Laboratory evaporating dishes: how can a sample be concentrated, dried or a dry residue recovered?

Indispensable in analytical chemistry and quality control alike, the evaporating dish lets you safely concentrate a solution, dry down an extract or recover a dry residue. Available in porcelain, borosilicate glass or stainless steel, these wide, shallow vessels maximise surface area and deliver uniform heat-up on a hotplate, over a Bunsen burner (depending on the material) or in an oven. A pouring spout, capacities from 30 to 300 mL, and compatibility with watch glasses streamline handling. A sample preparation staple, it also helps initiate crystallisation or set up a gravimetric determination.

What are the different types of evaporating dishes?

Three families coexist, each suited to specific heating regimes and chemistries.
• Vitrified porcelain: excellent resistance to thermal shock and high temperatures (up to approx. 1000 °C depending on model). Compatible with most acids (except HF). Hot strong bases can attack the glaze. Direct flame heating possible (Bunsen burner with wire gauze). Ideal for residue to dryness, fast evaporations and gravimetric determinations.
• Borosilicate glass: transparency for close visual control (boiling, crust formation). Heat on a hotplate or in an oven; avoid flame and thermal shock. Do not use with HF or hot concentrated bases. Perfect for gentle evaporation, crystallisation and volatile solvents.
• Stainless steel: robust and conductive, it speeds up heating on a hotplate or in a heated bath. Sensitive to chloride-containing media and some oxidising acids. Not suitable for HF. A good choice for routines and field work, where mechanical strength is paramount.
Selection criteria: nature of the medium (solvent, pH, oxidants), available heating method, working volume and geometry (wide base, pouring spout), compatibility with lid/watch glass, cleanliness requirements (risk of metallic contamination) and durability.

Type	Recommended heating	Applications
Porcelain	Bunsen burner (with wire gauze) or hotplate	Residue to dryness, gravimetric determinations
Glass (boro)	Hotplate/oven, gradual heating	Gentle evaporation, crystallisation
Stainless steel	Hotplate, heated bath	Routine work, robustness, field work

In which fields and applications is an evaporating dish used?

Evaporating dishes are ubiquitous in quality control, R&D and teaching. In environmental testing: concentrating extracts, determining dry residue, pre-evaporation prior to ashing. In food and beverage: measuring dry extract or dissolved solids. In pharmaceutical and cosmetic: sample preparation, removal of residual solvents before chromatographic analyses. In chemistry: concentrating intermediates, evaporation in a water bath or on a hotplate. In life sciences: drying extracts, recovering the active ingredient after controlled evaporation.

The different types of evaporating dishes available

Frequently asked questions about evaporating dishes

Which material should I choose for my application?
Porcelain for high temperatures and gravimetric analysis, glass for visual control/gentle evaporation, stainless steel for robustness. Check chemical compatibility before use.

Can an evaporating dish be heated directly over a flame?
Yes for porcelain (on a wire gauze) and, with care, for stainless steel. Avoid direct flame with borosilicate glass to reduce the risk of thermal shock.

How can I minimise splashing and foaming?
Heat gradually, use a watch glass as a partial cover and, if compatible, add anti-bumping granules/boiling chips. Do not fill the working volume to 100%.

Does a glass dish withstand strong bases?
Borosilicate is sensitive to hot, concentrated bases. Prefer porcelain or another inert material selected for the pH and temperature.

And with hydrofluoric acid (HF)?
Avoid glass, porcelain and stainless steel. Use suitable vessels such as PTFE and follow HF-specific safety procedures.

What volumes should I choose?
Approximately 30 to 300 mL. Choose a volume that leaves headspace (30–50%) to limit boil-overs and optimise the evaporation surface area.

Care tips?
Use appropriate chemical cleaning; no abrasives on glass. Gentle descaling/light acid cleaning on porcelain if needed. Rinse and dry stainless steel thoroughly to limit corrosion.