August 09, 2022


It’s quite a journey that coffee takes. Starting as a green seed in a red cherry on a bushy tree in the equatorial mountains, eventually becoming the intoxicating brown brew in your favorite mug. Since you asked, we’re going to pull back the curtain back a bit so you can learn how it happens.


Coffee is a seed. It is the seed of the fruit that grows on coffee trees. Coffee trees grow near the equatorial belt, and coffee is basically divided into two main categories – Arabica, and Robusta. Metropolis only works with Arabica coffee. In the Arabica category, there are tons of varieties with cool names like Bourbon, Catuai, Caturra, Typica,Geisha, Sidra, and Maragogipe, among many others.

Coffee is harvested at different times in different parts of the world but generally speaking (and with some exceptions) Central American and East African coffees are winter/spring harvest, South American coffees are late summer harvest, and Indonesian coffees are winter harvest.

Once harvested, the coffee is ‘processed’, meaning the seeds are removed from the fruit, then dried, milled, and sorted before export. In total, it will take a coffee between 2 and 4 months from ‘picking ’ to arrive at our dock.


The fruit of a coffee tree is called a ‘cherry’. Ripe coffee cherries are harvested (picked), in many cases, by hand. Pickers must be careful only to harvest those cherries that are truly at the peak of ripeness. Each cherry holds 2 seeds (except in rare circumstances). There are around 3000 seeds (beans) in a pound of coffee, so it takes 1500 hand selected coffee cherries to make a single pound of coffee!


The cherry has a skin on the outside. Inside the skin is a sticky, grape-like substance called pulp. Inside the pulp are two seeds (except in peaberries where there is only one). Removing the seed from the cherry is called processing, and processing takes three main forms – natural, pulp-natural, and washed. Each form lends itself to different cup profiles.

Natural Process

In ‘natural processing ’, the seeds are dried inside the cherry. The dessicated cherries are run through a mill to separate the seeds. Natural processing tends to produce coffees that are fruity with loads of body.

Pulp-Natural Process

In ‘pulp-natural’ processing, the cherry skin (but not the pulp) is removed from using a grinding disc, then the seeds in pulp are allowed to dry. Once dry, the seeds are run through a mill to remove the pulp and any skin or parchment. Pulp-natural processing tends to produce coffees that taste clean, layered and juicy.

Washed Coffee Process

In the ‘washed coffee process’ the skin and a majority of the pulp is removed from the seed using a

grinding disc, then the seeds soak in a water bath for 2-3 days. After washing, the coffee is dried, then the parchment and skin is removed in a dry mill. Washed processing tends to produce coffees that taste clean, acidic.


After processing and drying, coffee is sorted for any defect before packing in plastic lined burlap sacks, prior to export. This sorting is often done by hand!


As a roaster, we solicit samples from farms, then sample-roast the coffee in our lab in tiny batches (100 grams at a time) on a nifty Probat 2-barrel sample roaster. Once a coffee is sample roasted, we ‘cup’ (taste) it using the Q-Grader protocols, meaning we have an established system for tasting and scoring the beans. We’re super careful in tasting our samples because of two VIPs. 1) You. We have your tastes in mind. This is our chance to find just the right coffee for you. 2) The grower. As you’ve read, there is an incredible amount of work that went into the coffee before we get to sample the goods. To be sloppy would be disrespectful.


If we decide to buy a coffee, we’ll sign a contract for the amount that we need, then wait. It can take months for the coffee to arrive because beans are usually shipped in containers. Once the coffee arrives stateside, we pull a small sample and taste it again against the original sample to make sure that nothing has changed. If not, we give it the ol’ thumbs up and bring it into our roasterie and warehouse.


Like many other agricultural products, coffee futures are traded on the commodity market. Think ‘pork bellies’ or ‘frozen orange juice’ from Trading Places. The coffee price (C Price) largely influences the price per pound for most (not all) of the raw coffee bought and around the world.

The C Price refers to a certain grade or class of coffee. Commodity grade coffee. Typically lower in quality than specialty grade. Coffees that are higher in quality are priced higher using ‘differentials’. Specialty coffee, for example, is assigned a higher price point. Coffees lower in quality or defective are priced lower.

Coffees can also have a differential for non-quality reasons. For example, Certified Fair Trade and Organic coffee. Fair trade coffee, specifically, has a minimum price in addition to a fair trade premium.

Metropolis Coffee purchases only specialty grade coffee (scores at least 80/100). Moreover, we always purchase either fair trade coffee or other coffee purchased well over the fair trade minimum price. In fact, at the time of this writing, we are the largest roaster of fair trade coffee in the state of Illinois! We’re extremely proud of this fact.

