US 5,375,508 · Granted 1994-12-27

The Patent That Made Coffee Makers Actually Smart

Bunn figured out how to let coffee machines think for themselves. Instead of just heating water and hoping for the best, their system uses a separate control box that learns the perfect timing, temperature, and water flow—and lets you tweak everything with buttons instead of guessing.

Curated and verified by the IsItPatented Editorial team

The plain-English version

What it protects

The claim covers a programmable control system for coffee brewers that includes a detachable input device for adjusting brewing parameters. What's protected here is the specific architecture: a main control module that stores and manages function limits (like water temperature, flow rate, and dispensing cycles), paired with a separate handheld input device that lets users select which function to adjust and increment or decrement its limits. The system's water valve control—which periodically dispenses water to prevent overflow—is a key protected feature.

Why it matters

Commercial coffee brewers needed smarter controls to compete with each other, and this patent gave Bunn a way to lock down the idea of separating the brewer's brain from the user interface. By making the control module programmable and the input device removable, Bunn created flexibility that competitors couldn't easily copy without infringing. For high-volume operations like restaurants and offices, the ability to fine-tune brewing cycles without replacing the whole machine was genuinely valuable.

Real-world use

Every time a barista at a cafe presses buttons on a separate control panel to adjust brew strength or water temperature on their Bunn machine, they're using the exact system this patent describes.

Original USPTO abstract

A control system for a beverage brewing apparatus which includes a programmable control module and a separate input device. The control system is used with a beverage brewing apparatus of the type having an infusion assembly for retaining and filtering a brewing substance, a heated water source and a water distribution system for transporting water from the heated water source to the infusion assembly. The programmable control module controls numerous adjustable functions associated with the brewer and stores at least one function limit for each of the functions which it controls. The separate input device is selectively attachable to the control module for manipulating the function limits of the programmable function retained and controlled by the control module. Function controls are associated with the input device for selecting a function to manipulate and for incrementing and decrementing the limit or limits of the selected function. The control module and input device allow selection of control limits which affect a valve for controlling water flow from the heated water source to the infusion assembly. These control limits establish a dispensing cycle which periodically dispenses water from the heated water source through the water distribution system to the infusion assembly to prevent overflowing the infusion assembly.

Patent details

Publication number: US 5,375,508
Filing date: 1993-12-29
Grant date: 1994-12-27
Assignee: Bunn-O-Matic Corporation
Inventor(s): KNEPLER; JOHN T., GEOCKNER; VICTOR D.
CPC class: G05B19/108

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