Bloom (test)

Bloom is a test to measure the strength of a gel or gelatin. The test was originally developed and patented in 1925 by Oscar T. Bloom.[1] The test determines the weight in grams needed by a specified plunger (normally with a diameter of 0.5 inch) to depress the surface of the gel by 4 mm without breaking it at a specified temperature.[2] The number of grams is called the Bloom value, and most gelatins are between 30 and 300 g Bloom. The higher a Bloom value, the higher the melting and gelling points of a gel, and the shorter its gelling times.[2] This method is most often used on soft gels. To perform the Bloom test on gelatin, a 6.67% gelatin solution is kept for 17–18 hours at 10 °C prior to being tested.

For other uses, see Bloom (disambiguation).

Various gelatins are categorized as "low Bloom", "medium Bloom", or "high Bloom", but there are not universally defined specific values for these subranges. Gelatin is a biopolymer material composed of polypeptide chains of varying length. The longer the chain, the higher the Bloom number:[3]

Gelatin classess
Category Bloom number Average molecular mass
Low Bloom 50–125 20,000–25,000
Medium Bloom 175–225 40,000–50,000
High Bloom 225–325 50,000–100,000

See also

References
  1. "US1540979 Machine for testing jelly strength of glues, gelatins, and the like". Google Patents. Retrieved 1 September 2016.
  2. Schrieber, Reinhard; Gareis, Herbert. Gelatine Handbook: Theory and Industrial Practice. Wiley. ISBN 978-3-527-61097-6.
  3. "Gelatins—product information sheet" (PDF). Sigma-Aldrich. Retrieved 24 August 2017.
  • Phillips, Glyn O.; Williams, Peter A. (2000). "6.3.1. Bloom strength—standard method for characterizing gel strength". Handbook of Hydrocolloids. Taylor & Francis. ISBN 9780849308505.

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