Automation helps turn home brewer into brew house

Automation methods used in a distillery are adapted for use in the fermentation process at a brew house.
By Avi Aisenberg, South Florida Distillers March 28, 2017

Figure 1: These conical, jacketed, 30-barrel tanks are cooled during the fermentation process using three glycol-filled bands. Courtesy: South Florida DistillersSouth Florida Distillers is the oldest distillery in Fort Lauderdale, Fla. The company now is branching out into the design business by working with 26° Brewing to help it brew world-class craft beers.

Greg Lieberman is the founder and owner of 26° Brewing in Pompano Beach, Fla. He began as a home brewer making 10 gal/batch in various locations, such as his garage, kitchen, a sibling’s backyard, and in a barn. Lieberman’s home brewing career saw about 100 batches in 4 years, totaling around 1,000 gal of beer.

After he perfected his craft, and with the help of South Florida Distillers, he scaled up the 10-gal recipes and began producing his beers in a state-of-the-art 30-barrel brew house (see Figure 1). The building now houses a sports bar, meeting space, a retail area, and a fully functioning brew house. The brew house can produce 30 barrels/batch, with 31 gal/barrel for a total of 930 gal/batch, or 7,440 pints. 

Distillery gets the brew flowing

Before creating South Florida Distillers, I took over the family plastics recycling and manufacturing business, which has since been sold. We recycled co-mingled large bulk plastics into plastic shipping pallets, primarily for the cruise line industry, using a unique structural foam injection process. It used the recycled plastic and made an 18-pound plastic pallet every 2 minutes using a single-shot injection molding process.

The machines were from the 1970s and 1980s. Most were relay-controlled using a 25-foot-long control panel full of hard-wired relays. Rebuilding the hydraulics and controls on the recycling machines using programmable logic controllers (PLCs) was a great learning experience, and it made the equipment more productive and easier to support.

After selling the recycling business, I started South Florida Distillers, a craft rum distillery. I have designed and automated portions of the inhouse rum distillery using a wide variety of control hardware. Our company was selected as the designer and integrator of the system for the new craft brewery after we demonstrated a 250-gal distillery fermentation tank using a PLC and temperature controllers to the owner.

Of course, it helped that Lieberman, the owner of 26° Brewing, was a long-time family friend. When he decided to open the brewery, we discussed in great detail the functionality he wanted, but couldn’t find on the market. That was music to my ears, so I got started on the design.

South Florida Distillers designed and programmed a touchscreen fermentation temperature control system for the new brewery installation at 26° Brewing. The controller initially is responsible for precise temperature stabilization and control of seven tanks, and is expandable to 16 tanks. 

Crafty brewing steps

Figure 2: An AutomationDirect Do-more PLC controls the temperature and level of the brewery’s seven fermentation tanks, as well as the brite tank and cold liquor tanks downstream. The automation system consists almost entirely of AutomationDirect componenThere are many steps to brewing beer, and this is not a complete list of process steps. During the initial steps, the grains are placed in a tank of water and heated-similar to a pasteurization process-to extract the starch. The grains are then strained out and the liquid is boiled, which converts the starch to sugar and also removes some water, increasing the sugar content of the liquid. After boiling for a time, the liquid is quickly cooled by running it through a plate-type heat exchanger. This cooling process also provides the opportunity for heat recovery for reuse in upstream processes.

After the beer is cooled, the tank is drained and pumped to a fermentation tank. Typically, these fermentation tanks need to be cooled due to the heat produced by the metabolic process of converting sugar to alcohol. The fermentation part of the brewing process is where the beer spends most of its time. For example, Pilsner beers ferment in about four days, and Lager beers take about two weeks. Controlling temperature during this "cold side" fermentation process is critical to the quality of the finished product.

After fermentation, the beer is transferred to the brite tank where it goes through a final quick cool, and a racking process to remove the beer off the top of the yeast, which settles to the bottom of the brite tank. From there, secondary fermentation may occur, such as by adding fruit. When this is complete, the final product is transferred to the cold liquor tank.

