The San Franciscan Roaster Company (Coffee PER Inc.)

History

The company comes from a repairer's trade, not from a design office. Sherman Dodd left school at sixteen for the oil fields. A coffee agent then hired him to install industrial roasting machines, and Probat recruited him right after. From this stint with others came Coffee PER, a company that began by installing and refurbishing before building its own machines. The trade press dates the company to 1992. The workshop ended up settling in Nevada. It was still in Fallon at the end of 2013, and it is in Carson City by August 2015 at the latest. In 2008, Bill Kennedy bought Coffee PER Inc. from Dodd. Kennedy was not a mechanic by training: he had been a teacher and then a middle school principal for about twenty years, after studying industrial management. He widened the range beyond the SF-1 and SF-6, and made a name as a trainer for small roasters. His death was announced on December 11, 2025. The company changed hands in June 2026. Dave Marson, founder of Nature's Bakery then of Marson Foods, is the owner, and Matthew Sewell, engineer at the workshop since at least 2015, is the general manager. Eight people work there.

What it makes

A single type of machine: the horizontal-drum roaster, heated with natural gas or propane. The drum is single-wall, in mild steel rolled in the United States, of a grade the company calls schedule 40. Schedule 40 designates a standardized series of steel tube thicknesses, that of common industrial piping, and not a particular alloy. No cast parts. The choice of the single wall is embraced and argued: a second sheet would screen the bean from the flame, and is of interest only if the metal conducts poorly. Heating is from below, with brass burners mounted on a manifold. The orifices are drilled with a number 60 bit for natural gas and a number 69 for propane, smaller because propane carries more energy by volume. The bean therefore receives heat from the wall by conduction. Added to this is a convective share, which the operator doses with the draft lever. On the large models, a variable-speed turbine also gets involved. The faceplates are a quarter inch, or 6.4 mm, on the small machines, and five eighths of an inch, or 15.9 mm, on the SF-10 and SF-25. All the machines roast and cool at the same time. Measurement relies on two resistance probes, bean and ambient, a Watlow EZ Zone display and an isolated USB converter, readable by Artisan or Cropster. The integrated afterburners of the SF-25 and SF-75 are Weishaupt WG30 and WG40 burners, modulating and low-NOx, made in Germany. Assembly is done by hand in Carson City.

The models

Six models in the catalog. The SF-1 roasts 200 to 450 g per batch, three to four times an hour, or 1.4 kg in the hour. The manufacturer itself presents it as a sample and profiling roaster, not as a production tool. The SF-6 roasts 3 kg, minimum 1 kg, in ten to fifteen minutes, for 8.2 kg in the hour. The SF-Super 6 takes the same 3 kg batch, but climbs to four or five passes. It thus puts out 10.9 kg of green coffee in the hour, under 30,000 BTU per hour, on 120 V and 6 A. The SF-10 roasts 5 kg and puts out 22 kg in the hour; it was presented at the SCA show in Seattle in May 2018, announced then at a little under 30,000 dollars and delivered in 90 to 100 days. The SF-25 roasts 2.7 to 12 kg per batch, in eight to fifteen minutes. It requires 100,000 BTU per hour, plus 250,000 for its afterburner, on 220 V and 30 A. The SF-75 roasts 34 kg in thirteen to fifteen minutes, under 300,000 BTU per hour, plus one million BTU per hour of afterburner; it weighs 839 kg and fits in 60 inches by 96.

What you gain

The SF-75 weighs 839 kg for 34 kg of coffee, or 24 kg of metal per roasted kilo. This inertia holds the charge temperature from one batch to the next. It makes the announced four to five passes per hour credible. Power follows the law of surfaces: 10,000 BTU per hour per kilo on the Super 6, 8,300 on the SF-25, 8,800 on the SF-75. A large machine therefore demands less per kilo than a small one. The single wall removes a screen between the flame and the bean. The gas gesture therefore shows up faster on the probe.

What you lose

These 24 kg of metal per kilo store heat as much as they stabilize it: a drop in gas takes a while to show. The single wall, for its part, loses its heat faster between batches, and the manufacturer admits it. A morning with an irregular rhythm therefore costs gas. The measurement chain is read-only. Artisan and Cropster record the profile, they do not replay it, unless the automation option is fitted. On the SF-1, SF-6 and Super 6, the only live levers remain gas and draft. Finally, the SF-25's afterburner consumes 250,000 BTU per hour, or two and a half times the roaster it cleans.