Taste Evaluation of Green Coffee Bean Samples Prior to Purchase & Use
Presenter: Michael Sivetz, from his SCAA presentation
With so many new small retail and wholesale roasters coming into the trade in the late 1980’s and early 1990’s, it has become pertinent to review the factors influencing green coffee bean purchasing decisions.
The small roaster who buys 10, 20 or 30 bags at a time, or even 50 to 100 bags at a time, bases his decisions on factors quite different from the large roasters who buy container loads (250 bags) or ship loads. These large roasters mass package cans, and now valve bags, or pouches of R&G coffee. They look to lowest prices first and quality second (end product is stale). It is intended here to discuss how and why buying decisions are arrived at and how they should be arrived at, and not to discuss the careless methods often used by both new and old roasters.
The buyer has certain ideas about what he would like to purchase at a particular time. The buyer’s choices are limited to those green coffee brokers he is currently using, presumably with stocks within a few hundred miles of his roaster. The stocks available maynot be as broad as desired, have the quality levels desired, or the amounts sought.
So, the ability to fulfill one’s needs may require larger purchases of a particular type so that inventories will carry over into periods when those types of coffees are not available. Or the prospective buyer, may have to go to brokers located several thousand miles away. Perhaps a substitute coffee may have to be used. Price per pound may be a consideration, but it is usually secondary to quality for most small roasting operations, depending on their competitive market.
In the USA, unfortunately, most green coffee imports in the past have been oriented to volume, and to the standards of large buyers like General Foods or Folger, who are price oriented. Until recently, very few green coffee brokers took the time and effort to go to growing countries to seek out "better than average" quality prepared green coffee beans.
The local small roaster is also pressured by his customers to get dozens of green coffees from various countries, under the false impression that each source will taste different. This is an unfortunate idea, that must be controlled and the buyer educated to the fact that coffee qualities are not designated by national/political boundaries. For example, one can take high grown coffees with good "washed" preparation and patio drying from Colombia, Central America and even from Kenya, Tanzania or Zimbabwe, and neither the public nor most small roasters could tell any significant taste difference. What is being dealt with is psychological, and not factual.
In my view, coffees from Kona for example, carry a high price (like $5/lb), not because they are better tasting than Colombian Supremos, but because there are only 20,000 bags produced per year, with highcost of labor, and hype related to nostalgia of palms, grass skirts and romanticism. Based on green coffee quality alone, most Kona coffees today are not even as good as-a good Colombian coffee, and are largely blended off with $1/lb Colombians at a 10% level and are sold as Hawaiian "blend" by the exploiters. In so far as green beans from the other islands of Hawaii, those beans, in many cases, are tainted by Rioy taste, which most buyers will not use.
Knowing the origin of the green coffee beans, is only the beginning of a long list of properties needed to be known about the coffee beans being considered for purchase. Although, history and tradition can be important factors in the purchase of this agricultural commodity; in the final analysis, it is the roasted bean taste that finalizes the purchase decision. There are so many intervening factors that can alter a potentially sound choice, e.g. weather, processing, politics, age, storage, shipping conditions, diseases, etc.
To control the quality of your purchases, you must always get a representative green coffee bean sample for your own roasting and taste evaluation. What the broker tells you is secondary.
THE BROAD PICTURE
The more one knows about the history of coffee growth, species, processing methods, current events, trade information, etc., the better equipped one is to have insight into coffee buying. For example, with two broad statements, one can discount 2/3 of world production as not being suitable for "gourmet" quality coffees.
Namely, Brazils which are harsh non-aromatic, low yielding coffees, are of no interest. There are a few limited production Brazilian coffees that are excellent, but they are exceptions and in any case these are very difficult to obtain. Robustas are the other 1/3 of world production which beans have a burnt rubbery taste, and usually wind up in the manufacture of instant coffees or are blended in substantial amounts in Hotel & Institutional coffees in the USA. Ironically, in France, the culinary nation, politics has dictated about 75% Robusta use.
Of the 1/3 balance of exports, are coffees referred to as mild . Most of these are "washed" beans, but some like Sumatra are naturally dried in the cherry. All these "milds" are not of the same quality. For example, Mexican coffees, have a characteristic taste that is not desirable, so that could discount 4 million (60 Kg) bags a year from the 1/3 world exports of 25 million bags. Half the milds grown in Central America, are not high grown, so that could be another 4 million bags of thinner quality beans. The rapid growth in the use of mechanical drying in Central America and elsewhere, as carried out, has a down-grading effect on coffee taste quality, and that can be another 4 million bags.
