Standard Reference Method

Standard Reference Method

Standard Reference Method or SRM is a system modern brewers use to measure color intensity, roughly darkness, of a beer or malted grain. This method involves the use of spectrophotometry to assign a number of degrees SRM to light intensity.

The SRM number is defined as 10 times the absorbance of a sample at 430 nanometers measured through a .5-inch cell. The 430-nanometer wavelength corresponds to a deep blue light, and is the wavelength at which beers appear most different from each other.

The standard was adopted in 1950 by the American Society of Brewing Chemists as an objective measurement of color unburdened by the difficulties of the Lovibond system; the measurement of the color of a beer in degrees SRM and degrees Lovibond are approximately equal and in practice can be used interchangeably to evaluate the color of intensity of beer.

Degrees SRM are related to the current EBC standard by::mbox{EBC} = mbox{SRM} imes 1.97:mbox{SRM} = mbox{EBC} imes .508;as a rule of thumb, EBC is approximately twice SRM.

Note that an earlier version of EBC color was based on absorbance at 530 nanometers, which permitted no direct conversion between the two systems. However, if one assumes a linear log absorbance spectrum (the Linner hypothesis from the realm of caramel color), and knows the Linner Hue Index, ] H_L, the absorbances are related by:

:A_{430} = A_{530} imes 10^{H_{L}/10}

A formula for converting between the old EBC color value and SRM sometimes continues to appear in literature. It should not be used, as it is flawed and based on measurements which are no longer taken.

Color based on Standard Reference Method (SRM)

References

*"Dictionary of Beer", Ed: A. Webb, ISBN 1-85249-158-2
*"Home Brewing", Graham Wheeler, ISBN 1-85249-137-X


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Reference range — Reference ranges edit in: blood urine CSF feces In health related fields, a reference range or reference interval usually describes the variations of a measurement or value in healthy i …   Wikipedia

  • Reference ranges for blood tests — Reference ranges edit in: blood urine CSF feces Reference ranges for blood tests are sets of values used by a health professional to interpret a set of …   Wikipedia

  • Reference electrode — Reference electrodeis an electrode which has a stable and well known electrode potential.The high stability of the electrode potential is usually reached by employing a redox system with constant (buffered or saturated) concentrations of each… …   Wikipedia

  • Method of loci — The method of loci (plural of Latin locus for place or location), also called the memory palace, is a mnemonic device introduced in ancient Roman rhetorical treatises (in the anonymous Rhetorica ad Herennium, Cicero s De Oratore, and Quintilian s …   Wikipedia

  • method — The mode or manner or orderly sequence of events of a process or procedure. SEE ALSO: fixative, operation, procedure, stain, technique. [G. methodos; fr. meta, after, + hodos, way] Abell Kendall m. a …   Medical dictionary

  • Standard Written English — is an alphabetic, morphophonemic representation of the English language, and is the world’s most commonly used alphabetic code. It is used as the basis for handwriting, print, Braille, and Signed English. It is relatively transcendent of varying… …   Wikipedia

  • Standard illuminant — A standard illuminant is a profile or spectrum of visible light which is published in order to allow images or colors recorded under different lighting to be compared.CIE illuminantsThe International Commission on Illumination (usually… …   Wikipedia

  • Standard error (statistics) — For a value that is sampled with an unbiased normally distributed error, the above depicts the proportion of samples that would fall between 0, 1, 2, and 3 standard deviations above and below the actual value. The standard error is the standard… …   Wikipedia

  • standard — {{Roman}}I.{{/Roman}} noun 1 level of quality ADJECTIVE ▪ high ▪ low, poor ▪ certain, minimum ▪ Players have to be of a certain standard to compete in the tournament …   Collocations dictionary

  • reference group — The term reference group was coined by Herbert Hyman inArchives of Psychology (1942), to apply to the group against which an individual evaluates his or her own situation or conduct. Hyman distinguished between a membership group to which people… …   Dictionary of sociology

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”