How To Size A Glycol Chiller For Your Brewery August 4, 2026 Chiller sizing is where good brewery cooling design either succeeds or fails. Too small, and you can't hold fermentation temperatures during peak load. Too large, and you waste money on equipment and fight efficiency problems from oversized systems running at low partial load. Getting it right requires working through the actual thermal loads, not relying on rules of thumb alone. The Basic Thermal Load Calculation Every heat load in the brewery that your glycol system must manage contributes to required chiller capacity. The main sources: Fermentation heat: yeast activity generates heat during active fermentation. Typical values range from 8-15 BTU/hr per gallon of active fermenting wort, depending on yeast strain, nutrient levels, and fermentation temperature. Heat conduction through tank walls: even well-insulated tanks lose (or gain) heat to the environment. Calculate based on tank surface area, insulation R-value, and temperature differential to ambient. Glycol line heat gain: exposed glycol piping picks up ambient heat between the chiller and the tanks. This is often underestimated, especially in warm mechanical spaces. Wort chilling (knockout): if your glycol system is used to cool hot wort post-boil, that's a large, intermittent load. Calculate peak knockout load separately. Worked Example: 15-Barrel Brewery Load Source Load (BTU/hr) Notes Fermentation heat (3 active tanks x 465 gallons x 12 BTU/hr/gal) 16,740 Simultaneous peak assumption Cold conditioning tank (1 tank at 32 F in 70 F ambient) 3,200 Constant load; often underestimated Glycol line heat gain (estimated) 1,500 Depends on pipe length and insulation Brite tank (1 x 15 bbl at 32 F) 2,400 Safety margin (20%) 4,768 Total required capacity 28,608 BTU/hr = 2.4 tons; round up to 3-ton minimum unit Example values are illustrative. Actual loads depend on yeast strain, ambient conditions, insulation quality, and batch schedule. Always validate with a detailed calculation before equipment selection. Glycol Concentration and Temperature Glycol concentration affects both freeze protection and heat transfer efficiency. More glycol improves freeze protection but reduces heat transfer capacity and increases pumping energy. Standard recommendations: 25% propylene glycol: freeze point approximately 8 degrees F; adequate for most brewery glycol temperatures above 25 degrees F 30-35% propylene glycol: freeze point below 0 degrees F; appropriate for systems targeting 26-28 degrees F glycol supply Avoid over-concentration: glycol above 40-50% degrades heat transfer significantly and isn't necessary for typical brewery applications "Chiller sizing for a brewery isn't just about the beer you're making today — it's about peak scenarios. The day you have three tanks at high krausen simultaneously in an August heat wave is the day that matters most."— Paul Johnson, G&D Chillers Accounting for Wort Knockout If your glycol chiller serves the wort chiller as well as tanks, the knockout load requires special attention. A typical knockout — chilling hot wort from 170+ degrees F to pitching temperature over 45-90 minutes — can represent a load many times larger than your steady-state tank load. Options: Size the chiller to handle knockout load (expensive; often oversized for routine operation) Use municipal cold water for the first cooling stage, then glycol only for the final cool (most common in commercial-scale breweries) Install a glycol storage tank (buffer) to allow the chiller to pre-cool a glycol reserve that handles knockout demand Frequently Asked Questions Should I add extra capacity for future expansion? Yes, if expansion within 3-5 years is realistic. Adding 25-30% capacity buffer at initial installation is far cheaper than replacing the entire chiller system when you add tanks. Discuss planned growth with your chiller vendor before finalizing size selection. What happens if my chiller is slightly undersized? The most common symptom is inability to maintain fermentation temperature during peak simultaneous load — multiple tanks active at once, in warm ambient conditions. This typically first appears in summer and can result in temperature excursions that affect flavor or require adjusting batch schedules. > Get a chiller sizing calculation for your specific brewery setup -> Contact us