Processing damage can occur from the time the ripe cherry is picked until it is wet processed. For example, fermentation, rotting, mold growth, over-heating, improper storage and handling, droughts, excessive rains, diseases, pestilence, labor shortages, civil unrest, poor infrastructure (roads), excessive taxation, lack of capital, etc.
Often mechanical drying of the beans results in product quality inferior to patio drying. Many "beneficios" do not have complete nor up to date maintained machinery for removing defects, for bean size classification, for bean shape classification, cleaning out foreign matter, etc. Many "beneficios" do not have the silos and transport machinery to prepare 250 bag uniform lots. This is a most serious deficiency because, if all 250 bags are not uniform, how do you get a uniform sample?
If a "lot" of coffee beans (250 bags) is tainted with mold, fermented taste, Rioiness, or foreign contamination, how much taint is there in each bag, each pound?
Labor wages are very low in the coffee growing countries, and often theft occurs by removing all or part of wholesome export quality beans from a bag and substituting reject coffee beans. The outer bag stenciling and appearance are normal, but the contents are not. Coffee beans have been known to be dyed green, because, that gives a better new crop appearance. Stones and foreign matter have been placed in green coffee bags, as good beans are stolen.
In many countries, notably Colombia, there is an astonishingly little amount of tasting done. Further, when tasting is done, it is done by people who have little understanding of what the consuming country buyer wants; reject low grade "dirty" tasting beans stay and are used in the growing countries, by the public.
Misrepresentation and theft are not just in the growing country, but occur in the consuming countries, e.g. green coffee brokers are often less than candid about what they are selling, and are prone to take advantage of the new roaster. Also there are strict sampling standards for 250 bag lots of coffee shipments, requiring taking samples from 10% of the bags at random, examining these samples relative to each other, and using the composite for sales samples. Needless to say this is hard drudge-like work, which is often not done properly or at all. The discovery of a non-uniform lot of bags, is a devastating situation for all concerned.
WHAT TO LOOK FOR
I feel most comfortable and safe with using "milds" from the traditionally sound producing countries whose general product is about 1 million bags/year or more, and to select their best. For example, a safe selection can be Colombian Supremos as opposed to Excelsos.
This does not mean that a problem won’t occur in such a selection, it only means that a problem is less likely. As good as Colombian coffee beans and bagged shipments can be in general, I personally have run into various deficiencies. For example, some shipments will taste better than others. Some shipments will have too many defects. When I asked the Colombian Federation management about this specific problem, they said they did not control the quality of what was exported by brokers. I’ve purchased coffee from Huila, and gotten beans from Medellin. The moistures on Colombian beans invariably run higher than from other countries, e.g. 13 to 14%.
I look for a green bean color. Jade color is ideal, but seldom obtained. Faded green to gray colors mean that some deterioration has occurred in the shipment. A gray color means serious quality deterioration, e.g. over heated and prolonged storage.
A non-uniform bean appearance is an indication of poor preparation, and/or blending of different lots of beans. If this has occurred, it will reveal itself even more after the beans are roasted. Non-uniform bean sizes and shapes show a lackof proper preparation. Presence of many defects, definitely shows a coffee that has not been "benefacted". Many black beans will give a "dirty" taste, resulting in a low grade coffee. Many white beans are not as bad as black beans, but white beans are defects that weaken flavor.
If I have traveled in the country of origin of the beans purchased, I can sometimes relate conditions there with green bean product quality. An axiom worth remembering, is that if the country is having political, economic, or climatic problems, this will reveal itself in a lower grade quality of exports.
So, it pays to keep abreast of droughts, rain storms, revolutions, executions, oppressive administrations, excessive taxation, floods, volcano eruptions, and inflation.
Green coffee bean shipments from countries with large stocks, can often result in receipt of faded poor tasting lots.
When Colombia applies excessive export taxes, smuggling occurs. Although these could be "good" buys, there is always an element of risk in quality and quantity.
There are always "new" suppliers from the coffee growing countries with "good" deals. These buys are usually very risky . It is safer to deal with established importers who are on USA soil and with whom you can have recourse on any unsatisfactory purchases.