A lot (if not most) coffee farmers live in poverty. Most factors affecting the price of coffee and the price of coffee production are well out of the control of the farmers. Futures markets, climate change, changes in global demand. As I write this, the price of fertilizer is way up because of the war in Ukraine.… It is important that roasters like Metropolis do whatever is necessary to pay fair prices and to do our part to make sure that coffee farmers are not exploited. This is a complicated issue and there are many ways we can go about working toward this form of systemic change.

Metropolis is also a large purchaser of Certified Organic Coffee. We are certified organic by the USDA and our facility and records are audited and inspected annually to maintain compliance and integrity. We pay fees to the certifiers and differentials to the producers for organic coffees.


Ok, we decided that we want to buy a coffee and we’ve brought it into our warehouse. Now what? Next step is that we develop our roasting recipe. Every coffee is a little different. Difference in density, moisture level, bean size, etc will affect how the coffee will get roasted. So, to get it right we’ll do several test roasts, cataloging all the important roast data as we go. We taste all those test roasts the next day in our tasting lab, then tweak from there. Finally, after much consternation, we arrive at our ‘the roasting curve’, which is a graph of heat over time.


We’ve bought the coffee. It’s sitting on a pallet rack. We’ve developed our recipe. It’s sitting in our vault (ok - bulletin board above the roasters’ desk). Now … now we wait for you to order. Seriously. We don’t roast your coffee in advance because we roast to order. Roasting to order ensures that the coffee will arrive perfectly fresh!

When you (finally) order, we do a happy dance, then get to work.

We have three roasting machines and four roasting humans. 

#1 is a 15-kilo capacity Probat UG-15 Roaster from 1933. 

#2 is a 45-kilo capacity Probat UG-45 Roaster from 1950

#3 is a 60-Kilo capacity G-60 Roaster from 2011.

  1. The first step is to weigh out the raw coffee, depending on the machine we plan to use for your order. If we only need a small amount, we’ll use roaster #1. 
  2. Once we weigh out the beans, we load them into a 450 degree roasting drum using a giant suction system. The drum spins slowly and large paddles inside the drum scoop and drop the coffee over and over again to make sure the beans roast evenly. Once loaded in the drum, the beans begin to absorb the heat from the drum. The roaster will add a lot of additional heat during this stage in the roast by firing the gas burners below the drum at close to full throttle. Going too slowly could make the beans taste flat or woody but caution! Going too quickly and we’ll scorch the bean.
  3. Minute 1-4. The beans transform from jade green to a pale yellow as they dry out.
  4. Minute 5-9. The bean color changes from yellow to light brown as the sugars begin to caramelize. Toward the end of this period, the roaster coffee will throttle down the heat, heading into the 8th minute. 
  5. Minute 9-10. This period is called ‘first crack’. At this point the coffee begins giving back some of the energy it has absorbed. It will expand rapidly and make an audible cracking sound. Like Rice Krispies, more or less. The smell at this point is unmistakable and intoxicating.
  6.  Minute 10-12+ This is the time between first crack and second crack. Depending on whether we’re looking for a light medium or dark roast, we’ll stop the roast suddenly by opening the drum door and dropping the beans into a metal tray called a ‘cooling tray’. 
  7. The cooling tray has a stirring arm and fan - a bit like stirring your soup and blowing on it. The point is to cool it to room temperature as quickly as possible.
  8. Once cooled, we run the beans through a machine called a ‘destoner’. This machine removes anything heavier than coffee from the coffee. Like rocks or nails from origin. Your coffee grinder thanks us for this step!
  9. The last step before bagging is a QC measure. We are sure, at this point, that we followed our roasting curve, but we take a measurement of dark roast coffee level using a ‘laser color analyzer’ to make absolutely sure that we nailed it. Gotta be consistent!


The right way to roast is to pay attention to all the variables that affect the coffee - variables like the size of the roast, the age of the bean, moisture levels, ambient heat in the room, etc, and even with all of that going on, produce a consistent product, batch after batch. It’s a little like landing an airplane with variable weather - no matter what that plan has to get down safely and in the right spot. A lot of people are depending on us to get it right. Even so, we try to keep it like. We have tons of quirky art and tchotchkes around the roasting area. We crank fun music. We joke and grab beers after work. It’s actually pretty chill. Camaraderie comes first.

If you’re ready to try a freshly roasted coffee from our crew of roasters, don’t forget to take our Coffee Quiz. We’ll help you pick a winner. Or, try our Roasters’ Choice Collection.

Cheers! Skal! Sante! Salud! Kampai! Happy Brewing!