With so many amazing options on the market for home coffee roasting, how do you find the best green coffee beans?
The selection process can be tricky, because the criteria for selecting green coffee beans for home roasting are completely different than those of selecting roasted beans, because with home roasting there are three new variables introduced:
- Bean Quality / Grade
- Bean Size and Consistency
- Bean Traceability
The Problem with Buying Roasted Coffee
One of the biggest benefits of roasting your own coffee is that you get to see the beans before they are roasted. Roasted coffee bean labels almost never provide any detail on the grade of beans that were used in the roasting process, and because the roasting process conceals almost all bean defects from the consumer it is nearly impossible to visually gauge the quality of roasted beans.
Pro Tip: A single bean defect can destroy the flavor of an entire pot of coffee
Quality green coffee, however, usually does provide detail on the grade, and our goal with this guide is to help you learn how to find the good and avoid the rest.
Understanding the Coffee Bean Grading Process
Unfortunately, there is no worldwide standard for grading beans, but the most commonly used and accepted is the SCAA Standard, developed by the Specialty Coffee Association of America.
Key Point: Green coffee beans are graded based on the percentage beans that show "defects", not on the flavor of the "good" beans
When green coffee is graded, the primary measurement is the number of defects per 350 grams (the typical quantity in a standard size bag of roasted beans sold in stores). The highest coffee bean grade is classified "Grade 1: Specialty Grade", but even with Specialty Grade up to 5 full defects are allowed, so always be sure to inspect your beans.
Because defects are generally obvious on green beans, to save money some home roasters choose to buy a Grade 2 (Premium Grade) and remove the bad beans on their own. While this plan is plausible, the cost difference between the two grades is relatively small (and in our opinion) not worth the risk of missing a few defects and having one affect your brew.
The Importance of Bean Size when Home Roasting
Everyone knows small potatoes bake more quickly than large potatoes, and the same holds true with roasting coffee beans. For home roasting this is critically important for three reasons:
- Roast Consistency: If the beans are not the same size, they will not roast at the same speed. Inconsistent bean sizes produce a mix of overroasted, properly roasted, and under-roasted beans in every batch.
- Roast Speed: Because smaller beans roast more quickly, they also change from perfectly roasted to over-roasted more quickly, thereby requiring more precision during roasting
- Roasting Motion: Large, flat beans can be more difficult to roast evenly than smaller beans, particularly when using a less commercial method of roasting (such as an oven or skillet).
Purchasing Specialty or Premium Grade beans will ensure your beans are of a highly consistent size, but individual determinations must be made for bean size based on your personal roasting method and experience level.
Using Traceability to Evaluate Flavor Potential
The most important detail provided on the labels of good green coffee beans is the information tracing the beans to their point of origin. Quality beans will also often feature not only the country or origin, but also the specific area (or even better, the specific farm and/or cooperative -- including the name of the farm manager). Quality beans will also provide you with detail on the processing method(s) were used to prepare the beans.
Purchasing Specialty Grade beans will help ensure you consistently produce a well-roasted, flavorful cup of coffee. When selecting the specific type of beans you will use, ensure sufficient traceability information is provided and always choose beans in a size category that matches your personal roasting process.
If you have any additional questions, please let us know using our Contact page. We are always happy to help fellow home-roasting enthusiasts!