On an overcast afternoon in April, I found myself handing off a strange piece of equipment to be trucked to Las Vegas. It came into my possession in a bankruptcy that still shocks people. And it was the cornerstone of a contraption that won the Murder Hobos a spot on the podium of DEF CON's most unpredictable hardware event, the Beer* Chilling Contraption Contest.
In its 21st year, Beer Chilling has a long history as a sideshow and contest at DEF CON in Las Vegas. Others have recounted the full history better than I can. The rules are simple: Cool a beverage from some high temperature to some lower temperature. Measure how long it takes to do that. Don't mess up the beer. Get a score, iterate, and improve. The quirkiness and creativity keeps me coming back as a spectator and contestant. It doesn't hurt that they bring more and better components every year where people can build and compete entirely with on-site materials with the help of incredible volunteers. But the kookiest ideas are reserved for the Unlimited segment where people bring their contraptions from miles around to compete. tinribs and melody-rs, parent-child team members of the Murder Hobos have stuck their toe in the water with Hacked devices at previous years. This year, they had an eye on a design, and I helped acquire some key components. This serendipitous acquisition would allow the three of us to make a proper run at Unlimited, the no holds barred part of the competition.
In November 2025, news broke that Rogue Ales was bankrupt. A fixture of PNW craft brewing would be broken up and auctioned off out of their brewery/warehouse on the harbor. While browsing the auction site, tinribs lit upon the lab's dusty PolyScience circulating chiller which retails for over $5000 brand new. It works by running a compressor for cooling in tandem with a heater for precise temperature control via sensors with a tolerance of .01C! One could place an object within the body to chill it, or you could pipe the chiller liquid out of the chiller for cooling outside the unit. $250 YOLO bid and a week of nail-biting later, it was his. The only problem was it was in Newport, Oregon, 1000 miles away from home. I jetted down from Portland metro the next weekend and picked it up, and he made his way to me in April 2026 for the exchange by car. Before they left home, I tested it and found that, barring a slow leak, it still worked just fine. Whew. With a device whose pedigree could not be denied, the chiller was going to be the cornerstone of our Beer Chilling Contraption for 2026.
The hard part would be turning serendipity into success. We couldn't just show up with a commercial chiller. It needed to be part of a larger contraption. tinribs got to work. He had acquired two big dispenser plates from soda vending machines. And a 3D printer board could be a control head. But the chiller allowed the entire contraption to be fully regenerative: only electricity, not ice, dry ice, liquid nitrogen, or any other substance would be needed to restart the cooling process and make another run. The design eventually morphed into the following stack of components:
- Control Head:
- 3D Printed Peristaltic Pump
- 3D Printer Board running Marlin
- Stepper Motor
- Raspberry Pi
- Thermistors
- Thermal Battery:
- Cooler
- Soda Machine Dispenser Cooling Plates
- Phase Change Material coolant packs
- Regenerative Loop:
- PolyScience Circulating Chiller
Behold! The Machine!
The cycle design looked something like this:- The chiller cools the battery to a certain low temperature.
- The control head pumps the beverage into the battery.
- The battery cools the liquid (without freezing it!)
- And the chiller restores the battery to equilibrium for the next run.
A host of tweaks followed. In testing, the deep freeze -20C PCM packs had to be swapped out for less-aggressive -8C versions. An alcohol rinse was added to ensure all water was purged after a run. The final settings were dialed in with a control page that not only accepted settings values but also displayed sensor history. We calibrated the machine the day before with 5% alcohol solutions carbonated with a Sodastream and microwaved to 100F/38C. All of tinribs and melody-rs' hard work and testing was about to pay off.
On the day of, we hit the contest floor and felt the energy. The booth was crowded and covered in buckets of water and ice, dry ice fog, and discarded beverage containers from runs past. Fire marshal violations were posted proudly on the most dangerous-looking devices (while making it clear all violations had been remediated). Eager contest goers were still experimenting as the clock ticked down. Each team got three runs, and everyone was using theirs to the fullest.
The contest runners greeted us with amazement. This was a contraption in the real sense of the word. We found electrical power and waited for the battery to come to temp: 2.5C. The 110F/43C car ride 45 minutes from home had done its worst, and our late arrival compounded the time pressure. After 45 minutes, we were coming down to the wire.
While we waited, I explained the machine to the curious (plenty of those at DEF CON) and tinribs set up the control head. I bought Bud Lightbeer's BCCC SAO. This is an official temperature keeping device for the contest, and it runs off an electronic badge! tinribs hit a snag with the awful DEF CON wifi. The open network is never reliable, but we thought it might afford us at least token access to a simple web server. Deauth packets were being more annoying than usual, and we couldn't maintain a connection for longer than 20 seconds. Panic! We broke out the backup screen and keyboard. Always bet on a hard line.
The run was over almost as soon as it began. A hot beer was pulled from a bucket being kept at 100F by a sous vide stick. There was some struggle to deliver a proper beer without so much foam to match our calibrated liquid volume, but we finally got 330g of Bud Light at 97F, the timer started, and the drink disappeared down the 3D printed receptacle as the pump whirred to life. The Hacked bracket hosted an impressive 920W run from a can shaken in an ice bath. Q, a research chemist, looked on as we made our attempt. 1'06" later, we measured a cool 34.7F. We came in second overall and sat atop the Unlimited bracket with over 850W of power sucked out of the drink in that time. Because of our battery regen time, we could not attempt a second run, but we were not complaining.
The BCCC might not look like something that would thrive at DEF CON. Chemistry, specific heat, phase changes, tubing, and liquid sensors aren't standard features of many computer conventions. But observing the people that are drawn here makes it click: A team of kids was chilling soda with their parents by pouring from bucket to bucket. The all-women team Eutectic Point flew their ice-bath heat exchanger from across the country to compete. And we all shared a love of creating something that we could explain and improve.
I was not a primary designer or tester on the contraption this year, and I appreciate being able to ride along with tinribs and melody-rs and take to the contest stage in victory once more. Many thanks to them, the other contestants, Rogue Ales for allowing us to salvage something from their demise, and the wonderful contest volunteers, especially the few veterans returning for the first time in a long time. Next year, the BCCC promises us more: ice, dry ice, and equipment to try. And we promise to bring it with a pit crew's practice, and maybe a few more tricks up our sleeves to drop our time and raise our wattage.
* Note: The BCCC is now 21, and it can drink. It was known by Beverage Chilling Contraption Contest in the past!