The Importance of the Cooling and Glycol Water Chiller in Your Craft Brewery

Your cooling and glycol systems, better known as a water chiller, is the most important piece of equipment in your brewery. Why? First, there is no other single piece of equipment directly or indirectly involved in so many steps in the process of making beer.  While milling, mashing, lautering, and boiling are hard concepts to connect with the chiller system, the heat added during these processes is removed by the chiller. One of my favorite analogies is: “The Boiler is the gas pedal and the chiller system is the brakes."

Let's examine the steps of the beer making process to see how glycol is used along the way.

Wort Chillers and Glycol

The CLT is typically a stainless steel water tank with cooling jackets or an external heat exchanger.  The CLT is filled with water that is chilled between brewing cycles to a temperature around 35 F. This cold water is then pumped through the wort exchanger at a 1:1 ratio, cooling the wort from post boil temperature to the desired fermentation temperature. The exiting water, (now 140-160 F) is transferred to the hot liquor tank to be utilized for the next batch of beer.  The CLT is often sized to hold enough cold water to service a typical 24-hour brewing cycle. For example, if you have a 15 Bbl brewhouse, and will typically brew three times per day, the CLT would be sized at 45 Bbl.

Quick fact: this heat load is tremendous when compared to the other cooling loads the chiller system services. Often this will require the brewer to isolate their cellar from the cooling loop, so all of the available cooling capacity of the chiller system is dedicated to this single process.

This is a great lower cost option for breweries that experience a seasonal spike in city water temperatures, but the rest of the year are able to adequately cool the wort. A lower cost brazed plate stainless steel heat exchanger is used with the drawback that these welded heat exchangers can’t be opened up to clean and if they become fouled or plugged, often a new heat exchanger is needed.

Deciding which option is best depends on several factors: average water supply temperature, your brew schedule, the styles of beers that you brew, and your future growth plans.  I’d suggest talking to other brewers in your size range and in your region. Seek advice from your chiller supplier, they will be glad to help evaluate the options with you.

Next in the process is fermentation. Wort is in the fermenter, the yeast is pitched, and the fermentation process begins. Using cooling jackets on the fermenter, chilled glycol enables the brewer to maintain ideal fermentation temperatures throughout the process.

For the most common Ale Style Beers, a majority of the heat of fermentation is generated quickly, when we estimate the cooling loads for a brewery we actually calculate the heat load using the assumption that all of the heat is generated in the first 72 hours of fermentation.

There are a number of formulas to calculate the heat of fermentation, we use a factor of 15 bricks per Bbl which is then multiplied by 280 BTU per brick.  We divide the load across 72 hours to determine an estimated BTU/HR to determine what kind of capacity we will need from the chiller to service this step.

After crash cooling, the beer is held allowing solids to drop, the beer to clarify, before being transferred to a conditioning vessel and then perhaps to packaging or serving vessels.

The air conditioning cooling load is very small, we are simply keeping cold beer cold. To calculate we take the total square foot surface area of the vessel, use a factor that estimates the heat loss through the vessel insulation and factor total temperature difference between conditioned beer and the average cellar temperature.

48 F TD is then multiplied by the SF Factor of 45 = 2,160 BTU/HR Cooling Load

Packaging is often the next step. Because bottling and canning lines can be very finicky, a plate heat exchanger can be installed at the bottling/canning line. Any heat picked up during the transfer from the brite tank is removed, insuring a steady flow of beer at a consistent temperature.  

Cold room cooling with chilled glycol is becoming more common versus a traditional direct refrigerant based system. To be clear, using chilled glycol isn’t more efficient, at best this concept is equal, or even slightly less efficient. So why go this route? The benefits are reduced installation costs, simplified control and operation, and the elimination of an additional refrigeration system. Chilled glycol requires a larger coil surface because the glycol coil temperatures are higher than traditional refrigerant coil temperatures. Higher coil temperatures remove less air moisture from the room which allows a higher condensation factor- especially when warmer product is brought into room and pull down cooling is required of the product.

We use a program to estimate the cold box cooling load developed by a cold room box manufacture. To calculate, we take the dimensions of the room, including ceiling height, and factor if the load is simply “holding” product at temperature or a “pull down” of the product is required and needs to also be factored.  

There’s numerous other cooling loads I’m omitting. I do want to mention centrifuges, which can cause a 3-4 F temperature rise in product exiting the centrifuge, this heat is then removed in the brite tank or the packaging heat exchanger. Often this load is overlooked.

Your cooling and glycol water chiller accepts that it is going to have a pretty thankless existence. It understands it will likely spend its life living behind the brewery, to have stuff stacked on and around it, or it might even live on the roof where it won’t see anyone for months at a time. Your chiller system loves it when it gets to see the maintenance technician monthly to have its glycol percentage tested, to have the pressures checked, and maybe a quick cleaning of the air cooled condenser. Unfortunately, sometimes it will need to see its Doctor, or Service Technician, and it is as disappointed as you are when this happens at 3:30 on a Friday afternoon-  but your chiller system hopes these visits are rare and that you understand the more visits it receives from the maintenance department, the fewer doctor visits will be required. 

Your water chiller system never asks a day off and although it might spend much of its time patiently waiting for a cooling demand, when it’s called into action, it is ready to go to work during the heat of summer and through the extreme cold of winter.