DIY Glycol Chiller by Matt Smith

DIY Glycol Chiller: Master the Art of Cooling [Step-by-Step Tutorial]

I don’t know about you, but a nice cold beer on a warm summer’s day is one of the best things in life! Making great beer requires precise temperature control, which is made possible with a homebrew glycol chiller.

Temperature control during the process of beer fermentation is crucial in keeping the consistency of the flavor you want to achieve.

Buying the high-end Icemaster or SS Brewtech chillers would be an ideal investment. But in case this is off your budget, we’ve written this article to help you build your own DIY glycol chiller.

What is a Glycol Chiller?

Special cooling systems that use food-grade propylene glycol as an anti-freeze agent.

This particular chemical removes the excess heat produced from the process of brewing beer, then breaks off this heat to the refrigeration system. As a result, specific temperatures are maintained, providing the highest quality final product.

You’ll find a glycol cooler useful with worts, brite tanks, fermenters, and heat exchangers. These are used in the brewery industry, mainly, but not limited to the production of beer and whiskey. You can brew ciders and kombucha too!

How do Glycol Chillers Work?

Supercooled glycol is circulated in a closed glycol system. This comprises tubing that connects to the input and output parts of the chiller unit and heat exchanger.

Propylene glycol’s freezing point is at -74.2°F or -59°C. Glycol/water mixtures have a more moderate freezing point. Thus, it is often preferred by breweries. It cools wort much faster without producing ice inside the brewing vessels that could cause damage.

A glycol/water solution gets to dissipate huge amounts of heat quickly. This regulates temp and creates stable chemical reactions. It can also keep away algae from developing in your brewery equipments.

Why a Glycol Chiller DIY?

I hate to break it to you, but commercial chillers are damn expensive. Price tags start from $1,000 and go up depending on capacity.

You’ll also spend on the glycol chemicals to actually put the chiller to good use. Brewers mix a percentage of glycol and water for better outcomes and lowered costs.

Apart from that, other equipment and materials like a jacketed vessel and coils are also needed to get the whole system running. There are other means to cool your batches of brews. The old school method is to run water and add ice packs in a freezer containing your brews. It is, however, challenging to control as compared to using a chemical like glycol. It’s also a tedious process of constant draining of water.

When you’re starting a brewing company or just at an avid homebrewer, making your own glycol chiller would be a feasible project. It may not be as easy peasy, but it can save you a lot of bucks and time. You can make one with a budget of just around $200!

What You Need

In essence, a chiller is a fridge. It should include a compressor, evaporator, condenser, and a temp control function. In this regard, an AC unit is your best alternative.

A portable type AC unit is preferred because they have exhaust hoses that allow you to draw the heat produced out to your window. This avoids unnecessary heating to your home. Although, a window-mounted AC unit can still do the trick.

Commercial chillers start at 2,300 BTU/hr. They are built more efficiently than your DIY version. In this case, at a minimum, you should get an AC unit with 5,000 BTU/hr. The more products you need to chill, the higher the BTU capacity you need.

Next is to have a large container. Lower budget Coleman beer coolers are often preferred. The size will depend on the quantity of the brew batch you need to cool. You will also need pumps, tubing, plywood, paint, insulation foam, and casters to assemble and keep the whole thing together.

Lastly, have your food-grade propylene glycol mixed with distilled water. Proportions will depend on your preference and testing.

Steps To Making Your Own Glycol Chiller

Do you have all the materials listed above? Here are 8 steps to making your own glycol chillers at home:

Step 1: Tear the AC unit apart.

Remove the AC unit outer casing where you will find the evaporator and condenser exposed. These are the parts necessary for the movement of heat.

Step 2: Disconnect the thermostat.

We need to make sure your AC unit keeps running on ultracold and fan on high.

To do this, you’ll have to disassemble the thermostat from the electronics housing. Take the two red wires from the thermostat and wire them together with electric tape.

In this case, in order for us to control our desired temperature from now on, plug everything into an external Inkbird temp controller.

Step 3: Unbolt the fans.

The evaporator has a fan that will be of no use. Take it out to create a better working space.

The condenser, however, also has a fan which we will need for the AC unit to work. Do not remove this.

Be extra careful as these motors run on heavy voltage.

Step 4: Bend the copper tubings and fit the condenser in your cooler.

This is perhaps the most critical part of this process. Be wary, so work slowly and carefully.

Manipulate your condenser by slowly bending the copper tubings, fitting the cooling fins into your cooler.

Watch how moving a piece at a time affects another piece of copper. We want to make sure there are no problems with the tubing, as copper bends quite easily. This step could be irreparable!

Step 5: House the Glycol System.

Get a hold of some plywood to box your AC unit and cooler up. Make sure to place one or two vent cutouts for airflow too.

After everything is placed accordingly in its position, fill the gaps with insulation foam to better control the temperature.

Creating a good fitting housing, installing casters and handles will aid in maneuvering the whole thing around when connecting with the fermentors. Enclosing one makes it look cleaner too.

Step 6: Cut holes for the glycol hoses.

