What Is an Erlenmeyer Flask? Types & Uses

Last verified: October 6, 2026. An Erlenmeyer flask, also called a conical flask, is a piece of laboratory glassware with a flat base, a cone-shaped body that tapers upward, and a short, narrow cylindrical neck. It is named for the 19th-century German chemist who introduced the design. Its shape is one of the most recognizable symbols of a laboratory, and it is a standard item on benches in chemistry, biology, and teaching labs alike.

The shape is functional rather than decorative. The wide, flat base sits stably on a bench or hot plate and gives liquid a large surface for heating or stirring. The sloping sides and narrow neck mean the contents can be swirled vigorously, and the liquid tends to stay inside rather than splashing out, since the narrowing walls direct it back down. The neck is also the right size to accept a stopper, a foam plug, or a loose cap, and it provides a handle for holding or clamping the flask. A beaker has straight sides and a wide mouth, and liquid swirled in one spills easily; the Erlenmeyer shape is a response to exactly that problem.

This page is general educational information, not clinical, laboratory, or safety training. Always follow your institution’s procedures and the manufacturer’s instructions for the glassware and equipment you use.

What an Erlenmeyer Flask Is Made Of

Most Erlenmeyer flasks are made from borosilicate glass, a type of glass chosen because it resists chemical attack and tolerates heating and cooling far better than ordinary glass. Plastic versions, commonly polycarbonate, polypropylene, or similar materials, are also widely used, particularly for cell culture and other work where breakage, weight, or disposability matter. Each material has trade-offs:

• Glass is reusable, can usually be heated and sterilized, and resists many solvents. It is heavier and can chip, crack, or shatter if dropped or abused.
• Plastic is lighter, more shatter-resistant, and often supplied sterile for single use. It generally cannot take direct heating, and it may be incompatible with some solvents. How a given plastic behaves under sterilization is covered in which plastics are autoclavable.

Flasks are typically printed with approximate graduation marks and a writing patch. Those marks are meant as a rough guide to volume, not as a measurement of record. When precision matters, a different instrument is used, as discussed below.

Who Uses an Erlenmeyer Flask, and Why

The flask is among the most versatile pieces of glassware in a laboratory. Common uses include:

• Mixing and swirling solutions. The shape allows a user to swirl the contents by hand, or place the flask on a stirrer or shaker, without losing liquid.
• Heating liquids. Borosilicate flasks can be heated, for example on a hot plate, and the narrow neck helps limit evaporation and splashing. Heating must always follow the safety rules of the facility and the glassware’s own limits.
• Titration. In chemistry teaching and analysis, the flask holds the solution being titrated, since the swirling motion mixes added reagent into the liquid without spilling it.
• Growing microbial and cell cultures. Flasks, often with a cotton or foam plug or a vented cap, hold liquid culture medium on a shaker so cultures grow in suspension with air exchange.
• Preparing and storing media and reagents. Culture media, buffers, and other solutions are often made and briefly stored in flasks, particularly when they will be sterilized in an autoclave before use.
• Filtration setups. A heavy-walled variant, the filtering flask, holds filtrate during vacuum filtration (see below).
• Collecting and holding samples. The narrow neck suits stoppering, and the shape suits temporary storage in a lab.

Research groups that grow organisms or cells often start in flasks on a shaker and later scale up to a bioreactor when control over conditions or larger volumes is needed. Flasks on a shaker are a common way to test and optimize conditions before that step.

Types of Erlenmeyer Flasks

• Standard narrow-mouth flasks are the general-purpose form, available in a wide range of volumes from small to very large.
• Wide-mouth flasks have a larger opening that makes it easier to add solids, reach inside, or clean the glass. They are less well suited to retaining vapor or to tight swirling.
• Baffled flasks have indentations or ridges in the lower wall that disturb the liquid as the flask is shaken. This increases mixing and the amount of air dissolving into the culture, which suits organisms that need a lot of oxygen. Because the baffles can also make cleaning harder and encourage foaming, whether they fit a given culture is an application decision.
• Ground-glass-joint flasks have a neck finished to accept a matching glass stopper or fitting. They are used when a tight seal or connection to other glassware is needed.
• Filtering (side-arm) flasks are a thick-walled version with a side port to connect to a vacuum source. They are built to withstand reduced pressure and should not be treated as interchangeable with ordinary flasks.
• Plastic and disposable flasks are common in cell culture, where they are supplied sterile with a vented or sealed cap.
• Specialty flasks include those with a built-in screw cap, amber glass to protect light-sensitive contents, or specific geometries for particular culture protocols.

