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Brewing has been a major part of humanity since the dawn of time. Archaeological evidence suggests that humans discovered and leveraged the magic of fermentation as far back as 12,000 years ago in Mesopotamia. By 4000BC, beer was a part of daily life through Mesopotamia and Egypt with the knowledge and techniques growing and passing through the Greek Empire, Roman Empire, into ancient Germanic culture, Asia, and Africa. Vikings brewed, Explorers brewed, and generation over generation, the techniques and understanding of brewing and fermentation have expanded, and continue to expand even today. (Ref: The Complete Idiot's Guide to Beer Tasting, Rita Kohn, Alpha Books).
Fast forwarding to today, an explosion of the "Craft Brewing" movement around the world has brought back an interest in production of beer at a smaller scale with a focus on quality, unique flavour, and the utmost care and attention to much more select and unique brews. For those that choose to study the craft of brewing, there is a wealth of information and technology that wasn't available to our ancestors - specific knowledge of yeast cultures and microbiology, grains, enzymatic processes, fermentation, bitterness, carbonation, and many other variables.
For the home brewer, having this knowledge and being able to take advantage of it can sometimes be two different things. Brew days are a flurry of activity, and typically require concurrent management of a number of different systems and processes. Precise temperatures, volumes, timing, and workflows contribute to excellent beer. However, being able to repeat them on subsequent batches is equally important, as you can easily lose "the magic" of a beer in a subsequent brew if you don't follow exactly the same process. While this is impossible to achieve 100% of the time, any tools and techniques that help to maximize accuracy and repeatability are highly valued.
This is where BrewCentral comes in!
BrewCentral was designed to be the ultimate add-on to a typical all-grain home brewing rig. We were specifically concerned with creating a toolset for:
- Managing Temperature - The multiple phases of a brew have specific temperature targets. To complicate matters, you are frequently pouring hot water into room temperature grain and brewing vessels while trying to hit specific temps. Great brewers have complex calculations and knowledge of their equipment, but even the best can't be as accurate as a computer.
- Managing Volume - In general, you are trying to hit specific volumes for your grain mashing and lautering processes. This is where the science of repeatability comes into play. BrewCentral leverages flow-meters and a real-time integrator to calculate volumes accurate to a few percent, making concentrations and transfer times very repeatable.
- Managing Flow Rates - During the Lautering phase of the brew, careful management of outflow of beer wort into your kettle, while managing an inflow of fresh water to rinse the grain results in both a high efficiency extraction of carbohydrates from your grain, but also enhances repeatability of your recipes.
- Managing Time - With many of these activities occurring concurrently on a brew day, sometimes you just need a good ole' fashioned timer to remind you when you're supposed to move to the next step, add hops, or finish your boil!
The next two diagrams should give you some context to what goes on during a typical brew cycle. Although it seems straight forward enough on paper, be assured that there are a lot of moving parts when you undertake this in the physical world. Missing your temperatures, or not having enough hot water to hit the exact volume you wanted are usually not fatal to a brew, but they reduce accuracy and repeatability significantly.
The Mash Cycle is key to extracting the right carbohydrates and nutrients from the grain. Getting temperature and volume correct is key to extracting the ingredients you want, but also key to avoiding unwanted compounds and enzymatic reactions that add unwanted off-flavors in your beer.
After mashing for an hour or so, Lautering is the process of extracting the wort from the mash. Ideally, you'd like to leave behind any husks, loose grains and other debris, extracting only pure clean beer wort for the remaining steps in the brewing process.
Lautering involves a unique process called "Sparging" which is basically rinsing the grain with fresh water to extract the last of the carbohydrates and other desired nutrients. Although different methods for Sparging exist, we favour fly-sparging which involves matching the outflow of beer wort to the boiling kettle with the inflow of exact-temperature, heated water to the top of the grain bed in order to create a rinsing action.
Once your lautering cycle is complete, you typically have a kettle full of nice fresh wort that is ready to be boiled! That's where BrewCentral taps out, as the boil is a fairly analog and simple process.
BrewCentral leverages 5 key building blocks to achieve brewing automation:
- Android Things Controller - Our main system controller uses the TechNexion PICO-PI-IMX7 Android Things Starter Kit to control the system state along with implementing the entire workflow. The brewer is prompted to make the appropriate state changes along the way, and can monitor temperature, volume, and flow inside the system in real time as the brew advances.
