Combustion (Dry Heat Sterilization) of Glassware

Procedure for combustion sterilization of glassware to remove organic residues and contaminants.

Combustion (Dry Heat Sterilization) of Glassware, v1.0 Kathryn E. Caruso · 0009-0003-2436-1791 Foreman Lab · Center for Biofilm Engineering, Montana State University Updated March 2026

How to cite this protocol Caruso, K.E. (2026). Combustion (Dry Heat Sterilization) of Glassware, v1.0. Foreman Lab, Center for Biofilm Engineering, Montana State University. https://kathryncaruso.github.io/methods/combustion-glassware/

Combustion (Dry Heat Sterilization) of Glassware

Standard Operating Procedure

Purpose

Combustion (dry heat sterilization) removes all organic residues from glassware, ensuring tubes and vessels are free of contaminants that could interfere with growth, OD readings, or sensitive assays. Used for any glassware that must be organically clean before use.

1 Safety

Warning: Combustion oven reaches extremely high temperatures.

PPE:

  • Lab coat
  • Heat-resistant gloves (when loading/unloading oven)
  • Safety glasses

Hazards:

  • Thermal burns from hot oven and glassware
  • Thermal shock can crack glass if cooled too quickly

2 Equipment and materials

  • Combustion oven
  • Aluminum foil
  • Glassware to be combusted (e.g., borosilicate glass culture tubes)

3 Procedure

  1. Wash glassware if needed (remove visible residues)
  2. Inspect glassware — only use items without scratches, especially near the bottom where OD may be read
  3. Wrap glassware loosely in aluminum foil
  4. Place in combustion oven
  5. Combust at 450°C for 5 hours
  6. Allow to cool completely inside the oven before removing — do not open the door while hot (thermal shock can crack glass)
  7. Keep wrapped/covered until use

Important

Combustion takes approximately 1 day including heat-up and cool-down. Plan accordingly.

Note

Do not combust any plastic items (caps, closures, etc.). These must be autoclaved — see Autoclave Sterilization and Decontamination.