Automation system details

The automation system is based on an AutomationDirect PLC (see Figure 2) and touchscreen human-machine interface (HMI). The system controls the fermentation process in five stainless steel, 30-barrel conical fermenting tanks adjacent to the brew house. These tanks are located in the rear of the facility, with a tap room in the front. The windows behind the bar allow visitors to see the five fermentation tanks, one stainless steel brite tank, and one stainless steel cold liquor tank in the back room.

As of now, the brewery automation system only controls the temperature of these seven glycol-jacketed tanks, but it could be expanded to include pump and motor controls, steam flow control, and much more in the way of automating processes that are currently done manually. The automation system also was built to accommodate the addition of fermenting tanks in the future with minimal hardware changes and a simple software update. 

Fermentation control, the cold side

The general purpose of the cold side automation system is process monitoring, process control, data acquisition, and data logging of the fermentation process. Much of the process upstream of fermentation is controlled manually.

Although individual proportional-integral-derivative (PID) temperature controllers could be used at each of the seven tanks, the single controller was a better solution and less expensive. The added value from the PLC comes from the remote viewing and control of the process, and the ease of training new users. The design also required less work on behalf of the electrician, and will be less expensive when it comes time to expand the brewing process.

The PLC includes two multipoint ac output modules to control the 19 solenoid-actuated water valves. Seven resistance thermal detector (RTD) sensors are connected to PLC input modules to measure tank temperatures using clean-in-place RTD probes. Each of the five fermentation tanks has three cooling zones, with cooling solution flow controlled by one valve per zone, for a total of three valves per fermentation tank. The brite and cold liquor tanks each have two cooling zones and valves.

The temperature of each fermentation tank is controlled by a PID control algorithm running in the PLC. For each tank, a PID loop uses the tank RTD sensor as the process variable input, and controls three ball valves via the PID controller output. These valves control the flow of a glycol/water solution at each tank jacket. A ramp/soak pattern can be programmed to last for days or weeks based on the beer being fermented. Temperature control for the brite and cold liquor tanks is similar, except there are only two cooling zones and valves per tank.

HMI and remote access

Figure 3: This AutomationDirect C-more HMI simplifies recipe setup, and enables remote monitoring and control functions via mobile devices. Courtesy: South Florida DistillersThe HMI has a custom-designed user interface that mimics the flow of product through the brewery (see Figure 3). The controller and HMI are networked through an Ethernet switch as is a wireless access point, which provides network connections for both local and remote access to the touchscreen via iPad, iPhone, and Android apps running on smartphone or tablet mobile devices.

This system adds tremendous functionality and makes interaction with the automation system more user-friendly and easier to set up than with multiple temperature controllers. The automation system provides data logging locally at the PLC, and remotely through the Ethernet switch.

A free app allows mobile devices to remotely access the HMI. When remote access is enabled at the HMI and the app is installed on the mobile device, duplicate screens from the HMI can be viewed and controlled remotely from the mobile device.

All the process data is emailed to a selected group of users at periodic intervals or upon an alarm condition. Email addresses and recipients can be added or deleted at the HMI. High and low temperature alarms, deviation alarms, and other conditions can trigger an email. Text messages also can be sent to smartphones with the HMI. 

Installation and results

All wiring to and from the electrical cabinet including power wires, RTD temperature sensors, and cooling valve control wires were installed by a licensed electrician. The system startup was executed by Lieberman and me. The initial startup involved training the PID algorithms for the three different size fermentation tanks.

Each fermentation tank has three valves controlling the flow of glycol to the cooling bands. Training the PID loop for each tank required opening and closing the valves to see how quickly the temperature of the water in the tank changed.

Beer took a bit of retraining due to the exothermic reaction of fermentation, which is of course not present with water. Overall, it took six to 12 hours per tank to train the PID cooling loop, mainly because 1,000 gal of beer are slow to heat or cool.

The system performs as expected and Lieberman was able to sleep better knowing that each batch of beer has a watchdog to notify him and other operations personnel of any mishaps. There is always room for additional automation throughout the brewery. There are additional designs for motor controllers and valve routing systems ready to be built, but just waiting for the right time.

Avi Aisenberg is CEO and proprietor at South Florida Distillers, Fort Lauderdale, Fla. He has a degree in electrical and computer engineering from Cornell University.

This article appears in the Applied Automation supplement for Control Engineering 
and Plant Engineering

– See other articles from the supplement below.

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