Introduction to Glycol


Glycol Chillers


Glycol Systems and Crafting the Perfect Beer

Brewing beer from scratch is an art form. It lets you showcase your attention to detail as well as your creativity, especially when considering your preferred method. Any good brewer knows that you need complete temperature control during the fermentation process lest you ruin a perfectly good batch.
One of the most effective ways brewers have maintained temperature levels is through efficient cooling methods. Utilizing glycol as refrigerant, these systems allow crafters to regulate temperatures while keeping their precious potions safe from contamination. In order to get the most benefit from these brewing setups, there are quite a few things you’ll need to keep in mind.

The Right Kind of Glycol

Not all refrigerants are the same, especially when it comes to food production. Since glycol is basically an antifreeze, it comes as no surprise that it’s the primary refrigerant in the kind you’ll find in vehicles. This form of compound is called Ethylene Glycol and is extremely toxic and shouldn’t be used in any type of food preparation.
When brewing your favorite craft beer, you’ll need USP grade PROPYLENE GLYCOL, the type used in breweries across the world. With a seal of approval from the United States Pharmacopeia, an institution devoted to ensuring chemicals used in medicine, food prep and health care methods, you can be assured it’s of the highest quality.
Take note of where you get your supply, because while cheaper forms of propylene glycol are available they may not be certified as usable by the USP. These aren’t designed for the intensity inherent to the brewing process and could damage your equipment. In addition, if your system uses components that can rust you’ll want to check the Safety Data Sheet (SDS) for rust inhibitors.

When to Cool

While there are a variety of methods used in homebrewing beer, there are some that rely on cooling solutions with glycol additives. From cooling the wort to refrigerating your kegs, propylene glycol will help make sure temperatures stay at desired levels.
  1. Wort production: Many pro brewers use two stage wort chillers. One of the stages in the heat exchanger could be one of your glycol loops or a line from a cold liquor tank that is chilled via your glycol chiller. 
  2. Fermentation: During this step, yeast will begin to consume sugars and release heat as a result. Like an anxious driver flooring the gas pedal, this can lead to overheating during the process. USP grade glycol will help put on the brakes, letting you have better control of internal temperatures and fermentation as a whole, and giving you more quality control over your beer.
  3. Packaging: Some brewing aficionados prefer cold-room cooling with glycol over a direct refrigeration method. While this has no clear advantages, it can have a lower installation cost and let you utilize a refrigerant you already have in supply.
While cooling systems aren’t essential for all aspects of the brewing process, it is beneficial to have devices on hand that will tackle these jobs in case unforeseen circumstances. A heat wave, for example, could have drastic effects on fermentation, leading you to require some form of cooling even if it’s a temporary condition.

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Enough Is Enough

To save on costs, you’ll want to make sure that you use a proper mix of glycol and water when setting up your cooling system. Too much glycol will leave you with a freezing point far below what’s necessary while wasting funds on refrigerant. Too little, and you risk the entire system freezing, leaving the fermentation process to proceed unchecked!
Remember that the freezing point in your system will rest around 10 to 15° F below your mixed glycol solution. Therefore, if your chiller is set to 27° F, you should expect the freezing point to fall around 7° to 2° F. Also keep in mind that the more refrigerant is added, the freezing point will drop exponentially, like so:
  • 0%  glycol = 32° F freezing point
  • 10% glycol = 26° F freezing point
  • 20% glycol = 18° F freezing point
  • 30% glycol = 7°  F freezing point
  • 40% glycol = -8° F freezing point
  • 50% glycol = -29°F freezing point
Traditionally, a 35% glycol mix will be most effective, keeping the freezing point steady, making it well-suited for cold environments. Check your manufacturer's indicated burst point on your equipment as well. A burst point is the temperature at which the equipment becomes vulnerable to pipe/gasket swelling to the point of failure, which damages machinery and contaminates the beer.

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System Shock

It;s important to take a few things into consideration when setting up a USP grade glycol system. Since homebrewing often attempts to mimic commercial brewery designs but on a smaller scale, it helps to look at how corporations lay out their own operation. Piping, for example, coomes in several different varieties.
  • Copper: A durable, tried-and-true material, though it can be expensive
  • Nylon-braided rubber hose: Excellent for lighter applications, this is a perfect homebrew option
  • Pre-insulated schedule 80 PVC: an inexpensive alternative, but requires close attention during installation
  • ABS plastic: Made specifically for water-cooling applications, it’s a top choice, but also has a higher price tag
Once you’ve determined what piping you’ll use, it’s time to look at different layouts for your fermentation and conditioning tanks. Try to keep your setup as simple as possible to limit places where propylene glycol can build up, like joints and connectors. In addition, placing coolant systems nearer to your tanks will not only reduce installation costs but increase efficiency since coolant will have less time to heat up on transit.
A “first-in-last-out” standard works well in most situations, meaning the first line to leave the system is the last to return for cooling. Check for a bypass valve and install it if your current system lacks one, while also ensuring that each tank has a temperature-controlled solenoid valve as well to prevent mishaps. 
Homebrewing beer is both rewarding and fun, especially if you enjoy designing systems that work at peak efficiency. Make sure you follow proper procedures when working with cooling systems, and use only USP glycol to keep your equipment working at top performance. This will have you worrying less about the process and focusing more on brewing your best craft beers!

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