Autoclave: Uses and How to Use It
Autoclave: Uses and How to Use It
An autoclave sterilises with pressurised saturated steam, usually at 121 °C and about 1 bar above atmospheric pressure for 15–20 minutes, killing all microorganisms including spores. It is used to sterilise media, glassware, surgical instruments and biological waste.
What is a autoclave used for?
- Sterilising culture media and solutions before use.
- Sterilising glassware, tips and metal instruments.
- Decontaminating biological waste and used cultures before disposal.
Parts of a autoclave
- 1Lid and lock – holds the pressure; cannot open while pressurised
- 2Pressure and temperature gauges – show conditions inside the chamber
- 3Safety valve – releases excess pressure
- 4Chamber and basket – holds the load; water in the bottom
How to use a autoclave
Check the water level
Make sure distilled or deionised water in the bottom of the chamber reaches the mark (1). Tap water leaves scale that damages the heater.
Loosen bottle caps and add indicator tape
Loosen bottle caps about a quarter turn so steam and air can escape (1), and apply autoclave indicator tape (2). Do not pack the basket too tightly.
Lock the lid, select 121 °C and the time
Close and lock the autoclave, select a program or set 121 °C with a time to suit the load (e.g. 15–20 minutes for small volumes, longer for large ones), then start (1). Sterilising time counts from when the temperature is reached.
Open only at zero pressure and lower temperature
Wait until the gauge reads 0 and the temperature is below about 80 °C (1). Open the lid slowly while standing to one side away from the steam, wearing heat-resistant gloves.
Common mistakes
- Autoclaving tightly capped bottles: they can burst from the pressure.
- Opening before the pressure is zero or lifting liquids that are still boiling: steam burns and boil-over.
Care and safety
- Drain and change the water regularly and clean the chamber and drain strainer.
- Inspect the lid gasket and safety valve as the manufacturer schedules.
SOP for using a autoclave
A summary of the standard operating procedure (SOP) for a autoclave that your laboratory can adapt. Each step is explained in the how-to section above.
1Protective equipment
- A buttoned, long-sleeved lab coat.
- Long heat-resistant gloves.
- Safety glasses or a face shield when opening and handling hot liquids.
2Before use
- Only users trained by the instrument supervisor may operate it alone; read the manufacturer's manual.
- Distilled water reaches the mark; the lid gasket is intact and clean.
- The load contains nothing flammable, corrosive, radioactive or bleach; bottles are not sealed.
- Waste goes in autoclave bags left slightly open inside a heat-proof secondary tray.
3Procedure
4After use
- Open only at zero pressure and lowered temperature; let liquids stop boiling before lifting them.
- Check the indicator tape changed colour and record the cycle in the log (date, load, temperature, time, operator).
- Switch off, drain the water as scheduled and dry the chamber.
5Verification & calibration
- Use biological indicators (Geobacillus stearothermophilus spores) periodically, e.g. monthly and after repairs; results must be negative.
- Calibrate the temperature sensor and pressure gauge and test the safety valve as scheduled.
- Periodic service and electrical safety test by a technician as the manufacturer recommends (usually once a year).
6Emergencies
- Steam leaking from the lid or overpressure: switch off the heater, step away, do not force it open and report it.
- Steam or hot-liquid burn: cool under running water for 10–20 minutes and seek medical help.
- Smoke, burning smell or electric shock: switch off at the socket if safe, never use water, use a CO₂ extinguisher and report it.
A print-ready version with purpose, scope, illustrated procedure, verification and sign-off boxes. Fill in your own document number and effective date.
Download the SOP (PDF, A4)Types and sizes
Portable (stovetop or electric) autoclaves suit small labs; vertical and benchtop autoclaves suit microbiology labs; large horizontal autoclaves handle big loads. Class N is for unwrapped solids; class B with pre-vacuum is for porous, hollow and wrapped items; class S is for loads specified by the maker.
Autoclave at AMI Scientific
Examples of autoclave available in our store. Prices exclude VAT.
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Frequently asked questions
What temperature and time does an autoclave use?
Usually 121 °C for 15–20 minutes for small volumes. Large liquid volumes need longer so all the liquid reaches 121 °C.
How do you know the autoclave really sterilised?
Indicator tape only shows the load was heated. Sterilisation is proven periodically with biological indicators containing Geobacillus stearothermophilus spores.
Related equipment
Compiled by the AMI Scientific team from standard laboratory practice. Illustrations: AMI Scientific. Updated: 06-11-2026.
Need a autoclave for your laboratory?
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Available at AMI Scientific
Autoklaf Portabel Infitek STP-M24
From Rp8.437.185