With a hole saw and a jigsaw, cut holes at the top of your cooler for the glycol lines to run to the fermentors as well as exit the chiller.

Wrap the glycol hoses with insulation foam to prevent sweating.

It also helps hold things together and prevent your water and glycol mixtures from splashing. Reinforce them with duct tape.

On the fermentors, establish tubing connectors too.

Step 7: Load your glycol and water mixture.

You don’t need to go extensively cool to maintain ideal temps for fermentation.

Glycol can lower the freezing point, while water can keep heat capacities high enough out of the fermentors to function efficiently.

You can have a 1:2 ratio for glycol to distilled water to start with.

Step 8: Plug things in.

At this point, you should have a full functioning chiller. Use your temperature controller to set up your unit’s temps.

To get a good fermentation temperature, initially set your unit to 5°C or warmer. This makes sure you don’t shock your beer when it starts to cool.

For cold crashing, use temp of -1/-2°C. We suggest you to test the waters first and see where it goes. One must take precautions and see what works best for you.

If you hear any unusual hissing signifying any broken parts or a leaking refrigerant, take the unit outside your house and call a professional. This could be very flammable and dangerous to your health once inhaled.

Important Tips

  1. Insulate the parts that get cold. These are the fermentors, glycol lines, and cooler. This will avoid sweating, provide better stability for the structures, and in essence, extend the lifespan of your unit.
  2. Use a pump in the cooler to help recirculate the glycols on the evaporator when the AC unit is switched on.
  3. Never use automotive anti-freeze chemicals. These are manufactured specifically for engine cooling only. As mentioned earlier, only food-grade glycol should be used for brewing temperature controls.
  4. Never mix different glycol types or brands. One may be incompatible with the other. This can lead to formula separation that clogs the pumps.
  5. Preferably, use inhibited glycols too. These work as a pH buffer and a biocide. It protects your equipment from extreme corrosion. Go for 25% and above glycols.
  6. Make sure to vent the heat from the AC unit in use outside your working space.
  7. Always check any leaks or hissing sounds. In case you detect any damages, call a professional to have it fixed.
  8. Consider your local environmental rules and regulations with regard to antifreeze solutions. Structure, drainage, and disposal are some to prepare for properly.
  9. Most systems just use tap waters. If you want to extend the unit’s lifespan, we advise you to use the purer waters. Distilled, demineralized, and de-ionized water choices protect your units.
  10. For maintenance, it is greatly encouraged that you flush, clean, and sanitize your chilled water systems before you add a new solution and batch. This should also be tested from time to time to avoid any contaminations or corrosion issues.


One may get intimidated by the idea of building one’s own glycol chiller. Working on a $200 budget as compared to going for the commercially made ones over $1,000, makes this definitely worth giving a shot. Who knows, you might surprise yourself!

We hope our guide will help you get your way around to this unique “Do It Yourself” project for your home breweries. Share your experience with us.

Frequently Asked Questions

How to Add Glycol to a DIY Chiller?

Adding glycol to a DIY chiller involves a few steps. First, you’ll need to prepare a mixture of food-grade propylene glycol and distilled water. The ratio can vary, but a good starting point is a 1:2 ratio of glycol to water.

Once the mixture is ready, you can load it into the large container that forms part of your chiller system. Make sure to use tubing connectors on the fermentors to establish a closed glycol system.

What Size Glycol Chiller Do I Need for Homebrewing?

The size of the glycol chiller you need depends on the quantity of brew you intend to cool. Commercial chillers start at 2,300 BTU/hr, but for a DIY version, a minimum of a 5,000 BTU/hr AC unit is recommended.

The more products you need to chill, the higher the BTU capacity you’ll need. Budget-friendly options like Coleman beer coolers can be used as the container for your glycol solution.

How Does a Glycol Refrigeration System Work in Brewing?

In a glycol refrigeration system, supercooled glycol circulates in a closed system comprising tubing that connects to the input and output parts of the chiller unit and heat exchanger.

The glycol removes excess heat produced during the brewing process and transfers it to the refrigeration system.

This helps maintain specific temperatures, ensuring a high-quality final product. Propylene glycol is often used because of its low freezing point and ability to cool wort quickly without causing damage.

Why is Glycol Used for Cooling in Brewing?

Glycol is used for cooling in brewing because it has a low freezing point and can dissipate large amounts of heat quickly. It is also food-grade and safe for use in brewing applications.

Glycol helps in maintaining the desired temperature during the fermentation process, which is crucial for achieving consistent flavor. It also prevents the formation of ice inside brewing vessels, which could cause damage.

How to Make a Glycol Chiller at Home?

Making a glycol chiller at home involves several steps and requires various materials like an AC unit, a large container, pumps, tubing, plywood, paint, insulation foam, and casters.

The process includes tearing apart an AC unit, disconnecting the thermostat, unbending copper tubings, housing the glycol system, and finally loading your glycol and water mixture.

The DIY approach can save you a lot of money, as commercial chillers can be quite expensive. With a budget of around $200, you can build your own glycol chiller for homebrewing.

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