Why Glycol At All?
Water is a great heat transfer fluid — but it freezes at 32°F (0°C). If your process needs cooling below that, or if there is any risk of your pipes getting cold enough to freeze in winter, you need to add glycol to your loop. Think of it like antifreeze in your car: it does not just prevent freezing, it also raises the boiling point and protects against corrosion.
Two Types: Which One Do You Use?
Propylene Glycol — Food Safe
This is what you use in breweries, wineries, food processing, and anywhere your fluid might come into contact with a product that people eat or drink. Propylene glycol is non-toxic and biodegradable. It is the default choice for food and beverage.
Ethylene Glycol — Industrial Only
Ethylene glycol works a bit better thermally but it is toxic. Use it only in industrial systems with no food contact risk. Never use ethylene glycol in a food or beverage facility.
How Much Glycol Do You Need?
The more glycol you add, the lower the freezing point — but also the less efficiently your fluid carries heat. You do not want more glycol than necessary. A common rule: set your glycol concentration so the freeze point is about 10–15°F below your coldest operating temperature.
| Glycol amount | Freeze protection (PG) | Typical use case |
|---|---|---|
| 30% glycol, 70% water | Down to about 9°F (−13°C) | Most breweries and wineries |
| 40% glycol, 60% water | Down to about −7°F (−22°C) | Cold stabilization, deeper chilling |
| 50% glycol, 50% water | Down to about −28°F (−33°C) | Sub-zero process cooling |
What This Means for Chiller Size
Glycol does not carry heat as efficiently as water. A 30% glycol mix carries roughly 85% as much heat as straight water at the same flow rate. That means if your calculation assumed pure water, your actual chiller needs to be a bit bigger to compensate. Not dramatic, but worth accounting for.
Do Not Forget the Loop Design
A well-sized chiller can still underperform if the pipes carrying the glycol are too small. Small pipes create resistance that slows down flow, which means less heat gets removed per minute. The chiller, pump, and piping need to be designed as a system, not just the chiller in isolation.
Remember: Food and beverage always means propylene glycol. No exceptions. If someone suggests ethylene glycol for your brewery, politely decline.
FAQ
Propylene or ethylene glycol?
Propylene glycol for anything food or beverage — it's food-safe. Ethylene glycol is toxic and only belongs in fully isolated, non-food loops.
How much glycol do I need?
A 30% propylene-glycol mix (freeze protection to about 9°F) covers most breweries and wineries; go higher only if you need deeper cold.
Still Not Sure What You Need?
Tell us what you are cooling and we will figure out the right chiller for you. No jargon, no catalog. Just a straight answer.