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Color                                                                                                                     IBU






                    The color of food and beverages is so important that it’s been   Method (SRM) while the Europeans use the European Brewery   Bitterness is one of the major flavor components in beer and is   bitterness in beer is by measuring the iso-alpha acids (IAA). This
                    said that people “eat with the eyes” and their palates. If a food   Convention (EBC). To convert from SRM to EBC, use the formula:   used to balance out the sweetness from the malts. The   process requires a different solvent extraction and measurement
                    tastes bad, someone will probably not eat it again; however, if it   EBC = SRM x 1.97. The higher the SRM value, the darker the   bitterness from the hops is caused by alpha acids, which are   of absorbance at 255 nm. Results are reported in units of mg/L
                    doesn’t look good it may never be tasted at all.   beer.                                                                  extracted from the hops flower during the boil process. The   or parts per million (weight/volume). There can be some
                    The color of beer can be measured with a UV-Visible   The second method, which provides more color information, is        alpha acids are converted to iso-alpha acids and provide the   differences between the results of these two methods.
                    spectrophotometer. There are two methods for measuring the   the CIELAB method, also called Tristimulus Analysis. This method   bitter taste. Hops also add their own aroma and flavor to the   The European Bitterness Units (EBU) scale as defined by the
                    color of beer depending on how much information is required.   measures 81 points at 5 nm increments from 380 nm to 780 nm.   beer as well as provide antibacterial and preservative qualities.   European Brewery Convention (EBC) has a different process
                    The first method is a single point measurement at 430 nm with   The color vision theory is based on three opponent pairs for the   The International Bitterness Units (IBU) scale was created to   than the IBU scale of American Society of Brewing Chemists
                    a 1 nm bandwidth. This method has been reported to provide   L*a*b* values where the “L” is the luminosity, “a” is the red to   measure the perceived bitterness of beer. The method requires a   (ASBC).
                    92% of the information on beer color. Americans and   green color component, and “b” is the yellow to blue color          solvent extraction followed by measurement at 275 nm with a   For hops analysis by specific compound type, see “Section 2: Top
                    Europeans preform the same measurement, but the color   component. This type of measurement requires optional             UV-Visible spectrophotometer. Another method for measuring   Beer Analyses – Hop Degradation Analysis – Alpha Acids.”
                    schemes are different. Americans use the Standard Reference   Shimadzu color software.


                                                                                               L*=100
                                                                                               (white)
                                                                                        b*
                                                                                      yellowish


                                                                               -α*                             a*
                                                                             greenish                        reddish

                                                                                                                                                                                   Shimadzu UV-1800 for
                                                                                                       -b*
                                                                                                      blueish                                                                      measurement of beer bitterness
                                                                                                                                                                                   and alcohol content
                                                                                               L*=0
                                                                                               (black)

                                                                                   CIELAB Color Space for Beer Analysis
                          Shimadzu UV-1800 for
                          measurement of beer color


































                                                                                                                                                                                         Shimadzu’s Total Support for Beer Analysis
             6                                                                                                                                                                                                                 Analytical and Testing Instruments for Beer  7
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