Astell has been helping organisations achieve effective steam sterilisation for more than 140 years. Over that time — and in particular through validating machines across a large installed base — we have built an unusually direct picture of what laboratories genuinely put through their autoclaves, rather than what a specification assumes. This article shares that picture in anonymised, aggregate form: first the overall pattern, then a breakdown by the kind of site doing the work.
Why real loads matter
An autoclave is chosen well or badly by its loads, not its label. Knowing what actually goes into chambers across more than a hundred real laboratories is the difference between specifying for a brochure scenario and specifying for the work in front of you. Two things follow from the data: there is a common core almost everyone shares, and there is a distinct signature for each type of site.
The common core
By a clear margin, the most common single load everywhere is the humble Duran bottle — 500 ml and 1-litre sizes are the everyday workhorses — carrying prepared media, broths and water, often only part-filled. Close behind come petri dishes and plates, then tubes and vials, universals, and pipette-tip boxes: the routine microbiology and cell-culture consumable stream. And running alongside all of it is decontamination on the way out — gloves, lab coats and tissue bagged in steri-bags, plastic discard and sharps. That core is remarkably consistent from one lab to the next.
Where sites differ: loads by facility type
Beyond that core, the type of site shapes the load — and, in turn, the machine. The summaries below show the pattern from the validated installed base. The formats reflect what these sites actually run, drawn from the service data; the suggested options are engineering guidance rather than a count. Some entries rest on a handful of sites and are marked accordingly.
Universities & teaching labs
Common loads: Media and water in Durans; petri dishes and plates; pipette-tip boxes; Nalgene and sample bottles; gloves, coats and tissue as waste.
Formats commonly run: A broad mix: top-loading, front-loading and front-loading vacuum, plus benchtops for smaller labs.
Options that suit the work: Multiple stored programmes; simple, repeatable operation for rotating users; cooling matched to media throughput.
Plant & agricultural research
Common loads: Above all, spent soil and plant waste (often in dedicated boxes or bins); growth media in Durans; coats and general waste.
Formats commonly run: Front-loading vacuum and vacuum-with-drying units — a vacuum-heavy population.
Options that suit the work: Pre/post-vacuum pulsing for dense loads; heating jacket and drying for bagged waste; large square chamber for bulk trays and boxes.
Biomedical & cancer research
Common loads: Culture media and liquids in Durans; culture flasks (including 2-litre flasks); tubes and vials; tip boxes; gloves, coats and plastic discard.
Formats commonly run: Top-loading, front-loading vacuum and large square vacuum sterilisers.
Options that suit the work: Vacuum air removal for mixed loads; effective liquid cooling; a dedicated discard programme.
Pharmaceutical manufacturing & CDMOs
Common loads: Strongly liquid-led: media and water in Durans and universals across many fill volumes; petri dishes.
Formats commonly run: Front-loading, predominantly (small sample: approximately 6 sites).
Options that suit the work: Load-sensed timing and flexible probes for liquids; effective cooling; full printout, audit trail and documentation for validation.
Filtration & bioprocessing
Common loads: Capsule filters, cartridge and housing assemblies, 47 mm and 142 mm disc holders, tubing and steri-bags; TSB media in Durans.
Formats commonly run: Large square vacuum sterilisers, plus benchtop (small sample: approximately 5 sites).
Options that suit the work: Pre/post-vacuum pulsing for complex assemblies; vacuum-and-jacket drying; validation documentation.
Food & beverage QC
Common loads: Media and sample liquids in Durans; plates and petri dishes; sample bottles; filter steri-bags.
Formats commonly run: Front-loading and benchtop (small sample: approximately 3 sites).
Options that suit the work: Compact footprint; cooling matched to routine QC; stored programmes for media and discard.
Device & personal-care manufacturing
Common loads: Small vials and containers, often saline-filled; blisters and sensor components; trays; fluids in Durans.
Formats commonly run: Benchtop, predominantly, with some large square vacuum (small sample: approximately 7 sites).
Options that suit the work: Fluids and waste-destruct programmes; load-sensed timing; small footprint.
Reading the signatures
A few of these signatures are worth drawing out, because they show how directly the load drives the machine.
Plant and agricultural research is the most distinctive: its dominant, high-volume load is not glassware but waste — spent soil and plant material decontaminated in bulk — and it runs a strikingly vacuum-heavy fleet, because dense, bagged waste needs thorough air removal and often drying. Pharmaceutical manufacturing sits at the opposite end: its loads are overwhelmingly liquids in bottles and universals, run on front-loaders, where the priorities are getting heat into the centre of a bottle and proving it happened. Filtration and bioprocessing is different again — the load is the hardware itself, and the complex, air-trapping geometry of filter assemblies is exactly why those sites run large vacuum sterilisers. And device and personal-care manufacturing shows up as a benchtop population handling small, high-value vials and components rather than bulk glassware.
The cycles behind the loads
Underlying all of this is a consistent set of cycles. Most machines carry a small cluster of programmed temperatures: around 115 °C for heat-sensitive media, 121 °C as the standard, 124 °C commonly alongside it, and 134 °C reserved for wrapped instruments and containment work. In other words, the field runs a handful of well-worn cycles far more than it runs exotic ones — and the differences between sites show up more in loads, formats and options than in temperature.
What this means for specifying an autoclave
The lesson is to specify around your real loads rather than a generic ideal. Start from what actually goes in — the bottles, the plates, the waste, the specialist items — recognise which facility-type signature yours most resembles, and let that guide chamber size, format and the options that earn their place. It is the least glamorous step in buying an autoclave, and consistently the most valuable.
How Astell can help
In this kind of assessment, Astell can help you translate a real load list into the right chamber size, format, cycles and options — grounded in what laboratories like yours genuinely process. If you have loads you would like to talk through, or another autoclave-related question, contact Astell to discuss it. With hundreds of autoclaves available, highly customisable builds, versatile installation options and an expert team of in-house service engineers, Astell has the skills and experience to help solve your steam sterilisation challenges. Contact Astell today at info@astell.com.
