1. Technical Brewing Beyond Lovibond — Understanding Beer Color Bob Hansen - Technical Services Manager 4.18.08

2. 1 Color and Light What is light? Electromagnetic wave spectrum. []. Retrieved April 13, 2008, from Encyclopædia Britannica Online: http://www.britannica.com/eb/art-70892 Electromagnetic wave spectrum. []. Retrieved April 13, 2008, from Encyclopædia Britannica Online: http://www.britannica.com/eb/art-70892

3. 2 Color and Light What is color? What causes color?

4. 3 Visible spectrum of light

5. 4 Reflection, Absorption and Transmittance Colored light can come to the eyes in one of three ways: Primary Source Directly from a light source Secondary Sources Light reflected off an object Light transmitted though an object For Secondary Sources, Interaction of Primary Light and Secondary Source is Very Important

6. 5 Beer’s color is Transmitted White light is transformed to yellows as blues are absorbed. BEERBEER BEERBEER

7. 6 Measuring beer color Many means have been used to measure and predict a beers color: Visually-the original and obvious way Using a machine Using a more expensive machine

8. 7 Measuring Transmitted Light P0P0 P0P0 P P Transmittance = P/ P 0

9. 8 Measuring Transmitted Light Transmittance measures the % age of light reaching the eye. As the photo response in our eye is proportional to the light it receives, transmittance represents most closely light or color intensity.

10. 9 Absorbance vs. Transmittance Absorbance = Log 10 1/T Absorbance = Log 10 1/(P/P 0 ) Absorbance = Log 10 (P 0/ P) Beers Law A= eBC

11. 10 Absorbance vs. Transmittance Absorbance = Log 10 1/T

12. 11 Wort preparation for color - Measured using a mash with a grain bill of 50 grams/ 450 grams (11.1% ) - Similar concentration to brewers rule of thumb, 1 lb/gallon (10.7%) - Specialty malts mashed with base malt as needed - Corresponds to a wort of roughly 8 Plato or 1.032 - Beer / Wort normally diluted to get absorbance below 2.0

13. 12 Transmission Spectrum of Specialty malts

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16. 15 A whiter shade of pale? 2 SRM

17. 16 A whiter shade of pale?

18. 17 Orange or Tan 10 SRM

19. 18 Orange or Tan

20. 19 Red or Brown-20 SRM

21. 20 Red or Brown- 20 SRM

22. 21 Mahogany or Black-30 SRM

23. 22 Mahogany or Black-30 SRM

24. 23 Spectrum of Same Color Worts

25. 24 Caramel Malt Black Malt 10 SRMOrangeTan 20 SRMRedBrown 30 SRMMahoganyBlack Summary-Specialty Malt Color

26. 25 Summary-formulating for color A beers color is caused by the selective transmission of light Light source, path length and concentration are important to measuring and viewing a beers color Absorption of light by different classes of malt is mostly equivalent across the spectrum of visible light Current SRM is good for measuring batch to batch variability within the same recipe Current SRM color rating is ineffective for describing the actual color of darker colored beers.

27. 26 Summary-formulating for color Full spectrum analysis can give a truer picture of beer color. At equivalent SRM the color from different malts within the same class will be the same, though flavor may vary. True perceived beer color could be predicted from recipe. Dark roasted malts absorb more strongly across the spectrum, leading to darker beers and browner tones at equivalent SRM. Tools could be developed to be both predictive and descriptive of true beer color.

28. 27 Questions?

29. Thank You!