c/coldchain wiki

What this community is for

Temperature and stability in the real world: what an excursion actually costs you, why lyophilised powder is far more forgiving than reconstituted solution, how to read a logger CSV, and how to photograph a failed shipment so the conversation with the vendor is short.

c/coldchain was created on 19 Oct 2023 and currently has 27,400 members and 95 captured submissions. It sits in the second tier of the site, which mostly affects how fast a question gets answered rather than how well.

Rules, and why each exists

Community rules come first, then the six site-wide rules that apply everywhere on GLP Research Hub. Community rules are enforced by the moderators listed at the bottom of this page; site rules are enforced by everyone.

1. Excursion claims need a logger trace or a photo taken at unboxing. "It felt warm" is not data.
2. No tracking numbers, ever. They identify you and the recipient.
3. Stability claims need a source or an explicit "this is my guess" label.

And the site rules, which are short on purpose:

1. Independent community. Nobody here sells anything, and anyone who tries is banned.
2. Not medical advice. Describe what you did; never prescribe to a stranger.
3. Claims need evidence. Batch numbers, dated screenshots, independent test reports, or a citation.
4. No referral links, discount codes or affiliate URLs. Permanent ban, no appeal.
5. No contact handles, wallet addresses or tracking numbers — they identify people.
6. Be recognisably decent. Disagree hard, insult nobody.

Terms you will see

Vocabulary that turns up constantly in c/coldchain. Each links to the topic page, which collects every submission that touches it.

• cold chain — keeping material within a temperature range through transit and storage.
• excursion — time spent outside the intended temperature range; an integral, not an event.
• data logger — a cheap recorder that turns "it felt warm" into a CSV.
• lyophilised — freeze-dried. The dry state, and much more robust than the solution.
• stability — how quickly the molecule degrades under given conditions.
• ice pack — coolant with a finite budget; it is meant to exhaust before delivery on long lanes.
• packaging — insulation plus thermal mass. Most bad packaging is missing the mass.

Start here

The twelve highest-scoring submissions in this community. Not necessarily the most correct — the most agreed-with, which is a different thing, and worth remembering when you read them.

1. three years of packaging threads, summarised so you do not have to read them — 5.4k points, 32 comments, 2 years ago
2. [Discussion] the excursion advice in here is 2 years out of date — 4.7k points, 25 comments, 1 year ago
3. [Meta] proposal — a flair for packaging posts — 4.5k points, 31 comments, 6 months ago
4. cold chain — 23 things I got wrong before I got it right — 4.5k points, 33 comments, 2 years ago
5. [Discussion] can we stop arguing about excursion until somebody posts a number — 4.4k points, 51 comments, 1 year ago
6. [Discussion] data logger is doing more work than we give it credit for — 4.2k points, 41 comments, 2 years ago
7. [PSA] stability is not what most of this community thinks it is — 4.2k points, 33 comments, 11 months ago
8. the data logger question that gets asked weekly, answered properly — 4k points, 34 comments, 1 year ago
9. [Discussion] the packaging advice in here is 2 years out of date — 3.9k points, 55 comments, 1 year ago
10. [Meta] the stability rule is doing its job and people should stop complaining — 3.8k points, 52 comments, 2 years ago
11. the ice pack thing finally clicked for me and I want to write it down — 3.8k points, 13 comments, 1 year ago
12. ice pack — 19 things I got wrong before I got it right — 3.7k points, 35 comments, 1 year ago

Asked constantly

• reconstituted vial left out for five hours — bin it or not
• [Question] reconstituted vial left out for five hours — bin it or not
• light exposure matters more for some compounds than others and nobody tabulates it
• [Question] how do you actually verify ice pack
• [Meta] proposal — a flair for data logger posts
• [Question] Australia — has anyone got a straight answer on packaging
• reading excursion threads from 2024 and half of it aged badly
• [Question] France — has anyone got a straight answer on packaging
• ice pack is the most under-discussed thing on this board
• why does nobody talk about excursion

If your question is on that list, read the answers there first. If it is not, ask it — that is what the community is for, and "this has been asked" is only a helpful reply when it comes with a link.

Who runs this

Moderation here is done by volunteers who also post as normal members. They are not clinicians, not vendors, and not paid.

• u/mod_cold_room — c/coldchain mod. Fridge thermometer evangelist. Ask me about excursion tables.
• u/coldchain_karen — I own four data loggers and I will lend you one. Excursions are survivable; ignorance is not.
• u/ice_pack_audit — Photograph the pack the moment you open it. Liquid gel pack = the chain broke.
• u/usb_logger_ursula — £18 logger, CSV export, whole argument settled in 30 seconds.