Learn to Refurbish Your Own Mahlkönig K30 Grinder with Coffee Tech Central’s Dirty K30 Class

After unearthing a treasure trove of used Mahlkönig K30 espresso grinders, coffee tech wizard Jon Ferguson is sharing the love.


Photos courtesy of Coffee Tech Central; feature photo: Jon Ferguson and Tamara Vigil at work on some of the K30s set to be refurbished

When a major drive-through coffee chain in Lincoln, Neb., decided to ditch their traditional espresso machines and go super-automatic, Jon Ferguson of Coffee Tech Central saw a great opportunity. He took it upon himself to adopt the dozens of Mahlkönig K30 espresso grinders that would have otherwise gone in the trash and give them new life. After refurbishing and selling quite a few himself, Jon had a cool idea: Why not invite people to his lab and teach them how to refurbish the grinders themselves?

And with that thought, the Dirty K30 Class of 2022 was born. Coffee professionals and enthusiasts everywhere are invited to join the class on October 1, where they will learn from Jon and his team of tech experts how to dissemble, repair, and strengthen their new grinders.

“The grinders [I received] ranged from poor to excellent condition,” Jon says. “Over the past year, I’ve refurbished more than 40 of the Mahlkönig K30 Step, Vario, and Air models, and I’ve learned a great deal about the grinders. With the [few models I have left], I wanted to share with others the opportunity to learn how to refurbish and calibrate espresso grinders and understand as much as possible how they operate through a hands-on, guided experience.” 

Jon Ferguson works on a Mahlkönig K30.
Longtime coffee professional Jon Ferguson, who owns Coffee Tech Central in Lincoln, Neb., will host a class called the Dirty K30 in which students can refurbish one of the many Mahlkönig K30 espresso grinders he recently acquired to gain knowledge and take home a fully operational grinder.

Jon ran a small trial version of the class in January of this year in which students gained important skills and knowledge about their grinders. In the course of the day, participants learned how to completely take apart and reassemble their grinders and gained confidence on how to maintain and replace burrs. Grinder maker Baratza has held similar classes teaching users how to repair their machines.

Jon shares that this class isn’t limited to café baristas or shop owners: Anyone looking to buy an espresso grinder for their café or home is welcome to participate. The class will be a full day (approximately 8 hours long), and students will get to take home their newly refurbished grinders after class. There are also several spots available for those who don’t wish to purchase a grinder but would like hands-on experience learning how to refurbish one. In addition, students will receive extra training on espresso and calibration.

Students at a table with disassembled grinder parts.
Jon did a test run of the Dirty K30 class in January, and students loved learning more about how to care for their espresso grinders.

“I hope that everyone (who partakes in this class) will get the confidence to operate and care for their espresso grinder in a manner that will help ensure a longer life and less service calls,” Jon states. “For example, replacing K30 burrs will be much easier and better installed after the amount of hands-on experience students will receive in this class.” 

A sample of parts removed from a Mahlkönig K30 grinder.
Which part goes where? This pile of Mahlkönig K30 grinder parts might look daunting to you now, but after taking the Dirty 30 class at Coffee Tech Central, you’ll know every detail about them!

Jon will be hosting The Dirty K30 classes while inventory lasts. The first class is scheduled for October 1, but you can keep an eye out for scheduled classes here or email coffeetechcentral@gmail.com to sign up directly.


Based in Los Angeles, Emily Joy Meneses (she/her) is a writer and musician passionate about culture and collective care. You can regularly find her at Echo Park Lake, drinking a cortado and journaling about astrology, art, Animal Crossing, and her dreams. Explore her poetry, short stories, and soundscapes on her website.

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