Four of the Best Ways to Deaerate Your Brewing Water, Depending on Your Budget

If you worked as a brewer at Sierra Nevada Brewing circa 2005, you would have had the luxury of deaerating the brewing water with an expensive deaerating column to reduce the amount of dreaded dissolved oxygen (DO) in your cold side processes.

Scott Jennings, innovation brewmaster at Sierra Nevada, worked there at the time. He says, “The benefits of a column system for water deaeration is that such a system removes oxygen from the water to a very high degree ( <5 ppb oxygen ), the water is sterilized in the process, and the water can be carbonated afterwards if that is desired.”

Today, the column remains a gold standard of deaeration equipment and still lingers out of most brewers’ budgets. While the majority of independent American breweries either opt for somewhat less cap-intensive systems or bootstrap with boiled water and carbon dioxide (CO2), many small brewers don’t deaerate their brewing water at all.

That’s a mistake, cautions Grant Wood, former head brewer at Boston Beer and co-founder of Revolver Brewing in Texas.

“Most (cold-side, prepackaging) DO issues arise from poor seals on pumps and fittings. Packing the lines with deaerated water before the beer, and pushing with deaerated water to clear the lines to the tank are the primary ways to reduce DO and protect the beer,” he says.

Russian River Brewing co-owner Vinnie Cilurzo agrees, “Because the DAW (deaerated water) will completely flush the transfer line it is a superior way to remove oxygen.”

The science to deaerating water relies primarily on a principle called Henry’s Law, explained by a paper published in August by the National Center for Biotechnology Information as: “When a gaseous mixture is in contact with a solution, the amount of any gas in that mixture that dissolves in the solution is in direct proportion to the partial pressure of that gas.”

So in order to virtually eliminate the amount of oxygen in a gaseous mixture, write the co-authors of the Brewers Association’s book Water: A Comprehensive Guide for Brewers, “The ratios of the partial pressures (of the gases) must be shifted so that the partial pressure of oxygen is as small as possible. This can be accomplished by increasing the partial pressure of another component gas to offset it, by increasing the vapor pressure of the water, or by reducing the total pressure of the system.”

Brewers can keep their beer as oxygen-free as possible by chasing it away with deaerated water at myriad points in beer making, including: purging pipes, filtration systems, centrifuges and can/bottle fillers; diluting the ABV of high-gravity brews; and cleaning in place.

There’s a deaeration method for every budget. Here are a few of the most common:

Column Deaerator $$$$$

A tall column is filled with structured packing material (Denwel, for example, uses stainless steel) with a high surface level to provide maximum contact area between the water and stripping gas — CO2 or gaseous nitrogen (N2). In Denwel’s model, water fills the column from the top while CO2 or N2 gets injected from the bottom.

Where the stripping gas and water meet, the pressure of the gas proportionally reduces the pressure of the DO in the water. The CO2 or N2 dissolve while the scrubbed oxygen becomes less soluble and vents out through a valve at the top along with any residual stripping gas.

Both cold and hot water column systems exist, with hot water typically exceeding the results of its cold water sibling. Kaminsky and Palmer present low energy consumption, high flow rates and low maintenance as advantages to columns.

Vacuum/Membrane Deaerator $$$$

In a typical vacuum deaerator, stripping gas enters a water tank — often filled with material to increase surface contact area — then is vacuumed out with enough force to boil the water and expel DO and any remaining CO2 or N2. The membrane version fills the many microporous, hydrophobic fibers that comprise the membrane with stripping gas that then get sucked out by vacuum. Outside the fibers, the water flow creates a counter current and the differential between the partial pressures of the stripping gas and O2 forces the oxygen out of solution.

“At Revolver Brewing, we used a membrane system from Powerflow that uses 3M membrane technology. It’s small, simple to use and effective,” says Wood. “We had some help from the engineering team at Molson Coors (which bought Revolver in 2016). They had vetted the device for small production use.”

“We have had our DAW plants in place for many years and rely on them for efficient, low-cost and on-demand production of DAW in our breweries,” adds New Belgium Brewing brewmaster Christian Holbrook, who’s currently working with a vacuum system.

DAW Feedwater Skid $$$

Both Cilurzo and Bell’s Brewery packaging quality manager Tim Lozen rely on feedwater skids for their DAW. A feedwater skid is a contraption that mounts or structurally supports a water tank atop of a deaerator of some type to continuously feed water through the machine.

It provides “DAW on demand,” Lozen says.

“If I was starting out from scratch with a new brewery I would at least plan for a future DAW skid,” says Cilurzo. “I would also build into the brewery an extra brite beer tank that can be used to make batches of DAW.”

A feedwater deaerator works inline as the water is moving through the system into a holding tank. The stripping gas, CO2 or N2, is broken down to tiny bubbles and injected into a moving stream of water. As the water exits the injection section and into the holding tank, O2 is vented out along with the stripping gas.

Dr. Murthy Tata of QuantiPerm says his company’s automated xFlow technology is designed to ensure consistent bubble breakdown to use as little gas as possible. Additionally the holding tank contains a vacuum to more thoroughly evacuate the stripping gas and leave behind DAW with ≤10 ppb of O2.

Tata emails, “Feedwater deaerators, when designed correctly, tend to provide savings in the short term (gas usage) as well as long term (no membranes or columns to maintain).”

Boiling and Adding Stripping Gas ($)

“The easiest way to make DO-reduced water is by boiling. Boiling drives out dissolved gasses,” says Wood. “Then cool the water and purge with CO2 to remove any remaining DO.”

This DIY approach is how most brewers make do. Before Bell’s got its skid, Lozen recalls, “We were filling a smaller tank (50bbls) with water, and bubbling CO2 through it from the bottom. We would check the water at regular intervals with a portable DO meter until we got to single digits.”

“We sanitize the water, cool it down then carb it – boom, deaerated H2O!” emails brewer Daytona Camps from Celis Brewery in Austin. She says the water and CO2 costs present drawbacks but, “The result is worth it.”

To top