How an Erlenmeyer Flask Differs From Adjacent Equipment

• Beaker. A beaker has straight sides and a wide open top. It is easy to pour from and to reach into, but it is poorly suited to swirling, to limiting evaporation, or to being plugged or stoppered. A flask is usually the better choice when the liquid will be agitated, covered, or heated for some time.
• Volumetric flask. A volumetric flask is flat-bottomed and pear-shaped, with a long narrow neck and a single etched calibration line. It exists to make one precise volume of solution, not to heat, boil, or culture. An Erlenmeyer flask’s printed marks are only approximate. The two have different jobs, and a precise solution should not be made in an Erlenmeyer flask when accuracy matters.
• Round-bottom flask. A round-bottom flask has a spherical body that distributes heat evenly and resists pressure well, and is used in chemical synthesis and distillation, usually supported in a heating mantle or clamp. It cannot stand on its own on a flat bench without a support.
• Graduated cylinder. A graduated cylinder is a tall, narrow vessel used to measure liquid volume with moderate accuracy. It is a measuring tool, not a mixing or heating vessel.
• Culture flasks designed for cell culture. Tissue-culture flasks have a flat, treated surface for attached cells and are a different product; Erlenmeyer flasks are generally used for cells and microbes grown in suspension.

How It Is Used With Shaking and Incubation

A very common modern use of the flask is in suspension culture on a shaking platform. A flask with a limited volume of medium sits on a platform that moves in a circular or back-and-forth motion, often inside an incubator. The motion keeps cells suspended and exchanges gases between the liquid and the air above it. Filling a flask only partway, rather than to the neck, is typical because the headspace and the liquid’s surface area drive how much oxygen reaches the culture. Specific fill volumes and speeds are protocol-dependent and are set by each lab’s method rather than by general rule. For the equipment used to hold flasks in that motion, see what an incubator shaker is.

Practical Notes for Research-Administration, Procurement, and Lab-Management Readers

• Glass versus plastic. Reusable glass has lower per-use cost but requires washing, sterilizing, and inspection time; single-use plastic costs more per use and generates waste but saves labor and can reduce cross-contamination risk. The right balance depends on the lab’s workflow and budget.
• Safety. Glass flasks can break when dropped or stressed, and cracked or chipped glass should be removed from use. Heating, vacuum, and pressure each have specific rules: only glassware designed for a given condition should be used under it, and a standard flask should never be used for vacuum work. Institutions provide training and policies on all of this.
• Sterilization. Many labs autoclave glass flasks. Materials and closures must be compatible with the method used, and a sealed vessel must not be subjected to pressure it was not designed to hold.
• Calibration limits. Because printed marks on an Erlenmeyer flask are approximate, procedures that require accurate volumes should specify the right measuring instrument. This is relevant to quality systems and audits.
• Breakage and replacement budgets. Glassware is a recurring consumable cost. Teaching labs and core facilities in particular should plan for routine replacement.
• Standardizing sizes. Matching flask sizes to shaker clamps and incubators avoids purchases that do not fit existing equipment.

The Short Version

An Erlenmeyer flask is a flat-bottomed, cone-shaped flask with a narrow neck. Its shape lets liquid be swirled, heated, and covered with little loss, so it is the standard vessel for mixing, titrating, preparing media, and growing suspension cultures. It is not a precision measuring instrument, and it comes in glass and plastic forms with different limits on heat, vacuum, and chemicals. Choosing the right variant, and the right measuring tool when accuracy matters, is the main practical decision.

Frequently Asked Questions

What is an Erlenmeyer flask used for?

It is used to mix, swirl, heat, and store liquids, to hold solutions during titration, to prepare culture media, and to grow suspension cultures of microbes or cells, often on a shaker.

Why is an Erlenmeyer flask cone-shaped?

The wide flat base gives stability and surface area, and the narrowing sides and neck allow the liquid to be swirled with little spilling. The narrow neck also accepts stoppers or plugs and limits evaporation.

Can you measure accurately with an Erlenmeyer flask?

No. The printed markings are approximate. For accurate volumes, labs use volumetric glassware or a calibrated pipette instead.

Can you heat an Erlenmeyer flask?

Borosilicate glass flasks are made to tolerate heating, but limits and safe practice vary, and plastic flasks generally cannot be heated directly. Follow the manufacturer’s instructions and your institution’s safety procedures.

What is the difference between an Erlenmeyer flask and a beaker?

A beaker has straight sides and a wide opening, which makes it easy to pour and reach into but prone to spilling when swirled. An Erlenmeyer flask has sloping sides and a narrow neck, which suits swirling, covering, and heating.

What is a baffled flask?

It is an Erlenmeyer-style flask with ridges in the lower wall that disturb the liquid as it is shaken, increasing mixing and oxygen transfer. It is used for cultures that need a lot of aeration.