Paste commonly denotes a soft, cohesive, often spreadable substance and the actions associated with placing or joining material. Physically, a paste is a semi-solid mixture of a liquid and finely divided solids that yields a viscous, plastic consistency: it can be spread, shaped or extruded. As a verb, to paste means to affix, insert or join one element to another; in computing it denotes placing previously copied data from a clipboard into a document or field.

Composition and properties

Pastes typically combine binders, solvents or water, fillers and sometimes active additives. Their behavior depends on particle size, solid content, rheology (flow characteristics), drying or curing mechanisms, and temperature sensitivity. Some pastes are waterborne and reversible, others cure chemically to form permanent bonds. Key properties include tack (initial stickiness), cohesion (internal strength) and viscosity.

Common types and examples

  • Adhesive pastes: starch-based pastes, animal glues and synthetic polymer pastes used in bookbinding, wallpapering and crafts.
  • Culinary pastes: tomato paste, curry pastes, nut and seed pastes, miso and concentrated fruit pastes used to concentrate flavor or act as a base ingredient.
  • Industrial pastes: solder paste for electronics, ceramic pastes for shaping and glazing, printing pastes for textiles and inks.
  • Specialty pastes: dental impression materials, restorative pastes in conservation, and cosmetic or pharmaceutical formulations.

History and uses

Paste-like substances and techniques have ancient origins: early adhesives from starch, hide or fish glue were used in woodworking and manuscript production, while concentrated food pastes aided storage and transport. Modern chemistry expanded formulations for specific tasks—electronic assembly, high-temperature sealing and food processing.

Practical considerations

Choosing a paste requires attention to performance, compatibility and safety. Food pastes demand hygiene and preservation; solder pastes require temperature control and limited shelf life; conservation pastes prioritize reversibility. Pastes differ from gels, creams and purees mainly by higher solid content and intended function. Proper storage, handling and disposal follow industry or regulatory guidance for each type.