.  But you seem a little obsessed with 100% airtight, sterile and non reactive containment.  Why?  Do you ship these?  Because my solutions above are expensive.  What preservatives do you add?  Because without them, substances will last months or maybe a year, maybe less.  If the contents won't endure that long anyway, why go so far to preserve them?

You have to think about things like that before you start making purchases.

[Brizo]

You've mentioned some other requirements, and we'll get to those.  But we still need a clearer view of what your applications is.  You've got some herbs, and you're perhaps making isopropanol tinctures.  But you seem a little obsessed with 100% airtight, sterile and non reactive containment.  Why?  Do you ship these?  Because my solutions above are expensive.  What preservatives do you add?  Because without them, substances will last months or maybe a year, maybe less.  If the contents won't endure that long anyway, why go so far to preserve them?

Containers are not for transit.

The herbs being stored will eventually be heat vaporised & medicinally inhaled by patients, so any kind of contaminant would be vaporised and inhaled along with the medicine, this is my worry with plastic lids & sanitation.

The herbs in question have a very strong pungent odour, they will stink out the containing cupboard, room and entire building if the container is not completely air tight.

The herbs are expensive & will quickly lose potency when exposed to air..even a few hours in the open could mean a 20-40% loss.

I don't add any preservatives, the herbs have been cured, so might survive 1-2 years if completely airtight & kept stable, I've heard of 2-3 years using heat/vacuum sealed in plastic envelopes, I said 3 years to add emphasis....did I mention they have to be air tight

Realistically, most herbs will be used within 1 year, some bottles might be stored for months at a time without being accessed, other bottles will be accessed several times per day every day, the daily bottles will be re-filled as they empty, this cycle could go on for years, a well used glass stopper might last a century but how long does a plastic lid last before potentially contaminating its contents...so the lid has to be fit for purpose & contaminant safe.

I've been using the glass stopper bottles to extract oil from the herbs using solvents, iso99/ethano96 and they seem fine for that purpose.  So really the storage requirements only concern dry herbs and maybe some oils extracted from those herbs. 

You have to think about things like that before you start making purchases

It's been an expensive lesson.

[Brizo]

Can soda-lime, flint glass be used with iso99/abv96 or does it have to be borosilicate?

http://en.wikipedia.org/wiki/Soda-lime_glass
http://en.wikipedia.org/wiki/Isopropyl_alcohol
http://en.wikipedia.org/wiki/Rectified_spirit#Germany

[curiouscat]

Can you use one of those vacuum sealing thingys? Or add some inert gas like N2?

Not sure what your scale / budget is.

Or use something like  a dessicator. Those use ground glass plus grease for a seal I think.

[Brizo]

Vacuum sealing via a desiccator wont allow easy access.

Adding gas/grease into the equation defeats the purpose of all-glass containers.

[Brizo]

^^Maybe I was too hasty, a seed has been planted

Basic testing on various glass stopper reagents shows none are air/water tight, filling reagent with water then standing on head causes a slow/delayed leak, holding bottle underwater with stopper in place yields the same, it appears reagents are almost airtight but not quite.  Duran/Schott didn't reply to my are your reagents airtight? email, ...but even cheap reagents make a better seal than plastic food containers.
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How about cheap soda-lime reagents stored in a vacuum chamber?

Store reagents containing Herbs in a vacuum,
Every morning decant just enough herb into the non-vacuum reagent,
Every evening decant the remaining herb back into the vacuum reagent.

I would need to control the humidity, apparently a lack of oxygen can encourage mould.

I'm a real novice when it comes to stuff like this so any feedback is welcomed, particularly reasons why it might not work.

In some conditions these reagents might inadvertently create an airtight seal, ....are there any safety concerns for a bottle filled with air inside a vacuum chamber?

Will the vacuum chamber pull the air from a nearly airtight bottle?