What coil length do I need?

For a standard 23L batch, a 7.5-10m coil of 10mm copper tubing works well. Longer coils provide more surface area and faster cooling, but eventually the gains diminish as the water heats up along the coil.

Yes, gently stirring the wort or whirlpooling during chilling dramatically reduces cooling time by preventing a hot layer forming around the coil. Some brewers use a pump to recirculate.

How can I reduce water usage?

Recirculate through an ice bath, use a pre-chiller coil in ice water before the main chiller, or collect cooling water for cleaning and garden use. Stop tap water once within 10°C of target and switch to ice water.

Copper or stainless steel?

Copper has far better thermal conductivity (~385 W/m·K vs ~16 W/m·K for stainless). However, stainless is more durable and easier to maintain. For chilling performance, copper is significantly faster.

How can I improve immersion chiller performance?

Use the coldest water available (pre-chill with ice), stir the wort gently during cooling, use larger diameter or longer coils, and connect two chillers in series. Pre-chilling the cooling water with an ice bath before it enters the chiller can significantly speed cooling.

BrewCalcs

Immersion Chiller Calculator — Brewing Equipment

Calculate cooling performance of your immersion chiller setup.

Wort Volume

Start Temperature

Target Temperature

Coolant Water Temperature

Water Flow Rate

Coil Length

Coil Tube Diameter (OD)

Outer diameter of copper tubing

How We Calculate This

Heat Transfer Calculation

Cooling time is estimated using: Time = Heat to Remove / (U x Surface Area x LMTD). U is the overall heat transfer coefficient (~800 W/m²·K for copper coils with moderate flow). LMTD is the log mean temperature difference between the wort and coolant water.

Coil Surface Area

The coil surface area determines how much heat can transfer per second. It is calculated from: Surface Area = π x Tube Diameter x Coil Length. Larger diameter tubing and longer coils increase performance.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.