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Measuring Color - Beer Color, specifically:
Lovibond Color
In the United States, color is expressed in terms of the Standard Research Method (SRM) values set by the ASBC or in �Lovibond, an older method of visual measurement upon which SRM is based (the two measurements are essentially equivalent). In European lot analyses, color may be measured according to a visual method developed by the European Brewing Convention (expressed as EBC units). The formula �EBC = (�L X 2.65) - 1.2 gives a reasonably accurate translation to �Lovibond values. European maltsters are considering still another switch to a different method of measuring color; however, until the new method is accepted, the EBC-to-Lovibond conversion method will generally still apply.
Lovibond is a standard scale for the measurement of grain wort and beer color. A particular sample is characterized with a Lovibond rating by comparing it to a standard liquid reference sample. Malt is assigned a Lovibond rating by producing a sample wort from a single malt grist and comparing the result to the standard color reference samples.
There has always been a strong preference in brewing for visual units to be used for the evaluation and determination of beer color. There are many reasons for this, not the least of which is the fact that the classic beer styles are defined in part by definite visual images concerning what is appropriate. Beer and wort color traditionally have been measured visually, and early on the Lovibond (degL) scale was adopted as a standard. This scale consists of a well-defined set of color samples that are used for comparison. A visual match with a beer or wort sample defines the degL of the sample.
In the 1950s it was discovered that for pale beers absorbance so measured was essentially proportional to visual units like the Lovibond scale. In 1958, the American Society of Brewing Chemists proposed that the absorbance of beer in a 1/2" ID jar using a monochromatic light with a wavelength of 430 nm be used; the procedure was called the Standard Reference Method (SRM). They proposed a correction factor of 10 so the numbers reported would match up with the Lovibond scale. Commercial beer brewed at this time was almost always below 4 Lov., and hence SRM became viewed as an equivalent of Lov. However, as beers became darker, the relationship between the spectrophotometric method and the visual lovibond scale diverges and the factgor of 10 no longer applies. Typically the approach has been to develop new in-house correction factors for each of the darker brews.
Lovibond and SRM can be used interchangeably ... unless beer color moves into the amber regime at which time the relationships between visual and spectrophotometric units start to diverge sharply. Large commercial breweries continue to use spectrophotometry for color determination even for the amber and dark beers they started brewing in recent years. Their approach has typically been to develop new in-house correction factors for each of their brews which allows them to match up absorbance with the Lovibond scale within the range of variations seen in production. So - homebrew is in hand - your looking at it admirably and wondering what color is it. You mean you don't have a spectrophotometer in your basement?? Don't despair!! For normal color determination, such as needed in recipe design and judging your homebrews, a little dohingy called the Davison Color Chart has proven to be quite satisfactory. This chart is actually a transparent film strip tinted at ten beer color increments between yellow (3 Lov.) to brown (19 Lov.).
COLOR LOVIBOND MEASUREMENT Light Yellow 2.0-3.0 Medium Yellow 3.0 - 4.5 Deep Straw/Gold 4.5 - 6.0 Deep Gold 6.0 - 7.5 Light Amber 7.5 - 9.0 Copper 9.0 - 11.0 Red/Brown 11 - 14 Light Brown 14 - 17 Medium Brown 17 - 20 Light Black 20 - 25 Black >25 It should be noted that the visual units start becoming highly suspect once the full black regime is reached. For example, it is reported that highly qualified national judges have been unable to correctly distinguish beers at 40, 50, and 60 degrees Lovibond.
A rule sometimes used by homebrewers is that the color contributed by a malt is equal to its concentration in pounds per gallon times its color rating in degL. For pale beers this rule can give reasonable results. For example, 10 pounds of pale malt with color 1.6 degL in five gallons should produce a beer whose color is near 1.6 x 10/5 = 3.2degL. For darker colored beers, this rule can give erratic results. Beers with an actual degL of 23 will be predicted at 70+ using the simple degL/lb/gal calculation. There is a software available with color calculator that is reported to be fairly accurate and the recipe printout will show you the individual color contribution of each component. The program reportedly takes into account the color rating of the components, boil/steep time, boil size/batch size, and spits out a number that matches reality as represented by the Davison Chart
The Lovibond measurement for color is also used in the honey industry.
Also, see this page called:
"Beer color - how it's defined what makes it, what impacts it, and how to predict it ...."And, The Lovibond Beer Color Database
Additional Flavoring
See "Technical Information About Honey", and especially the "Honey In Beer" article [PDF]
Brewing with Honey - Real Beer Page: Search Results: "Honey"
Brewing with Chocolate - Real Beer Page: Search Results: "Chocolate"
Daril-Bill - 06/26/05 - (daril@darilbrothers.com)