Smell the green beans. Examine their appearance for good green color, uniform size, shape & color. There should be no defects. Are the roast bean colors uniform? If not, that is an indication that the batch is non-uniform. The prevalence of lighter color beans after roasting means that immature beans are present. This results in a weaker, poorer and less uniform taste.
Always compare the freshly roasted sample to acomparable standard of your choice, e.g. last buy. Observe cup strength using the standard beverage preparation method. Some top quality beans can be 10 to 20% stronger than other good quality beans. On the other hand, poorer quality beans can be 20 to 30% weaker than other good quality beans.
The tasting should be done in aquiet, clean, pleasant environment free of distractions. It is essential to keep at least 1/4 lb. of the green bean sample until the actual bags arrive to confirm that the bagged coffee is the same as the sample furnished and taste tested.
WHAT REAL CUPPING IS
There is a tendency to believe that "cupping" is an isolated academic examination of the taste and aroma of green or roast coffee samples. In general it is "THE TEST" that helps one make the decision to buy or not to buy an offering. In the case where there is a production problem, taste testing can often pin point the start/end and scope of a taste variation, associated either with the raw commodity or with the processing of that commodity.
Therefore taste-testing encompasses a personal capability of tasting sensitivity combined with other technical knowledge about the coffee’s processing conditions. For example, one might be able to discriminate between the material and the process as the source of variation The ability to discriminate can translate either into solving a quality variation problem and/or upgrading the quality of the finished product.
Since there are many types of coffees, and even more modes of preparation, the ability to see into these circumstances becomes a valuable skill acquired over time.
The point is that "CUPPING" abilities and skills are largely related to real life circumstances. Each experience punctuates our memory about that "problem" with that taste.
I shall attempt to illustrate this with several examples:
Getting started is hard. But nature has given each of us an exceptionally sensitive nose andtongue, wherein we can taste minute as well as gross differences in our coffee beverages.
ANECDOTAL RELATIONS of TASTE to CIRCUMSTANCES
TASTE TESTING PROCEDURES: Traditional Green Coffee Broker vs. Gourmet Roaster
Traditional green coffee seller/buyer beverage preparations leave a great deal to be desired relativeto gourmet coffee consumer preparations.
It is my opinion and practice, to not use the techniques of the traditional green bean buyer, for several reasons:
GOURMET COFFEE TASTING PROCEDURES
Today in the 1990’s we have a broader selection of beans, degrees of roasts, fineness of grinds and cultural uses than ever before. We are not limited to the canned, stale, lightly roasted, or coarsely ground commercial coffees.
TASTING & THE CHEMISTRY OF COFFEE AROMAS & FLAVORS
With the growth of coffee retailing and roasting, those who do not have a chemical education, in regards to coffee, will find it difficult to appreciate the chemistry of roasting, the chemical compositions of aromas, and the chemical and physical changes and contents of the bean, grounds and beverages.
I will simply illustrate this point as follows:
In 1956, when gas chromatic analysis was in its infancy, I contracted Professor Zlatkis of the University of Houston to do analyses of the coffee aromas we were collecting at the Folger roasting and instant plant in Houston. We were exposed to one of the marvels of a science that was only beginning.
We took the condensed aromas from ice water traps, dry ice traps (-760C), and liquid nitrogen traps (-273 0 C), for gas chromatic analysis. In such analyses, an absorbent column slowly releases the individual components of aroma as an inert purge gas passes over the absorbent.
By smelling each component as it was purged, we could appreciate its contribution to the overall aroma of coffee. Many of these components were very volatile and unstable, so the elapsed time overall was critical to getting a genuine impression. We could smell acet-aldehyde, acetone, ethyl-ester, propyl-aldehyde, diacetal, acetic acid, etc. Many of these mentioned represented large percentages of the aroma. However, their sensing threshold concentrations were relatively high. There were other aromatics which were much more potent to our senses, a thousand fold, e.g. di-methyl sulfide.
We not only confirmed these chemicals by smell but also by mass spectroscopy , which combined with gas chromatography formed a very sophisticated analytical procedure. Subsequently other investigators at the SW Research Institute in San Antonio, Texas, the QMC research laboratories in Massachusetts, and by the Tenco Division of Coca Cola Corporation. expanded these studies and reported around 100 major chemicals and around 300 minor chemicals in the coffee aroma. Needless to say the range of concentrations found on the numerous individual chemicals varied with green bean type, source, processing as green, processing to roasted, degree of roast, etc. As chemists who recognize many of these components individually, it was very educational and impressive to relate and identify each in the complex mixtures evolved.
