Roasting Trends Not Good for Low Acid Coffee Drinkers
In case you have just joined the conversation, longer roasts are needed to reduce Chlorogenic acid and produce a low acid coffee. The primary reason is that the temperature and the duration of the application of heat to the coffee has to be sufficient and sustained for a long enough period of time to degrade the levels of Chlorogenic acid.
However, modern roast profiles are not designed to achieve those temperatures and sustained levels of heat. Did you know that the trend in coffee roasting world-wide is headed to shorter, earlier, and higher temperature roasts? Ironically, roasts are getting hotter to speed up production and accelerate development, but the overall finished roast temperature is declining, which results in coffees retaining much of their acidity.
How is it that roasters can use higher temperatures, yet at the same time the roasts are getting cooler? This answer requires a more detailed look.
When roasting coffee, roasters must manage the temperature of the air in the roasting drum chamber and the actual temperature of the coffee bean. In some instances, the differential between the air temperature and the actual temperature of the coffee bean can differ by more than 100ºF.
In using a very aggressive application of high heat and high start temperatures, modern roast profiles are designed to bring the coffee to the desired drop temperature in order to finish the roast very quickly. However, modern profiles also call for dropping the coffee earlier in the roast process, as the trend in coffee is light roasts with more “fanciful” flavor notes.
Therefore, since the roast profile is designed to start at a higher air temperature and finish at a lower bean temperature, which is a lighter roast, the overall roast duration is dramatically reduced. As a result, modern roast profiles fail to bring the coffee beans to a sufficient temperature and duration to begin to minimize the presence of Chlorogenic acid in any significant way.
That means the odds are that your next cup of coffee will be high in acid!