The Story of Our Storied Coffee Roaster
In coffee, as in life, change is the only constant. From the beginning of Kaldi’s Coffee, we’ve seen specialty coffee explode in popularity and diversity. New and innovative processing methods have come into vogue, and there are more consumer choices than ever—from origin to roast to flavor profiles to brewers—being presented and explored.
What hasn’t changed recently, however, is the machine that roasts your coffee. There has been one stalwart present through much of this new millennium — a reliable, trusty, cast iron thing-of-beauty laboring behind the scenes and roasting the best coffee we’ve tasted, day in and day out.
This blog is our ode to our vintage Probat drum roaster, Roxie. Here, we dive into what we think makes it so special and why we choose it to roast the bulk of our coffee. We also interview some of the people that lovingly rebuilt it and have been roasting on it every day for the past decade.
FIRST, WHAT IS COFFEE ROASTING?
Before we get started, let’s cover the basics. Coffee roasting is simple on the surface — make green beans brown — but getting the most out of a coffee is an art and a science.
Coffee is usually roasted between 300 and 450 degrees Fahrenheit for a variable period of time. The exact time and rate at which it reaches its final temperature, and the controlled fluctuations of airflow through the roaster, are what determine the unique “roast profile” of the coffee roast.
As an example, consider the widest gap of our coffee blends, Breakfast and Cafe Malta. Breakfast maintains many of the natural acids (i.e. fruitiness, complexity) of the green coffee due to less time and sometimes less temperature in the roaster. Cafe Malta, on the other hand, has a roast profile of deep chocolatey sweetness that comes from longer, slower roasting.
Our coffee roasting is still a very hands on process — these decisions about time and rate are executed manually by our coffee roasting team. We’ve covered what’s happening inside the beans as they roast, but the main idea is that we’re caramelizing natural sugars found within green coffee to get your coffee tasting just right. Routine quality control is conducted to make sure each coffee is tasting to spec. This ensures your favorite blend tastes the same whether it’s January or June.
In the end, it all comes down to the individual and the machine that's doing the work.
The trier from our Probat Coffee Roaster
WHY WE CHOSE A PROBAT COFFEE ROASTER
There are dozens of manufacturers of coffee roasters all over the world. In fact, many of these manufacturers are newer companies that have formed in just the last 30 years or so. There is one name in particular, however, that has stood the test of time: Probat. In existence and producing coffee roasters since the late 1800's, Probat is the oldest continually operating coffee roaster manufacturer in the world.
A lot of work goes into sourcing our specialty coffee and Probat machines harbor the right balance of controls and qualities to help us get the most out of each bean.
Per Tyler Zimmer, green buyer, Q-grader, and experienced roaster: “Every coffee we buy, from the densest Ethiopian coffees from Yirgacheffe, to the delicate coffees from Central and South America, have unique properties. Our Probat Roasters give us excellent control—from airflow, to gas fire controls, to the consistent heat of the cast iron —the tools we need to develop and coax the best flavors in each coffee.”
...But not just any Probat
The roasters we use are refurbished, classic cast iron machines built before the 1950’s that have been retooled with modern roasting amenities. Before the 1950’s, Probats were manufactured almost entirely out of cast iron, something that is not true of many modern machines for cost and manufacturing reasons.
Our coffee roaster has been fitted with modern sensors, but is still manually operated and consisting of original parts.
We prefer these cast iron roasters because they are energy efficient, retain their heat well, and spread heat evenly. This leads to fewer defects in the roast and gives us the consistency and predictability that we need when roasting, especially when going from roast to roast. This, as you can imagine, is a core need for us to ensure your cup of 700 always tastes the same. Our Probat roasters are also natural gas fired (meaning a flame heats the coffee roaster), and the heat from the flame, the heat from the cast iron, and the control of airflow gives us many tools to develop the best flavors in each coffee.
For these reasons, we sourced and lovingly restored our 75 kilo Probat, originally made in 1937, in the early 2000s. It has gone through a few upgrades and changes through the years, but this piece by piece restoration was a testament to the quality, potential, and timelessness of a Probat cast iron drum roaster.
Checking out the Probat before bringing it to our St. Louis Roastery
BUD, OUR LEAD ROASTER, ON OUR PROBAT
Bud, who originally started over 15 years ago in our Kirkwood cafe, has done countless roasts on our Probat. We asked him to provide some of his own experiences and background:
“I have actually never roasted on any other production roaster other than a Probat. I personally prefer it over other roasters that I have seen in operation, learned about, or tested because of its cast iron build and just its overall quality.
As a little bit of trivia, we actually lovingly call our 75 kilo Probat “Roxie”. The original restoration process of Roxie took several days and nights. On one of the final nights, after we did some “seasoning” of the roaster (taking some coffees REALLY dark), the song “Roxeanne” came on the radio. Our roaster is red - “put on the red light” - and someone threw it out there and the name just kind of stuck!
If you come to the warehouse, you may notice how old our roasters are. These pieces of machinery are testaments to the way machines were made in the past. I haven’t met a coffee professional who has come to the Roastery and not said “wow, that’s a beautiful machine”. We take it for granted because we see it everyday, but I like to remind people of how special it is.
I actually met one of the heirs of Probat, who actually runs their company museum, many years ago and I showed her a picture of the machine. She was in awe because she didn’t know there was a 75 kilo up, running, and looking so good. I’d like more people to appreciate Roxie as kind of a living historical monument.
Old, but still operating like new.”
MAN, MACHINE, AND YOUR MORNING CUP
We’ve talked many times about the coffee quality chain from farm to cup. Direct relationships with producers, careful picking and processing, extensive cupping sessions, best brewing practices, and world-class barista training all ensure that when you’re served a cup of our coffee, it’s the best that it can be. Our Probat coffee roaster has been a part of all of those stories for years, and the people and passion behind it are a core part of our identity.
The next time you sip on your cup of Cafe Kaldi or 700, know that a story is unfolding before you stretching back centuries - from the discovery of coffee, to the forming and molding of cast iron plates, to the training of a passionate coffee roaster ready to take the controls and roast you the best coffee in the world.
And before we go...
Roxie is not the only Probat coffee roaster in our warehouse. We actually roast on two vintage Probats — one for smaller roasts, one for larger — and proudly display an ultra-rare, nearly one of a kind 5kg Perfekt Probat coffee roaster in our cupping room. It is a piece of history, and while getting it operational is a major future goal, we're proud to give it a home.
MUCH MORE THAN A BLEND: CAFE KALDI
- Much More Than a Blend: 700 | Kaldi's Coffee Blog
- Why Fresh Roasted Coffee Matters | Kaldi's Coffee Blog
- Est. 1994: DeMun's Origin Story | Kaldi's Coffee Blog
- Roasting | Kaldi's Coffee Education Page
Coffee Processing and Your Cup | Kaldi's Coffee Blog