To this extent a chemist, chemical engineer, or food technologist, is better able to see the chemical compositions that make up coffee aroma
Also related to this, was a program in the 1950’s and early 60’s to aromatize instant coffees. I had the opportunity to add back many of these components to coffee extracts and powders and had personal taste experiences with upgradings made with diacetyl (butter-like), aldehydes, esters, sulfides, etc. We could taste these components and their contributions to the coffee, and the concentrations required for positive taste benefits. This was exciting applied science.
The green coffee bean buyers worked on an empirical tasting program tied to low priced canned coffees, and even then resented the intrusion of scientific method as applied by chemists, engineers and food technologists.
Lingle, Ted, SCAA Coffee Cupper’s Handbook & Basics of Cupping Coffee 1990
Elkin, M., SCAA Cupping 100, Houston, Texas, 1994
Sivetz, M., AVI Coffee Technology & Coffee , Origin & Use, 1979
Sivetz, M., Coffee Quality, 1995
Food Technology, V26 No. 5 p70-77, Acidity & Coffee Flavor, 1972
SIVETZ CHECK LIST ON COFFEE BEAN PREPARATIONS FOR TASTE EVALUATIONS
LEARNING TO TASTE
One of the greatest apprehensions a person has, when considering entering the coffee business, is the anticipated training and education required for tasting different origins and different defects in coffees.
Fortunately, most people have the natural facilities for smelling and tasting, and it is simply orientation and experience that are required.
Most coffee "cuppers" and buyers have learned their skills under the tutelage of a senior person in a large coffee company.
Knowledge of tasting terminology makes it possible to effectively communicate with exporters, brokers, peers, and customers. COFFEE TASTING has a language all its own. It is not very difficult, but it encompasses a breadth and depth of experience that cannot be learned overnight.
Without a grasp of this language and education, one can become a victim of the green coffee bean seller or broker, because it is difficult to convey the short comings of the offering. Learning the trade accepted taste terminology also helps one communicate more effectively with employees.
It is important to taste beverages on the same turn table with an expert in order to have the opportunity to discuss the source and cause of tastes identified. There are tastes, for example, like bitter which taste acid to some, and one must be aware of such genuine taste impressions.
Another obstacle to learning coffee tastes is the secrecy that many coffee buyers hold on this subject, since it constitutes their livelihood. They do not want to create competitors for their job, nor do they want to share the details of their taste decisions. The buyer may be buying marginal quality green coffee beans and is not willing to share this information or to discuss his taste impressions on decisions to buy.
When you hear of taste tests with coffee carried out by lay or general public, you can be sure that you are asking a tongue uneducated group for opinions. The results are usually strange, if not erroneous. The tasters cannot communicate properly .and the scope of their knowledge is small.
You will find casual terminology in flyers published by sellers of roast coffee to the Gourmet Trade. For example, the following terms have been taken from 25 word descriptions in the Superior Dowe Egbert flyer; and they are not meaningful or used in professional green coffee buying & tasting:
These words are usually created by advertisers.
The Professional terminology following was taken from Coffee Technology 1979 Table 15.1:
It is important to note that persons who are trained in chemistry and have had the opportunity to smell unique chemical odors, have an advantage in identifying characteristic odors coming from coffee.
Gas chromatographic releases of individual chemical compounds and odors make it possible to speak of acet-aldehyde pungency, or acetic acid, di-acetyl (buttery), methyl mercaptan (potent), buty-ric acid, etc.
The usual coffee buyer does not know his chemistry, and hence does not appreciate these odor sensations.
INSPECT GREEN BEANS
When receiving a green coffee bean sample from a broker, it is necessary to visually inspect the spread of beans for color, color variation, bean size, bean shapes, and general uniformity. Smell the green beans to determine if there are any "off" odors, like mold, ferment, or foreign contaminants. Note the number and type of defects refer to the grading chart. If there are many defects, sort out the defects and weigh for wt% content. One may sort out all the black defects to see what effect this has on taste (often notable). Roast a 2 ounce (70 gram) sample. Note odors during roast and uniformity of color developed. If roast color is not uniform, the beans are not uniform. Note "popping" sounds while roasting as index of bean quality.
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