Nostrovia Brewing develops automated keg-cleaning kart

Figure 1: The keg-cleaning cart is a compact and sanitary way to connect all sizes of kegs to the pump, valves and cleaning solution system. Source: Nostrovia Brewing

Champagne taste, beer budget

Nostrovia is a small, craft, brewpub featuring 16 taps supplied from a walk-in storage cooler containing a combination of eight 200-gallon serving tanks (for large batches) and numerous kegs (for small batches). Nostrovia typically brews seven barrels at a time for a total annual production of 200 barrels. A barrel is 31 gallons, but beer is generally stored and transported in a variety of smaller and more easily managed containers. A half-barrel, commonly known as a standard keg, a quarter-barrel is often referred to as a pony keg or slim, and a sixth-barrel is known as a “sixtel.” All these containers, which we’ll refer to as kegs in this article, are stainless-steel vessels with industry-specific fittings. Some kegs are leased and managed by other companies, but at Nostrovia, we chose to procure and manage our own fleet of kegs.

Keg cleaning requires connecting a keg coupler to the keg, so high-pressure hot water can be blasted in to dissolve solids. Some of these are organic in nature, but there are also mineral deposits or other precipitants—known collectively as “beer stone”—which build up on the vessel walls, over time creating places for microorganisms to take root and ultimately negatively impact the final product. Various detergents, acid blends, water and sanitizer agents may be used at the proper time, and all must be rinsed out. Compressed air is used in certain steps, and pressurized carbon dioxide is applied at the end to purge out oxygen, which is detrimental to beer quality.

The process can be performed manually, but it obviously requires a lot of hands-on attention, and there are multiple opportunities for inconsistency. Indeed, for the first years, our business cleaned kegs manually out of necessity. Some basic, keg-cleaning systems are commercially available in the $4,000 price range, but they're effectively not much better than manually cleaning because users must turn all the valves manually. Fancier systems with some semi-automatic operation and even advanced human-machine interfaces (HMIs) are available for much more money, and range up to $20,000 in some cases. I knew I could do better.

Figure 2: The control panel components were all obtained online from AutomationDirect, and the CLICK PLC provided an easy-to-program platform, with all the required I/O. Source: Nostrovia Brewing

The bottom of the barrel

The basics of keg cleaning are pretty straightforward. Hot water, chemicals, compressed air and carbon dioxide are needed, along with pipes, valves and a pump to move these process media and control their flows. A keg contains a spear which allow gas to enter near the coupler neck and fluid to exit through the tube that extends down. When cleaning, the keg is mounted upsidedown after a coupler is installed, which allows fluid to be blasted through the tube, cascade down the keg wall, and drain through the carbon dioxide port (Figure 1). A typical sequence might have several time-based steps such as:

• Dump residual,
• Hot water rinse,
• Caustic or acid detergent wash,
• Hot water rinse,
• Sanitize
• Compressed air after most steps to facilitate draining, and
• Pressurize with carbon dioxide as the final step.

I pretty much knew what was needed from a mechanical and plumbing perspective, and I was familiar with the use of automatic valves and instrumentation. It was straightforward to design a stainless-steel cart to house all these components, and the solenoid valves needed to actuate the process valves. The key was finding a complete portfolio of programmable logic controllers (PLCs), HMIs and wiring products that would make it easy to integrate everything with automatic control.

After some initial research, it was clear that the AutomationDirect Click PLC would fit the bill. So, in addition to the mechanical aspects, I designed an electrical panel to house the PLC and I/O modules with other associated buttons, circuit breakers, power supplies and wiring components—all sourced from AutomationDirect. The resulting control panel is compact yet serviceable, and it's configured to resist the effects of water (Figure 2).

Although I had no formal programming training, the Click PLC proved easy to learn and the programming software was free. AutomationDirect offers significant online training materials, along with responsive web and phone support. I was able to quickly self-teach myself to do the necessary programming, and I determined that a drum sequencer was the ideal way to control numerous devices through sequential steps. Programming and startup were accomplished within days, providing complete flexibility to modify the sequences and timing as needed. 

Right now, a standard sequence is used. In rare cases where a timing adjustment or other improvement is needed, it's easy to use a laptop to make any necessary changes. The materials for this fully automatic system were less expensive than buying a commercially available manual system, but labor was required to fabricate and program it.

Let the good times roll

But once the keg cleaning system was placed into service, the savings began to accumulate. Each keg-cleaning cycle operates for a reliable duration, saving costly hot water and chemicals. Workers appreciate that they can start a cleaning sequence and come back a few minutes later knowing the job was completed, with the cart ready for another keg. Cleaning is more effective, which improves our product quality and extends the life of the keg.

I'm already thinking about future improvements, such as adding an HMI for more detailed control and monitoring options, temperature control, pressure transducers and other options. Basically, the PLC platform provides endless options for continuous improvement.

The ease with which I created this automated keg cleaning system has opened up new possibilities for our brewery. We will likely develop the skid further, and offer it as an economical and high-performance solution we can sell to other brewers. The excellent experience with this project is also leading us to look at what other aspects of our brewery we can automate, such as canning, to provide better beer for our patrons.

Behind the byline

Jeff Lukasik is the owner of Nostrovia Brewing Co. in Erie, Pa. Throughout college and many years as a mechanical engineer for a large industrial company, he has sampled beers worldwide and developed his own brewing skills. In 2019, Lukasik applied mechanical engineering skills obtained at the Rochester Institute of Technology to build and operate his own microbrewery.