- Servo Controlled Valves - We designed and 3D-printed mechanical components to mount servos to simple analog ball valves normally found in a home brewing rig. These valves are PID-controlled to provide the specific flow and temperature required by our recipes.
- Flow Meters - We leveraged GEMS FT-330 turbine flow meters to measure flow coming out of ourmixer into the grain mash, and out of the grain mash into our kettle. The FT-330 is a food-safe flow meter good up to 80C
- Temperature Sensors - We leveraged a couple different types of sensors. First, a one-wire protocol, Waterproof DS18B20 Digital temperature sensor is used in our mixer pack where hot and cold water are combine. Second, we leveraged an industrial K-type Thermocouple with a long stainless steel probe for our grain mash temp.
- Arduino Real Time Controller - A real-time Arduino Due micro controller drives our various sensors, combining all of the flow, temperature, and valve pack control into a coherent package. PIDs are used throughout the system to managecontrol of valves and temperature set points. UART is used to communicate between the Android Things control unit, and the real-time system.
Our hardware architecture is pictured below. At a high level, it is a typical "gravity-fed" home brewing rig that has been augmented with digital valve control and flow and temperature measurement at the strategic points. Our overall goal was to make a system that could be used to augment a typical home-brewing rig that someone might already use in their garage or backyard.
We'll be the first to admit that it's harder than we thought to combine and control so many real-world variables in a single system. Managing flow rates and volumes in tandem with temperature, all in real-time in a relatively dynamic environment was not trivial, and we learned a lot about the hardware, and software implications of trying to control these scenarios.
The Temperature Mixer Module
We're very proud of our temperature mixer module. It is definitely the workhorse of the system.
- Precise Temperature Control - The two servos + integrated temp sensor are capable of real-time adjustment to temperatures across a wide range. A PID controller analyzes temperature output, making dynamic adjustments to hot/cold inflow.
- Precise Flow Control - The integrated flow meter is accurate from about 0.5L/min up to full flow. A second PID modulates flow in, while an interrupt-driven tick counter reads the ticks from the flow meter, allowing us to integrate for total dispensed volume.
The combination of flow control from our Temperature Mixer, and volume measurement by our mash-outflow allows our Lautering Controller to automatically match the flow rate of incoming sparge water to outflow into the boil kettle. This used to be a manual effort on the part of the brewer, but is now automatic.
- Automated Match of Outflow/Inflow Volume - Once the system begins dispensing sparge water, the flow rate out of the mash is measured and used to automatically modulate the inflow coming from the mixer. This results in exact maintenance of volume and headspace above the grain during the lauter.
- Stuck Sparge Detection - Sometimes, the flow rate will slow, or even block temporarily. The system detects this in real time and opens and closes the valve going out to the kettle in order to try clear any obstruction or restriction. If it cannot be cleared, inflow will automatically halt allowing the brewer to correct.
- Configurable Endpoint - The system allows the user to configure the endpoint of the sparge as a % of total volume. This allows for maximum efficiency, as ideally the wort should drain completely from the mash into the boil kettle without any wort left in the mash at the end of cycle.
Cloud Support and Recipe Database
Although we would have loved to get there, we have not yet implemented support for Google Cloud. Our long term vision is to create a database of recipes that can be used with the system, and allow a way for others to author and share their own recipes.
Currently, the recipe is completely data-defined, but just not dynamic. We hope to get there soon. Stay tuned!
Dynamic Adjustments and Recording
Currently, BrewCentral allows the brewer to do some real-time adjustment to their recipe in order to compensate for temperature, flow, or volume discrepancies. Our long term goal is to actually record these adjustments so that they can be incorporated into future brews.
The idea would be that if, say, the brewer adjusts a volume at 21 minutes into a lauter, or brings the mash temp up a degree or two, we would record this and then replay it automatically on subsequent repeat brews of the recipe in order to ensure the ultimate repeatability of your recipes.
Expanded Workflow Process
While the core technology and workflow of the BrewCentral is complete, automated blockage detection, ability to create custom workflows, and testing over a wide range of home brew rigs is still required. We learned a lot of during our full grain test runs that still need to be implemented into the workflow to ensure consistent results over a variety of equipment.