#53 - A Scientific Approach to Coffee Freshness | Chahan Yeretzian | Expo Lectures 2018
Summary: Since the early days of the specialty coffee movement, freshness has been one of its central pillars. It is best defined as having its original unimpaired qualities and is often understood, in coffee, as freshly roasted, ground within a few days, immediately extracted and consumed. In spite of this pivotal role of freshness for high-quality coffee, the scientific measurement of freshness has been vague and elusive. In today’s recorded lecture, Chahan Yeretzian outlines two approaches. One is based on the degassing of the freshly roasted coffee - Chahan discusses the link between CO2 content and degassing to freshness, processing, and cup quality - while the other approach looks into the evolution of the aroma profile during storage. Related Links - Read the full transcript or view Chahan's slides on SCA News: https://scanews.coffee/podcast/53/a-scientific-approach-to-coffee-freshness-chahan-yeretzian-expo-lectures-2018/ - Listen to other episodes of the SCA Podcast: https://scanews.coffee/category/podcasts/sca-lectures-podcast/ - Learn more about the upcoming 2019 Lecture Series: https://www.worldofcoffee.org/ Subscribe to this podcast on your favorite app: - iTunes: www.apple.co/2sXdmSj - Stitcher: www.bit.ly/2JBJOk8 - Pocket Casts: www.bit.ly/2JBowTT - RadioPublic: www.bit.ly/2JCfeGY Table of Contents 0:00 Introduction 3:00 How freshness forms part of the specialty coffee story 9:00 How do we define freshness? 12:00 How to measure the freshness of roasted coffee through CO2 34:45 How does Co2 release affect processing and the cup 49:00 How to measure the freshness of roasted coffee through volatile aroma compound 1:06:00 Presentation conclusion Audience questions 1:10:15 Is flushing freshly roasted coffee bags with nitrogen a waste of money? 1:11:00 With different CO2 values from different roast values, which is more important: the absolute CO2 concentration or the percentage loss? 1:13:15 During the CO2 experiments, what purging testing through a GCMS was done to see they were getting any of the VOCs out, or is the weight is solely CO2? 1:15:45 Once a coffee’s temperature was dropped to reduce the CO2 release in the freezing experiments, were experiments done studying the what happens when temperature is increased again. 1:18:15 Outro
