Glycol Chiller Maintenance For Breweries: Keeping Your System Running Clean August 4, 2026 A glycol chiller is one of the most critical pieces of equipment in a production brewery — and one of the most neglected. Because glycol systems tend to run continuously without obvious symptoms of developing problems, maintenance is easy to defer. The consequences of that deferral range from gradually degrading fermentation temperature control to sudden chiller failure during a critical production period. Why Brewery Glycol Systems Need Special Attention Brewery glycol systems have characteristics that make them particularly prone to specific maintenance problems: Propylene glycol degrades over time: heat cycling and exposure to metals cause glycol to break down, producing acids that corrode piping, heat exchangers, and chiller components. Untreated degraded glycol is a system-damaging fluid. Contamination risk: glycol loops that contact wort or beer (through a leaking heat exchanger or cross-connection) require immediate flushing and testing before food-safety issues develop Biofilm growth: glycol, especially at warmer temperatures in return lines, can support microbial growth that clogs strainers and reduces flow Maintenance Schedule: What to Do and When Task Frequency Visual inspection — chiller operation, no alarms, glycol level in reservoir Weekly Strainer inspection and cleaning Monthly Glycol concentration check (refractometer) Quarterly Glycol pH test (target 7.0-8.5) Quarterly Chiller condenser coil inspection and cleaning Quarterly (monthly in high-debris environments) Refrigerant circuit check — superheat, subcooling, visual leak inspection Annually with service provider Full glycol sample analysis (inhibitor levels, metals, microbial) Annually Complete glycol flush and recharge Every 3-5 years or when pH drops below 6.5 "The glycol loop is the circulatory system of the brewery's cooling infrastructure. Neglecting it is like ignoring your oil changes — it works until it doesn't, and then it fails at exactly the wrong time."— Andy Backer, VP of North American Sales, G&D Chillers Glycol Testing: What to Check and Why Concentration: measured with a refractometer; ensures adequate freeze protection and heat transfer capacity pH: degraded glycol becomes acidic; acidic glycol corrodes copper and aluminum heat transfer surfaces Inhibitor levels: fresh glycol contains corrosion inhibitors that deplete over time; testing confirms whether inhibitors are still active Metals testing: elevated copper, iron, or aluminum in the glycol indicates active corrosion — a signal to investigate and correct before major damage occurs When to Flush and Recharge Complete glycol replacement is necessary when: pH falls below 6.5 (acidic glycol; corrosion is occurring) Inhibitor levels are depleted and cannot be restored with additive treatment Contamination with beer, wort, or cleaning chemicals has occurred Heavy microbial growth is present in the loop The system is 5+ years old without prior flushing Glycol flush and recharge with fresh inhibited propylene glycol is typically a one-day service operation. The cost is minimal compared to the cost of corrosion damage to chiller heat exchangers or fermentation disruptions from system failure. Frequently Asked Questions Can I test my own glycol or do I need a service provider? pH and concentration can be checked with inexpensive test equipment available at brewing supply companies. Full inhibitor and metals analysis requires a laboratory sample kit, which can be ordered from glycol suppliers. Annual full-panel testing is best performed by a lab or service provider. What do I do if my glycol pH is too low? Acidic glycol can sometimes be buffered with inhibitor additive if caught early and pH isn't severely depressed. If pH is below 6.5, complete system flush and recharge is typically the correct approach. Testing the piping and heat exchangers for corrosion damage before recharging is advisable. > Schedule a glycol system inspection with G&D's service team -> Contact us