Sample Roasting with the Stronghold S7 Pro – A Reflection by Ian Fretheim

Posted on April 12th, 2017


In November of 2015, I made a trip to South Korea to visit a roaster manufacturer called Stronghold Technology. The four-drum sample roasters that we had been using were in need of an upgrade: Digital probing had verified significant variability between the barrels, and Cafe Imports was expanding its operations such that our remote offices were also in need of calibrated sample roasting. While my colleague in the sensory analysis department, Megan Person, had become an expert on our drum sample roaster, increases in sample volume at our HQ and the lighter staffing that we were using in the offices abroad both demanded that we adapt.

At that time, Stronghold was relatively new. Information about the company was difficult to find, and long-term reviews were nonexistent, but there were two things I knew: Stronghold built an automatic roaster with a batch size small enough for samples. Their original roaster, the S7, had a 850-gram capacity. I became interested in the S7 in part because Stronghold claimed that it could roast, save and replicate profiles with as little as 150 grams of coffee. That sounded a heck of a lot like an answer to my sample roasting situation. The larger batch size would also come in handy for cupping events, while the automation would allow salespeople to roast their own samples rather than relying on Megan and I.

I decided to make the trip and check them out for myself. The potential upside was so great that if the trip turned out to be a dud it would still have been justified.

I spent two days roasting on the S7 in Stronghold’s office. I didn’t produce exactly the roasts that I was looking for. My investigations into the S7’s capabilities were too broad–can it do this, can it do that, what if I change this parameter, etc. I needed to feel good about the roaster’s potential, and see as much of the S7’s range of application as I could. Perfecting roasts was a task for a later date. Based on the range of roasts that I was able to accomplish, and seeing the S7’s ability to replicate those roasts, I came home confident that I had found our machine.

Now it’s 17 months later, and we’ve been using the S7 almost exclusively for our sample roasting for about a year. The ease of use, the quality and consistency of roast, the scalability and the ability to build and share profiles between roasters–all these things have made the S7 a truly remarkable tool for our sensory program.

It has been an absolute pleasure working with Stronghold, and I look forward to many more years of it. They’re going to be at SCA Expo, and I strongly encourage you to check out their booth–and the version of the S7 that they’ll be releasing for sale here in the U.S.A. That’s right. The S7 that I’ve been raving about is no more…

Stronghold is moving forward with a second-generation roaster called the S7 Pro. We’ve just received ours, and I can say that everything has been improved-even things we didn’t know needed improving. From the user interface to the probing, from the PID controller to profile replication, even with practical things like chaff collection and clean out, I was gobsmacked unboxing and firing up the new machines. The only thing the S7 Pros don’t do is make breakfast, which I’ve heard may be part of the first software update…

–Ian Fretheim

Café Imports Director of Sensory Analysis

Stronghold has also released a video testimonial with Ian commenting on his experience working with the S7. You can watch that at this link:


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