Microbrewery and larger breweries commonly use Propylene Glycol USP as a cooling refrigerant fluid. USP certified Propylene Glycol is required in cases of accidental beverage contact. Here are a few more things you must know:
Do you want premixed or concentrated Propylene Glycol USP? Purchasing premixed Propylene Glycol USP solution
is the easiest way of purchasing your solution. You simply determine your dilution rate and order the volume required. This option is more expensive, becuase you are paying for water
transportation. Option 2 is you purchase concentrated Propylene Glycol USP and dilute the glycol with water that is less then 120 ppm in hardness.
What dilution rate do you need your Propylene Glycol USP diluted to?
Check with your chiller manufacture for their dilution rate
recommendations. Common dilution rates are 20 to 40% dilution rates.
Keep in mind the higher the Propylene Glycol USP ratios, the higher the
solution viscosity, and thus the more your chiller will work. That is
your chiller pumps will consume more energy and at times may failure
What are the metals in you glycol chiller system? If you have iron or a lot of low grade of stainless steel, you may require a food grade corrosion inhibitor with your Propylene Glycol USP Solution. You will require 1 gallon of ADPAC per 35 gallons of concentrated 99.9% Propylene Glycol USP within the water system. If your system is all stainless steel, CPVC, and copper you may choose to use just straight Propylene Glycol USP and premix. You may not require a corrosion inhibitor. This is your choice. In some cases, some existing Brewery chillers were not installed with no corrosion inhibitor. Instead of dumping the system and refilling it, you may just purchase the corrosion inhibitor into your water system. Some chillers specify DowfrostTM Propylene Glycol. DowfrostTM is a 96% solution of USP grade corrosion inhibited Propylene Glycol solution. It is approved for use in USDA and FDA plants. If you require DowfrostTM, simply order directly online your premixed solution or concentrated version. DowfrostTM is a trademark of Dow Chemical.
Do you have a glycol refractometer to verify solution rates? A hand held glycol refractometer is easy to use. Simply grab a sample, insert it on the slide, and hold to the light. You can record the freeze point.