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Since 2012, coffee has been a large hobby of mine. I began with a low cost espresso machine and moved into freshly grinding coffee. From there, I began trying different kinds of coffee beans at different roasts. This further moved into examining new ingredients in an attempt to create chocolate mixes for mochas. In the spring of 2016, I began roasting my own coffee beans and also developed an automated system for doing so.

 

Espresso Creations

An excel spreadsheet was created in order to log and track various data on coffee drinks -both alcoholic and non-alcoholic. It includes bean origins, roasting times, and various amounts ingredients that were tested and incorporated into the beverages.

Coffee Log – Last Updated: 10/21/2016 

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Automated Roasting System

Conventional home coffee roasters can easily cost over $100 and generally consist of a heating element, some form of actuation, and a timing system. Upon exploring the world of coffee roasting, it was found that popcorn poppers can achieve the correct temperature that is needed to roast coffee and cost a fraction of the price of a coffee roaster.

It was my goal to create a coffee roasting system that was cheaper than the conventional ones but still offered actuation and improved capabilities that would be desired by coffee roasters. The overall objectives were the following:

  1. Minimize Price- Purchase as few materials as possible and use parts that were already owned with preference over buying new ones.
  2. Actuate Coffee- Add a servo system on to a popcorn popper in order to avoid any required manual agitation of coffee beans.
  3. Automatic Startup and Stopping- Create a system that can easily start and stop and allows for variable time settings.
  4. Self-Contained System- Create a system that only requires a simple “wall plug-in” and doesn’t require an external computer to run.
  5. Expandable- Create a system that can be eventually expanded to allow for PID control of the roasting system and espresso machine. Also include the ability to expand the full system to grinder for automated weight-based coffee dispensing.
  6. Gather Data- Log temperature data over time and actuation data. Export this to an SD card that can be inserted into a computer in order to provided data analysis.

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Currently the system is used regularly for roasting coffee beans. FDA approved high temperature adhesive is used in the area where the beans would touch the friction bearing. A power button turns it on and the temperature/roasting time is displayed on a LCD screen. An Arduino Mega controls the system with a relay turning the roaster on and off, a servo actuating the coffee, and a type K thermocouple providing temperature data.

Known Issues:

  1. LCD Screen will begin to display miscellaneous characters after a certain amount of time. Diagnosis/Planned Fix: I initially though that this was due to a lack of power but now believe that this screen may just be broken.

Planned Upgrades:

  1. Attach an SD card reader for data logging.
  2. Attach buttons to allow roast time selection without the need to use a computer for reprogramming.

Coffee Agitation Program – Last Updated:  11/7/2016 

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Espresso Machine

In the winter of 2016, this Gaggia Classic espresso machine was purchased as a used product. It was a widely recommended machine for home baristas who did not want to spend close to $600+ for a decent espresso machine. While this machine performed well in almost all areas, it lacked in the quality of its frother.

In order to make a latte with a good texture (and also make great latte art) , one must be able to create a good microfoam in the milk that he/she is heating. The Gaggia did not have a frother that was able to effectively do this.

After looking online, it appeared that many had upgraded their frothers by using the frother from a Rancilio Silvia V1 machine. The only problem with this was that these frothers were outdated and notorious for breaking.

It was claimed that in order to attach the newer version of a Silvia frother, one would need to buy a full valve assembly ($70 for the valve assembly vs. $30 for the frother alone) and then further modify that.

I was able to make the correct adjustments and find the correct fittings that allowed me to attach this new frother with less hassle.

 

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