August 22, 2018

A Home Roaster’s Guide to Buying The Right Green Coffee


You’ve got your roaster. You’ve read all about how to roast. And you can’t wait to get started. But what’s missing?

The coffee.

As a home roaster, you have the thrilling ability to select which green beans you roast and accentuate their best characteristics, all ready for you to make your very own brew (or give the beans to a lucky friend).

But the world of green bean purchasing can seem overwhelming at first. How can you find the right coffee for you? Fortunately, there are some simple ways to understand the differences between green beans and find (at least) one lot that will suit your tastes.

Lee este artículo en español Guía Para Tostar En Casa: Comprar El Café Verde Adecuado

Using a Hottop roaster for sample roasting. Credit: Roast Rebels

Not All Green Coffee Is The Same

A Colombia or an Ethiopian? A washed or a honey? A Bourbon or a Typica-Caturra blend? There are so many types of green beans and the differences between them affect both how the coffee tastes and how you should roast it.

Here are some of the most important points to consider:

1. Origin: The conditions in which a coffee is grown, including the climate, humidity, and soil, have an effect on its aroma and flavour. Go from big to small – taste coffee from different countries, then try different regions, before comparing the differences between farms and lots from one area.

Find out more in our One-Stop Guide to Terroir & Why It Matters!

2. Varieties: The coffee species and variety (which is the genetic category below species) have a remarkable impact on the brewed coffee. Drinking a yellow Bourbon, an SL-28, or a Gesha are completely different experiences.

Learn more! Read A Crash Course in Coffee Varieties

Sorting through freshly picked coffee cherries on a Honduran coffee farm. 

3. Altitude: In general, the higher the elevation, the lower the temperatures. This can cause green coffee to grow more slowly and allow the sugars to develop more. The result? Brews with more complex taste profiles, sweetness, and often more acidity than those grown at warmer temperatures.

When considering altitude, though, don’t forget that different regions have different temperatures. For example, it’s too cold to grow coffee higher than around 600 m.a.s.l. in Hawaii, yet Kona coffee is well-regarded. On the Galápagos Islands, specialty coffee can grow at around just 200 m.a.s.l. Keep this in mind when comparing coffees, especially if they’re from different countries or even continents.

Discover how to roast high-altitude coffees in Roaster Basics: How to Roast Hard & Soft Beans

4. Processing: This is how the coffee beans – or, to be more accurate, seeds – are removed from the fruit.

In natural/dry processing, the entire cherry is dried before the outer fruit is removed, giving it a sweeter and fruitier flavour. Wet/washed coffees have been removed from the fruit before drying, and so they tend to be less sweet but much more clean. In turn, this allows the acidity to shine. Honey processing removes the skin but leaves some of the mucilage, or flesh, around the beans during drying. This creates a sweet and full-bodied flavour, compared to washed coffees.

You may also encounter other processing types: monsooned, wet hulled, experimental… These are often specific to one farm or region. For example, monsooned beans have been stored in warehouses in the humid Indian monsoon season.

Check out How to Roast Honey & Natural Coffee

Washed and natural processed lots dry side-by-side in Honduras.

How to Find The Right Green Coffee For You

Knowing which coffee you like starts with tasting. A lot of tasting, in fact.

Try a range of different coffees and take notes on each one. Rate every cup on a scale from one to ten. Then add notes on the acidity, sweetness, body/mouthfeel, and aftertaste. You could also comment on the flavours and aromas in the cup (both those you liked and those you didn’t). Where possible, write down the origin, variety, elevation, and processing method.

Do you see any patterns? You’ll soon develop an idea about which coffees you like and which you don’t.

If you’re brewing coffee that someone else has roasted, inspect the beans and take notes about the roast degree. Are they oily? Chocolate-coloured or more like cinnamon?

Roast level affects the flavours and aromas of a coffee. Generally, the lighter the roast, the easier it is to taste the beans’ unique profile, including any fruitiness and acidity. This is because the roasting process introduces more toasty notes, which can easily overwhelm the delicate natural flavours of the bean. A darker roast will usually have greater body, less acidity, and an oilier surface.

You might also like Everything You Need for a Home Roaster Starter Kit

Where possible, drink at specialty coffee shops and opt for single origin coffees rather than blends. This will allow you to both ask baristas questions about the coffees and clearly taste the differences in the origins.

Different coffees being cupped at Roast Rebels. Credit: Roast Rebels

Practical Points to Keep in Mind

There are a number of online suppliers who can ship worldwide. But before you commit to an order, consider the cost, availability, and other practical points.

Some green beans may be harder to find during certain seasons. Coffee is an agricultural product, which means it has a harvest season. Different countries, however, have different harvests. And just like with bread or fruit, freshness affects quality. You don’t want to be buying coffee that’s a year old or more.

Other coffees may be unrealistically expensive for your daily drink. And some suppliers only sell large quantities. Are you really going to roast and consume all those beans? And even if you would, do you have enough room to store them?

Sample roasting coffee. Credit: Roast Rebels

Once You’ve Bought Your Beans

Now you know a bit about green coffee beans, you’ve sampled several, and you’ve taken notes. That means you’re ready to purchase some and begin roasting.

Start with experimentation: take one lot and roast it with three to five different profiles. Then, take a few lots and roast them all with exactly the same profile. Take notes on the results of both these tests to help you understand the impact of roast profiles on different beans. Then, do all this again with different beans and profiles until you craft your perfect coffee.

A cupping is also a great way to learn a lot in a short time. These events allow you to try a bunch of coffees in one session and take notes on what you taste. Oh, and learning how to cup will help you evaluate your own coffee’s quality.

How do you find out about cupping events? Watch out for coffee festivals, follow local specialty coffee shops and schools on social media, and keep an eye on your country’s Specialty Coffee Association (SCA) website.

The SCA also offers courses on coffee sensory skills and roasting. These can be valuable tools for home roasters. And, of course, you can find a lot of information on typical profiles online and in books.

Want even more tips? Read Learn How to Roast Coffee With These Resources

Before and after: the green and roasted coffee beans. Credit: Roast Rebels

There’s nothing quite like roasting your own coffee. It dramatically expands the range of green coffee you get to choose from and allows you to find – and craft! – the perfect brew for you.

And remember, research is useful but the best way to learn is by experimenting. The more you taste and compare, the easier it will be for you to find your favourite bean. What are you waiting for?

You might also like Everything You Need for a Home Roaster Starter Kit

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