Is an SWB order from Chengdu likely to hold cold chain to Australia?

For reference: SWB · Chengdu · Australia.

I would rather over-plan the first cycle and simplify later.

I am prepared to do the work if someone can tell me which work matters.

How do I make this decision on evidence rather than on feel?

The short version: a spent cold pack on arrival is expected, the solid does not mind, and the pack was never going to last twelve days.

A single phase-change pack in a thin-walled box holds below ten degrees for roughly one to two days at twenty-five degrees ambient, and under a day at thirty-five. On a nine-to-fourteen-day lane the material is at ambient for most of the journey whatever was packed with it.

A pack that arrived hard tells you about the last day of transit only, since it will have melted and, if the ambient dropped, partially refrozen.

Buy a logger if you actually want to know. Everything else is inference.

edited 29 Jul 2026 by w_okoye — tightened the wording; no substantive change

Stated carefully, the domestic leg after arrival is the part most often left in a warm hallway and least often worried about.

A single-use temperature logger costs a few pounds, records the whole journey and converts an argument into a record. If the history matters, this is the answer.

Asking a supplier to hold a shipment during a heatwave is reasonable and the better ones agree; the cost is a week and the benefit is a shorter warm exposure for anything in solution.

The caveat is that a warm transit is survivable for a solid and materially different for a solution.

A liquefied pack is expected. It is not evidence of a problem.

Answer first: for a lyophilised solid the cold chain matters far less than people believe, and for a solution it matters far more than they act as though it does.

Once the parcel arrives, the domestic leg is the controllable part: get it into the refrigerator promptly rather than leaving it in a warm hallway for a day.

Anything shipped in solution is a different risk category, because hydrolysis and deamidation proceed in the aqueous phase and are strongly temperature-dependent.

Phase-change pack hold time is a function of mass, latent heat and insulation, and published figures for small parcels are on the order of one to two days.

A cold pack tells you nothing about the eleven days before the last one.

Lyophilised tolerates the lane. That is the answer for almost every order.

Answering this needs the transit duration and the ambient temperature, and then the arithmetic is straightforward.

Arrhenius behaviour means the degradation rate roughly doubles per ten degrees. A week at thirty degrees is therefore a meaningful exposure for a solution and an immaterial one for a dry solid.

Solutions are a different question and deserve the worry the solids get.

Start with the physical state, because it changes the answer completely and is the first thing to establish.

That is the argument for shipping lyophilised rather than for shipping colder. A dry powder with low residual moisture is stable at ambient for months; the pathways that matter need water.

Arrhenius kinetics predict approximately a doubling of degradation rate per ten-degree rise and are the standard basis for cold-chain design.

The domestic leg is the part you control. Refrigerate it promptly.