Part 2: The Coffee Cherry: From Fruit to Bean – But What Is It, Really?

Introduction

Welcome to part 2 of our series "The Complete Coffee Guide: From Bean to Brew"! In the previous article, we looked at the coffee tree itself – how it grows from a tiny sprout to a plant full of beautiful flowers and eventually berries. Now we're going to dive deeper and take a closer look at the cherry on top, the fruit: the coffee cherry.

You may have heard of coffee beans, but what exactly is a coffee cherry? And what is hidden inside this small, often red, wonder? Understanding the structure of the coffee cherry not only gives us fascinating insight into the world of coffee but also helps us understand why coffee can taste so incredibly different. Join us on a journey into the anatomy of the coffee cherry!

The Coffee Cherry – More than just a bean, actually a seed.

On the coffee tree, fruit grows that resembles cherries, which is why they are often called "coffee cherries" in English. Botanically, the coffee cherry is actually a drupe, just like plums, peaches, and – yes, cherries. This means that the fruit has a soft outer layer (pulp) around a hard "stone". But in the case of the coffee cherry, the "stone" is what we are all after: the coffee bean itself (which is actually a seed!).

Let's dissect: The layers of the coffee cherry

To truly understand what happens on the journey from cherry to bean, we need to look at the different layers a coffee cherry consists of, from outermost to innermost. The illustration was made by our roast master Trude:

1: Exocarp: This is the outermost layer, the "skin" of the cherry. It starts green and changes color as it ripens – usually to red, but sometimes yellow or orange, depending on the coffee plant variety. The skin is thin but protects the contents.
2: Pulp/Mesocarp: Right under the skin, we find the pulp. This layer is rich in sugars and pectin. The amount of sugar here is very important for certain processing methods (such as natural and honey processes), where the sweetness from the pulp is absorbed into the bean during drying. This layer is often simply called "pulp".
3: Mucilage/Parenchyma: Within the pulp lies a sticky, slimy layer that is also rich in sugar and pectin. This layer adheres tightly to the next layer, the parchment. The sugar here is important for the fermentation process in washed coffee. More on that in the articles about processing methods.
4: Parchment/Endocarp: Now we're getting close! This is a harder, papery layer that encloses the actual coffee bean(s). It feels a bit like parchment paper, hence the name. The parchment protects the bean during drying and storage before export. Coffee sold with this layer intact is often called "parchment coffee".
5: Silver Skin/Epidermis/Testa: The very last, thin layer that clings directly to the coffee bean. It is a thin membrane that protects the seed itself (the bean). Much of the silver skin falls off during roasting, but you can often see remnants of it in the small crease in the middle of a roasted coffee bean.
6: Endosperm: Finally! Deep in the core, we find what we call the coffee bean – usually two pieces lying flat against each other. This is the actual seed of the coffee plant. It is this part that we roast, grind, and brew to make the fantastic drink we love. It is also the origin of the world's worst coffee joke: The taste is like the coffee bean – divided in two. The bean consists of plant fiber (cellulose), oils (lipids), sugars, organic acids (such as chlorogenic acid), proteins, minerals, and, of course, caffeine. The composition of these substances gives each coffee its unique flavor potential. This is what we refine during the roasting process. Perhaps we will delve deeper into the chemistry of the coffee bean in a future blog post.

Fun Fact: Peaberry

Sometimes, only one bean develops inside the coffee cherry instead of two. This single bean then often becomes rounder in shape because it didn't have another bean to lie flat against. These are called "peaberries". They are sometimes sorted out as separate lots. Some believe they have a more concentrated flavor, but that's a matter of taste!
At Kaffa, we have several times bought lots of peaberries, but exclusively because of their quality. There is no evidence that peaberries in themselves are better or worse than regular twin beans.
And yes, there are also cherries with three seeds, but this is of little importance for coffee production.

Why is anatomy important?

Knowledge of the coffee cherry's layers is not just for dedicated enthusiasts. It helps us understand:
Processing methods: How the layers are removed (skin, pulp, mucilage) dramatically affects the flavor. We will explore this much more in the next articles! 
Quality: The parchment protects the bean from moisture and damage before roasting.
Roasting: The remaining silver skin can affect the roasting process and flavor if there is too much of it.
Flavor potential: The bean's chemical composition itself (influenced by species, soil, climate, etc.) lays the foundation for all the flavors and aromas that develop during roasting.

Summary

The coffee cherry is therefore a fascinating little package full of surprises! A drupe where the "stone" itself is the seed we know as the coffee bean. Each layer – from the outer skin to the sugar-rich pulp, the protective parchment, and the thin silver skin – plays a role on the way to the finished cup of coffee.
Now that we know what's inside a coffee cherry, we're ready to look at what happens after the cherries are harvested. In the next part of the series, we will explore the first major processing method: the dry method, also known as natural processed.

Navigation in the series:

Part 1: About the Coffee Tree, from Planting to Harvesting
You are here: Part 2: The Coffee Cherry: From Fruit to Bean – What's Inside?
Part 3: Coffee Tree Species and Varieties

Curious about how the different layers affect the taste? Explore our selection of coffees processed in different ways to taste the difference!