Autoclaves for Culture Media Sterilization 

Every microbiology lab needs plenty of sterile culture media. But in many labs, sterilizing culture media and aseptically preparing agar plates continues to eat up too much time. Job number one in any lab should be streamlining your sterilization technique while reducing or eliminating the possibility of microbial contamination of your growth media.

Common tasks—like ensuring sterility of both liquid media and solid media—should be easy. Time required for sterilization shouldn’t rule your schedule. If you run the same culture media sterilization cycle every morning, then you should be able to load the autoclave, push a button, and walk away. Even better, you should be able to load the autoclave the night before, push a button, and arrive to find that growth media ready to pour or agar plates ready to use when you come in the next morning.

Unfortunately, most lab autoclaves—especially low-cost tabletop sterilizers—are general-purpose devices or stripped-down, medical-grade autoclaves with stripped-down control systems. They are basically glorified pressure cookers, with a few preset cycles (none ideal for media preparation), or a simple set of knobs. These autoclaves need babysitting, and are prone to media volume loss, boil-overs, and burst bottles. 

Contamination of agar plates with bacterial microorganisms is the quickest way to torpedo your assay. Sterilization methods that ensure pure culture media require equipment that is up to the job—so you can get on with yours. Priorclave autoclaves are designed for research, with special attention to liquid loads, nutrient broth, and media preparation. Our chamber and valve design discourage evaporation, bottle ruptures, and excessive boiling.

Autoclaves Features for Effective Sterilization of Aseptic Growth Culture

The true key to a good media sterilization autoclave is having the right control system. With Priorclave’s research-ready programmable control system, you have precise control of temperature, timing, and pressure. This substantially simplifies the preparation of agar-containing and high glucose-content media, as well as those containing sodium desoxycholate, bile salts, or other inhibitory agents and media components.

All Priorclave systems come with Timed Freesteaming, Media Warming, and Delayed Start features, as well as One Button Start programming. Timed Freesteaming is primarily used to remove the air burden from difficult loads such as plastic waste, but can also prove handy if you need to melt pre-sterilized growth media.

Our Media Warming feature can be added to any cycle program: Immediately after the sterilization cycle finishes, the autoclave cools to 45ºC, then cycles the chamber between 45ºC and 55ºC until the door is opened. This keeps nutrient media both sterile and ready to pour for hours (even overnight). With Media Warming, there’s no risk of accidentally caramelizing high-glucose media, having your culture media gelling before you get around to using it, or spoiling a batch of sterile media because someone got distracted.

With the Delayed Start function, you can set the time at which your sterilization process begins, up to 24 hours in advance. Your schedule will no longer be dictated by the limitations of your equipment.

Additionally, if your lab runs a lot of liquid loads, you should consider choosing an autoclave with an air ballast. This feature mitigates rapid depressurization by flooding the chamber with cool, pressurized air as the autoclave vents hot steam—the influx of fresh air helps cool the load. An air ballast helps the pressure remain more stable and allows the sample to cool to a safer temperature more gently and gradually. That minimizes boiling and evaporation.

Choosing Your Culture Media Sterilization Autoclave

 

Because every Priorclave comes with the same research-grade programmable control system, any of our units can handle almost any culture media prep regimen. Any cycle program on a Priorclave autoclave—regardless of complexity or length—can be pre-set for One Button Start. Your Priorclave can even be locked down so that operators can run only approved programs—or even just a single specific “foolproof” cycle.

In our experience, many North American labs prefer the tabletop 40L and 60L models for media preparation. While many “economical” tabletop autoclaves are repurposed dental sterilizers—with light-duty plumbing, pressure vessels, and control systems—our research-grade units are optimized for harsh tasks like regular waste loads and media prep (and the occasional boil over that comes with daily media sterilization).

Larger labs with a higher throughput or handling higher volumes of media—especially research institutions and R&D facilities—should consider an autoclave with a higher load capacity, such as Priorclave’s 150L front-loader. More room means more flexibility. The removable middle shelf allows for taller loads, such as several 5L flasks, or more than 60 250 mL flasks across two shelves 

Internationally, vertical “top-loading” autoclaves are our top-sellers for research institutions and labs. These aren’t just energy, water, and space-efficient (offering the same sterilization chamber volume in a dramatically smaller footprint)—they also easily accommodate the tallest flasks, fermentors, and bioreactors, at one-third the price of a comparable front-loading autoclave.