By Emma Sage, Coffee Science Manager, SCA
(with special thanks to Randy Pope and Ted Lingle for their contributions)
Throughout modern coffee history, one consistently recognized method has prevailed that determines a properly brewed cup of coffee. Of course, this is the brewing control chart. This tool takes something as subjective as the desired taste profile and gives us a quantifiable method to track the consistency of each brew. Despite some modern criticisms of this method, the tool remains a trusted staple of the specialty coffee industry, and continues to help many coffee professionals understand strength and extraction. What is perhaps most impressive about this invention is its longevity. In fact, the work on this fundamental tool began in the 1950’s and was conducted through the 1970’s by an establishment named the Coffee Brewing Institute (CBI). In fact, the CBI laid a majority of the cornerstone brewing concepts we still utilize today to brew fresh, tasty specialty coffee.
If you can imagine, in the 1950’s there were many opinions in the coffee industry on what constituted a “good cup” of brewed coffee, but there was very little research to support those opinions. As a result, the National Coffee Association commissioned a food technology Ph.D. from the Massachusetts Institute of Technology, Professor Earl E. Lockhart, to conduct a series of studies to determine how best to define “coffee quality.” The continuation of this work led to the foundation of a suite of brewing essentials. This research resulted in not only a formula for brewing coffee that can deliver a balance of strength and extraction, but extended to equipment cleanliness, water, temperature, grind, and time. These are the same fundamental concepts that live in SCA’s Coffee Brewing Handbook and are integrated into all of SCA’s current programs. Let us take the opportunity to look back in time and understand how these concepts came to set the stage for specialty coffee.
Initiated by the National Coffee Association and affiliated with the Pan American Coffee Bureau, the CBI was formed around 1952, and marked a new focus on industry research and customer preferences for coffee in the United States. Dr. Earl E. Lockhart was the institute’s first director. Dr. Lockhart has been credited for his leadership role in conducting some of the most advanced coffee research at the time, including the measurement of “soluble solids” in coffee as an index of quality. Much of the work conducted by the CBI was towards determining the optimal methodology to brew good coffee, which led to the distribution of many recommendations, such as the brewing essentials. This focus on the consumer led the Institute to realize that the majority of complaints around coffee were the direct result of improper brewing methods.
As more coffee professionals became interested in the science of coffee brewing, the CBI instituted formal industry training programs that led to the development of the Coffee Brewing Center (CBC), which replaced the CBI around 1963 and relocated to New York City. The CBC, directed by Gene Loughery and later followed by Ken Burgess, continued their work in the food service sector to promote the brewing standards created by the CBI in concert with the Midwest Research Institute in Kansas City, Missouri. The CBC operated weekly classes well into the late 1960’s and was funded in large part by coffee producing countries, notably Brazil and Colombia. Eventually, the funding dried up, and by the mid 1970’s the CBC had closed its doors.
The Coffee Brewing Institute, in its tenure, published a variety of reports in trade journals as well as independently and in scientific literature. Research topics included brewing essentials, water hardness, brewing temperature (where do you think 195-205°F came from?), holding time and temperature, grind size recommendations for different brewing methods, brew strength and concentration, time and extraction, filtration devices and baskets, and brewing equipment quality. The CBC was the developer of the Golden Cup Award program, which was designed to promote proper brewing technique at the restaurant level and provided training to the foodservice trade.
While most of the CBI’s original research had been published in pamphlet form, their pamphlets became hard to find and remained virtually unavailable until 1994, when SCA published the Coffee Brewers Handbook that covered most of the important studies relating to coffee brewing from the original work conducted by Professor Lockhart. This handbook has fueled many SCA products and education programs since, and informed multiple waves of coffee professionals who have engaged with SCA. These programs all stand on the core brewing essentials, now listed in the Brewing Handbook. These include the correct coffee-to-water ratio, brew time, contact time, water temperature and quality, brewing method, and filtration method. Current SCA programs influenced by the CBI and CBC include not only the Gold Cup Award and Technician Certificate, but also the Home Brewer Certification program.
Although there were many useful publications from the CBI/CBC, one of the most valuable assets they provided to the coffee brewing industry was perhaps the Coffee Brewing Control Chart. The relationship of strength, extraction, and brew formula gave a quantifiable approach to verifying the consistency of the brewing process. The gold cup ratio was designed by the CBI to fit that “ideal” extraction and strength zone. Through sensory evaluation tests, a range of formulas were developed. Beverages were analyzed for soluble concentration (strength) to determine the percentage of the beverage that was the soluble material from coffee. A range of strength from 1.15 – 1.35 % coffee soluble material in the beverage was determined to be the most enjoyable through CBI testing. Extraction (yield) from the grounds was also analyzed. The desirable extraction limits were determined to be within a range of 18 – 22 % of the original weight used in the brew. The development of the Coffee Brewing Control Chart gave us a clear and understandable tool for plotting or recording the consistency of the brewing process. This work laid the foundation for brewing ‘good coffee’ and has since allowed us to have this discussion amongst an educated coffee community.
From the research conducted by the CBC and CBI, the specialty coffee industry was enabled to brew fresh, appropriately ground and extracted coffee. Dr. Lockhart and others laid the foundation for many existing SCA programs. Despite recent advances in brewing knowledge technology, these cornerstone concepts have prevailed and continue to educate our community. Let us take this opportunity to appreciate our coffee forefathers for enabling our industry. After all, a large part of recognizing and promoting specialty coffee is, in fact, dependent on the ability to brew a ‘good’ cup of coffee.
Emma Sage is the Coffee Science Manager for the Specialty Coffee Association. Before moving into the coffee industry, she completed degrees in ecology and botany, and dabbled in the wine industry. She enjoys learning all there is to know about the science of coffee (and more importantly, sharing it with you).
With special thanks to Randy Pope and Ted Lingle for their contributions.