When it Comes to Bottling Your Beer, the Right Caps Help You Seal the Deal

Not all bottle caps are made the same, and the difference in quality could mean a spoiled run of beer that was otherwise destined for greatness.

John Holl Jun 25, 2019 - 5 min read

When it Comes to Bottling Your Beer, the Right Caps Help You Seal the Deal Primary Image

Andrew Holzhauer was stocking bottles of a beer 4 years in the making into the taproom cooler at Funk Factory Geuzeria (Madison, Wisconsin) a few months ago when he and a colleague decided to open and split a bottle.

The beer, The Last Four Winters in Wisconsin, is a blend of 1-, 2-, and 3-year lambic-style ale that had bottle conditioned for 15 months before its release. The release was actually in two stages. The first happened in December 2018 during a formal celebration where customers left with cage-and-cork-topped 750ml bottles. Then, a smaller run was put into 375ml bottles, capped, and sold in the tasting room. Over the course of a few months, the cooler supply was replenished with the stock from the storeroom.

The small bottle that Holzhauer, the head of operations at the brewery, opened showed signs of acetaldehyde, “a touch of Windex, not super acidic but not something that was present in the beer to begin with. And this surprised me because the beer was still fully carbonated, but there must have been some kind of oxygen ingress.”

The plot thickened, briefly, when the pair opened a second bottle that had been in the cooler and found it to be in perfect shape. They weren’t content with calling the first-off bottle an anomaly, and a closer examination revealed a difference in caps.


We have inventor William Painter to thank for the bottle cap. The Baltimore resident filed a number of patent applications, starting in November 1889, for a device that he called the “crown cork,” which was essentially a metal disc that could be crimped around a bottle to be sealed. It was a revolution on a number of levels. An actual cork was no longer needed to seal a bottle; this device was cheap, easy to make, and reliably held in liquid. He received the patent in 1892. Since then it has appeared—mostly true to its original plan, although with upgrades to materials and other small improvements that have helped to keep beer fresh—on countless bottles around the globe.

During the bottling run at Funk Factory Geuzeria, the brewery had temporarily run out of their usual caps made by Pelliconi, an Italian bottle-cap manufacturer, and used a bag of 100 caps that they had from a local homebrew-supply shop. “The Pelliconi caps have this really nice interior seal where it meets the lip of the bottle and curves with it,” Holzhauer says. “The homebrew caps were just totally flat on the underside of the cap and just had a smaller point of contact with each bottle.”

One hundred caps is a relatively small run, and looking at the stock of Four Winters, Holzhauer was able to see the line of where the good caps ended and the bad ones started.

But there was a wrinkle.

According to his brewery logs, twenty-six of the caps were affixed to bottles of another beer: Cervino Gewurztraminer. The brewery opened a few bottles of it with the bad cap and noticed similar off-flavors to those in Four Winters. A few of the bad-capped bottles made it out to the public via the tasting room.

Rather than hide the news, the brewery took to social media—not only their own pages but also online forums—to share what they had found, alert any affected customers, and, in a way, alert the larger brewing world to the importance of good caps.

The response, he says, has all been positive, with people appreciating the transparency and launching into theories on caps, aging beer, and more. Holzhauer, who worked in software before beer, says that he took an analytical approach to the problem at first, not assuming that it was just a one-time problem. “It’s good to be pessimistic about the scope of an issue because you get ready for what could be a larger problem.” From there, once the issue was identified, he was able to add a personal touch to the message and admission, which he believes is the best course of action.

Funk Factory offered a refund or a replacement bottle (of a different beer: Cervino Riesling) for anyone with a bad-cap release and learned a good, and not too costly lesson, on the importance of the right equipment mattering each and every time.

John Holl is the author of Drink Beer, Think Beer: Getting to the Bottom of Every Pint, and has worked for both Craft Beer & Brewing Magazine® and All About Beer Magazine.