Winery Chillers commonly use Propylene Glycol USP to maintain proper operation at lower freeze points. The items you must consider prior to order Propylene Glycol USP are:
Do you require a corrosion inhibitor? If you have extensive iron or copper and desire to minimize corrosion rates, you need a food grade USP grade Propylene Glycol. ChemWorld offers you two options. Propylene Glycol USP and Dowfrost, or any USP grade corrosion inhibited Propylene Glycol solution. These products can be order in concentrated (96% Solutions or in premixed solutions). If you do not need a corrosion inhibitor or you have an all stainless steel operation, straight Propylene Glycol USP is sufficient
What temperature do you require your system to drop to? Wineries typically know the temperature range they require there solution to be protected to. If you do not, check with your manufacture or your processing engineer. Typically, we find wineries to run between 20 to 40% solutions of Propylene Glycol solutions.
Do you want premixed Glycol or do you have good city water on site to mix it your self? Purchasing concentrated Glycol is the cheapest way. Diluted Propylene Glycol means you are paying for water to be mixed into the solution and you are paying on additional freight to move water. If you have water that is below 120 ppm in hardness you can this water to mix your Propylene Glycol Solution. Deionized water or distilled water will also work.
Is bacteria development in your Propylene Glycol solution a concern? If so, maintain your solution above 40%. A 40% Propylene Glycol solution will minimize bacteria development in your process glycol solution.