Beer Quality: Color & Clarity

Welcome to Beer Quality: Color and Clarity led by distinguished professor Charles Bamforth, Ph.D. In this course, you will learn about beer color and how it impacts a consumer's perception of beer. Also discussed are the scientific factors affecting beer color and clarity. The methods of measuring and altering beer color are presented, as are ways to troubleshoot problems with beer color.

• Getting Started & Color/Clarity
• In this module, we begin discussing how beer color and clarity influences the consumer. We'll review some informal research that was conducted regarding consumer perception of beer based on clarity. If you clarify a beer, does it take anything away? We'll discuss this question.
• Measuring and Chemistry of Color
• In this module, we'll discuss color, some of the basic science behind it, and how humans perceive it. We'll review the Beer-Lambert law equation as well as well as the ASBC and EBC methods of measuring color and look at light absorbance of various beers. Then, we'll review methods and devices used to measure color and discuss what to consider when choosing a method. We'll go over the main source of color in most beers, the Maillard Reaction. And, you'll understand how the oxidation of polyphenols affects beer color, ways of adjusting beer color, and discuss what to do when your beer color is not what you were expecting.
• Turbidity Problems & Colloidal Stability
• In this module, we start our discussion regarding turbidity in beer and the role of bits in beer clarity. We'll discuss what invisible haze is and how it affects beer clarity, compare biological haze with non-biological haze, and compare and contrast chill haze with permanent haze. We'll also look at how we measure, interpret turbidity issues, discuss how bits and haze are measured, and touch on the role of microbiology in beer stability.
• Clarity and Stability & Turbidity
• In this module, we discuss how grist, hops, malting, and mashing influence beer clarity and stability. We'll also discuss how wort, fermentation, cold conditioning, filtration, stabilizers, and packaging influence clarity and stability. We'll also offer methods of troubleshooting turbidity and touch on beta-glucan, arabinoxylan, starch, oxalate, and dead bacteria. We'll also offer methods of troubleshooting turbidity involving protein, foam stability, and polyphenols.