Gearhead: Running A Warm Bottling Line

There are some breweries, especially those specializing in secondary fermentation, that are taking steps to warm the beer before it goes into the package. As they will tell you, it makes a big difference

John Holl Aug 12, 2019 - 9 min read

Gearhead: Running A Warm Bottling Line Primary Image

Photo by Jamie Bogner

For those breweries that package, an automated bottling (or canning) line is obviously a necessary piece of equipment. And it is actually mesmerizing to watch as bottles (or cans) are fed into the machine, lined up, rinsed, filled, topped, sprayed, and sent off to be packaged with others.

You’ve probably noticed when you’ve been on brewery tours that the employees manning the line wear gloves. This is in part for safety reasons, but it’s also because it’s cold. Standard filling lines run the beer right from the bright beer tanks and into the bottles or cans, and when the beer comes out of the bright tank, it’s anywhere from just above freezing to the 40s Fahrenheit.

That makes sense for the majority of beers—especially for lagers, which thrive under colder temperatures, and even for most ales when it comes to serving temperatures. But for the breweries that practice bottle- or can-conditioning, where yeast is added to a bottle or can to ferment the residual sugars in the beer and thus create a more layered and effervescent beer-drinking experience, cold filling has it disadvantages. Typically, the ale yeasts these brewers use need warmer temperatures to get down to doing their job. So if yeast is added to a package with cold beer, it needs to wait until the beer warms to begin the important fermentation work.

We all know that there’s a lot of passion behind beer, but breweries are also businesses, and the sooner that beer is ready for distribution and consumption, the sooner breweries get paid and can make more beer, and the happier we consumers are. So, any advantage—as long as it doesn’t impact the flavor, quality, or integrity of the product—is a good one.


A few years back, Phil Leinhart, the brewmaster of Brewery Ommegang (Cooperstown, New York) was visiting colleagues at Duvel in Belgium. The two breweries make similar beers, but the European counterpart has a bit more history than the American craft brewer, and with that history come some tried-and-true techniques that have helped the brewery succeed.

As they were watching the bottling line run, Leinhart noticed that hooked up to the bright tank were two heat exchangers that were warming the beer from the cold-conditioning temperature into a more manageable one that would allow the secondary fermentation to begin almost immediately.

“From a timing standpoint, it just makes sense,” Leinhart says. “Bottling the beer cold out of the bright tanks at 32°F (0°C) and then transferring it to our warm room, it just takes a while for the beer to come to temperature so the yeast can get to work.”

So Brewery Ommegang installed two heat exchangers in its packaging line. The first uses steam to heat water. It’s set to about 77°F (25°C). Then the second one uses the warm water to warm the beer before it’s packaged. The temperature of the beer that goes into the bottle is about 64°F (18°C).


It’s an automated system, and both heat exchangers are on a closed loop because if a system should fail or get stuck, Leinhart notes that they wouldn’t want “the beer to start cooking in the lines.”

The other key piece of equipment for this kind of filling is the actual filler. “You can’t just use the one that comes off the rack,” Leinhart says. Bottling warm means higher volumes of CO2, so you need a higher-pressure filler to keep the gas in solution.

In addition to faster delivery time, there’s been one other benefit for Ommegang: consumer packaging. Leinhart notes that before warm bottling, the cold beer was packaged into cardboard holders or cases. As the cold beer was brought up to temperature in the warm room (usually held at about 70–75°F/21–24°C), condensation would form out the outside of the bottles, potentially weakening the commercial packaging.

Craft beer is still a collaborative industry, and brewers are, more often than not, willing to share what they’ve learned. The adage of a rising tide lifts all boats applies here. So, when Jason Perkins, the brewmaster of Allagash Brewing Company (Portland, Maine) heard what Leinhert was doing, he asked to stop by and take a look. “We bottle-condition/can-condition everything,” says Perkins. “No matter what beer we’re making, we bring it up to warm-room temperature. Bottling at about 45–50°F (7–10°C) just takes more time to get the beer warmed.”


Previously, as other brewers still do, bottles were transferred from the line and into plastic crates with openings along the side to allow for air flow and then moved to the warm room. Still, it was a slow process because the bottles on the interior of the crate were insulated by the other bottles, taking longer to warm up and allow the yeast to work. After seeing the Ommegang setup, Allagash installed one of its own.

“There’s a slight difference in layout,” Perkins says, “but we basically copied what they did.”

The results have been noticeable.

“We did some studies internally. Under the cold-filling method, the outside bottles warmed up in a day or less. The bottles inside might take 4 to 5 days,” Perkins says. “So the beer needed more time in the warm room, and we all know that keeping beer warm for long periods isn’t necessarily a good thing.”


Since Allagash switched to warm filling, the time in the warm room has decreased.

Allagash White, for example needed 8 to 10 days before and can now be released within 5 days. Bigger beers such as their Tripel used to take 3 to 4 weeks; now its time in the warm room has been lowered to 2 to 3 weeks. It has also eliminated the extra time needed to move the beer from the plastic crates into final packaging when the beer is ready.

“It’s been great for us,” Perkins says, “but now we have several hundred plastic crates that we don’t need to use anymore. So if anyone is interested in buying them, call me.” There are other methods to warm up a beer before bottling. Several years ago, Tomme Arthur, the brewmaster of The Lost Abbey (San Marcos, California) started thinking about warming up his bright tank before beer went into the bottle.

The brewery fashioned a system by hooking up a hot water heater to its glycol system to circulate the liquid around the tank, continually running through those lines “rather than going back to the roof” where it would cool back down.

Running the glycol at about 85°F (29°C) around the 200bbl tank (although the beers usually range from 50 to 100 barrels), it takes about a day to get the beer from 34°F (1°C) to about 55°F (13°C). Using a carbonation stone, the beer is then dosed with lager yeast and packaged.

“It’s a very sanitary process,” says Arthur.

As more breweries experiment with intentional refermentation and look to get beer to the market a little faster, a few steps at the packaging phase might be a boon. “I think it’s really beneficial,” says Leinhart. “For our refermented beer, I’d never go back to the other way.”

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.