What Is a Lab Incubator? Definition, Types, and Uses

A lab incubator is an enclosed chamber that holds a stable, controlled environment — usually temperature, and often humidity and CO2 concentration too — so that living cells, microorganisms, or biological samples inside it grow or behave predictably. It solves a simple but critical problem: cells and microbes are exquisitely sensitive to their surroundings, and the open lab bench is none of the things they need. Room temperature drifts, room air has the wrong gas mixture and humidity for most cultures, and ambient microbial load is far higher than a culture vessel can tolerate without contamination. An incubator removes that variability so an experiment’s outcome reflects the biology being studied, not an uncontrolled swing in temperature or a contaminating mold spore that landed on an open plate.

Incubators are used anywhere biological material needs to grow or be held under defined conditions: cell and molecular biology labs (mammalian cell culture), microbiology and clinical labs (bacterial and fungal culture, diagnostic identification), food, water, and environmental testing labs (regulatory assays like Biochemical Oxygen Demand testing), IVF and reproductive labs (embryo culture), and industrial/biotech settings (fermentation, strain development, quality control). The common thread is reproducibility: whatever grows in the incubator today should grow the same way tomorrow, because the environment it experienced was held constant.

The Three Main Types of Lab Incubator

“Incubator” covers several distinct pieces of equipment built around the same core idea — a controlled chamber — but tuned for different biology.

CO2 Incubator

Built for mammalian and other cell culture, a CO2 incubator maintains temperature (commonly close to human body temperature for mammalian work), a controlled CO2 atmosphere, and high relative humidity together. The CO2 does real chemical work here: most cell culture media are buffered with sodium bicarbonate, and the dissolved CO2 in the chamber air keeps that buffer system at the pH the cells need — pull the CO2 out and the medium drifts alkaline. High humidity, in turn, slows evaporation from open culture dishes so osmolality doesn’t creep upward over a multi-day culture. Chamber design (water-jacketed vs. direct-heat/air-jacketed) and CO2 sensing technology (infrared vs. thermal-conductivity) are the two biggest differentiators between models — CASRAI’s dedicated CO2 incubator buying guide covers that selection decision in depth, and the companion CO2 incubator calibration and temperature-uniformity mapping guide covers how a unit already in service gets qualified and kept in spec.

Bacteriological (Dry) Incubator

A simpler, temperature-only chamber — no CO2 control, and usually no active humidity control — built for bacterial and fungal culture on agar plates or in broth, and for general microbiology work where the organism doesn’t need a bicarbonate-buffered atmosphere. Regulatory and environmental labs use a close relative of this design, a BOD (Biochemical Oxygen Demand) incubator, held at a standard test temperature for a fixed multi-day water- or wastewater-quality assay; see BOD incubator vs. COD reactor for how that specific instrument differs from the chemical-oxidation method it’s often compared against.

Shaking Incubator

A bacteriological incubator combined with an orbital or reciprocating shaking platform, used to keep liquid cultures — bacterial, yeast, or other suspension cultures — aerated and evenly mixed as they grow. Constant agitation keeps dissolved oxygen available throughout the culture and prevents cells from settling, which matters for fermentation work, plasmid prep cultures, and any protocol that specifies a shaken liquid culture rather than a static plate.

Beyond these three, the same core concept — a small, tightly controlled chamber — also shows up in more specialized forms, such as platelet incubators used in blood banking to agitate platelet units at a controlled temperature; see platelet agitator vs. platelet incubator if that specific use case is what brought you here.

What an Incubator Is Not

A few adjacent pieces of equipment get confused with an incubator because they share the bench or a similar-sounding name:

• Biosafety cabinet / laminar flow hood: provides a sterile, airflow-controlled workspace for handling an open culture without contaminating it or exposing the handler — it does not hold or grow anything long-term. In a typical cell culture workflow, sterile manipulations happen in the hood, then the vessel goes back into the incubator to actually grow.
• Autoclave: sterilizes media, glassware, and waste using pressurized steam heat. It kills biological material; an incubator cultivates it. The two are often used in sequence — autoclave media to sterilize it, then incubate a culture in it.
• Refrigerator/freezer or cold storage unit: holds biological material at low temperature to slow or halt growth and metabolism for storage. An incubator does the opposite job — it actively promotes growth under favorable conditions.
• Business/startup “incubator”: an unrelated, purely organizational use of the same word — a program that supports early-stage companies. It shares no equipment or lab function with the instrument described on this page.
• Neonatal (infant) incubator: a clinical device that maintains a controlled thermal environment for a premature or ill newborn. It works on the same basic principle — a controlled chamber — but is a patient-care device, not a research or laboratory instrument, and is regulated and designed accordingly.

Why This Matters for Research Administration and Lab Management

For staff who manage lab space, budgets, and compliance rather than run the bench work themselves, a few practical points recur:

• Procurement is a real decision, not a commodity purchase. Incubator type, chamber design, and sensor technology materially affect contamination risk, recovery time after the door opens, and total cost of ownership — see the CO2 incubator buying guide for the tradeoffs worth budgeting time to evaluate before a purchase order goes out.
• Calibration and qualification are compliance touchpoints. Temperature (and, for CO2 units, gas concentration) uniformity across the chamber needs periodic verification and documentation, particularly under GLP, ISO 17025, or similar quality systems — the calibration and uniformity-mapping guide walks through what that process actually involves.
• Space and utility planning matters early. CO2 incubators need a CO2 gas supply (cylinder or house line), a data/alarm connection is increasingly expected for continuous monitoring, and chamber capacity should match projected culture volume — undersizing is a common and expensive planning mistake.
• Incubators are a recurring line item in equipment inventories and space audits, and their service/calibration records are frequently what an accreditation or grant-compliance review asks to see first.

Related Lab Equipment

An incubator is one piece of a larger cell-culture and microbiology workflow. Two other pieces of fundamental lab equipment it’s commonly used alongside: a water bath, used to pre-warm media to incubation temperature before it goes anywhere near a culture, and a spectrophotometer, used to measure culture density (optical density) on samples pulled out of the incubator to track growth over time.

Frequently Asked Questions

What’s the difference between a CO2 incubator and a bacteriological incubator?

A CO2 incubator actively controls CO2 concentration and humidity in addition to temperature, which matters for bicarbonate-buffered mammalian cell culture media. A bacteriological (dry) incubator controls temperature only and is built for bacterial/fungal culture that doesn’t need a controlled gas atmosphere.

Why do CO2 incubators need humidity control?

High humidity slows evaporation from open culture dishes and flasks. Without it, water loss over a multi-day culture concentrates the medium’s salts and nutrients, shifting osmolality away from what the cells were cultured to tolerate.

What does a shaking incubator do differently from a standard incubator?

It adds an orbital or reciprocating shaking platform so liquid cultures stay aerated and evenly suspended as they grow, which static incubation can’t provide for a suspension culture.

Do all incubators need a CO2 supply?

No. Only CO2 incubators (built for mammalian cell culture) need one. Bacteriological and shaking incubators used for standard microbiology work are typically temperature-only and don’t require a gas connection.

How is an incubator different from an autoclave?

They do opposite jobs. An autoclave uses pressurized steam heat to sterilize (kill microorganisms on) media, glassware, and waste. An incubator provides the controlled conditions for living cells or microorganisms to grow. Media is commonly autoclaved first, then used inside an incubator.