Immersion vs. Counterflow Wort Chillers: Which is Best?

Learn the differences between immersion and counterflow wort chillers, along with which is best at certain tasks

BREWING EQUIPMENT

Mat Stuckey

9/21/20239 min read

For homebrewers looking to upgrade from small batch brewing with ice baths, both immersion and counterflow wort chillers offer more efficient cooling. But which one is right for your home brewery?

Immersion Chiller Overview

An immersion chiller consists of a coil of copper or stainless steel tubing that is placed directly into the hot wort. Cold water runs through the tubing, cooling the wort through direct contact.

Advantages of Immersion Chillers:

  • Low Cost - Immersion chillers are one of the most affordable wort chilling options. A 25' copper immersion chiller can be purchased for under £50.

  • Simple Design - No pump is required since the chiller sits directly in the wort. Easy to use and maintain.

  • Compact Size - Coils up for convenient storage. Great for small home breweries.

  • Easy Sanitation - Only the outer surface of the tubing contacts the wort, so cleaning is straightforward.

Disadvantages of Immersion Chillers:

  • Slower Cooling - Only the wort touching the coils gets chilled directly. Larger batches take longer to cool.

  • Inconsistent Cooling - Wort should be stirred constantly to ensure even temperature distribution.

  • Size Limitations - Longer coils are needed for bigger batches. A 50' chiller is better for 5 gallons or more.

  • Pre-Chilling Required - The cold groundwater may need pre-chilling for maximum efficiency.

How Immersion Chillers Work

An immersion chiller is placed into the hot wort immediately after the boil is finished. Cold water enters one end of the coiled tubing and exits the other end, absorbing heat from the wort through the tubing walls.

Constant stirring is crucial to bring hot wort into contact with the chilled metal coils. As fresh hot wort circulates next to the coils, it is quickly cooled down. The cold break material formed during chilling helps clarify the finished beer.

For optimal efficiency, the immersion chiller's input water should be pre-chilled before entering the coils. This can be done using ice water in a pre-chiller bucket or using a wort chiller pre-chiller accessory. The colder the input water, the faster the wort will chill.

Immersion Chiller Size and Shape

For a 5 gallon batch size, a 25 foot long, 3/8" diameter immersion chiller is sufficient. The 3/8" tubing allows a good balance of heat transfer versus water flow rate.

Larger batches above 5 gallons benefit from a 50 foot long, 1/2" diameter immersion chiller. The increased length and diameter provides more cooling power.

Coils should have tight bends no greater than 1.5" diameter. Tighter bends increase turbulence and improve heat transfer. Straight pipe sections should be minimised.

Square coils provide more surface area contact versus round coils of the same length. However, round coils can be more easily stirred and stored.

Immersion Chiller Tubing Material

Copper is the most efficient material for immersion chillers thanks to its high thermal conductivity. It quickly transfers heat from the hot wort through the tubing wall.

Stainless steel is also common but less thermally conductive, resulting in slower chilling. However, it resists corrosion and is easy to clean.

Chillers made with 3/8" type M rigid copper tubing offer the best performance for the price.

Setting Up an Immersion Chiller

To use an immersion chiller:

  1. Sterilise the chiller by soaking it in sanitising solution prior to brew day. Rinse thoroughly before use.

  2. Boil wort as normal. Turn off heat when boil is complete.

  3. Connect plastic tubing to the immersion chiller and attach a hose or sink faucet adapter.

  4. Lower the immersion chiller into the brew kettle. Turn on the water supply.

  5. Constantly stir the wort using a sanitised spoon or paddle. Keep stirring!

  6. Monitor the wort temperature using a thermometer. When it nears pitching temp, stop water flow and remove chiller.

  7. Pitch yeast once wort reaches desired temperature.

  8. After use, rinse the chiller thoroughly before storing. Periodically sanitise with PBW and acid.

With practice, an immersion chiller can quickly cool 5 gallons of boiling wort to yeast pitching temperature within 15-20 minutes.

Counterflow Chiller Overview

A counterflow chiller consists of a tube inside a tube. Hot wort flows through the inner tube, while cold water flows countercurrent in the outer tube.

Advantages of Counterflow Chillers:

  • Fast Cooling - Can chill 5+ gallons in a single pass. Higher throughput than immersion chillers.

  • Consistent Cooling - Entire volume of wort chilled uniformly. No need to stir.

  • Compact Design - Efficient heat transfer in a small package. Great for tight home breweries.

  • No Direct Contact - Wort only touches internal tubing, minimising contamination risks.

Disadvantages of Counterflow Chillers:

  • Higher Cost - More expensive than immersion options due to intricate design.

  • Pump Required - Wort must be pumped through for proper flow. Adds complexity.

  • Difficult Cleaning - Cannot scrub inside walls of inner tube. Requires special brushes.

  • Size Limitations - Very long chillers needed for big batches. Can clog if too small.

How Counterflow Chillers Work

In a counterflow chiller, hot wort enters one end of the inner tube while cold water enters the outer tube in the opposite direction.

As the liquids pass countercurrent, heat is efficiently transferred through the tubing walls. The wort exits chilled to pitching temperature in a single pass.

Since the entire volume of wort passes through the inner tube, uniform chilling is ensured. No stirring is required.

For maximum efficiency, the wort should enter around 170°F. A pump is used to ensure smooth wort flow through the inner tube. Matching the flow rate between the wort and cold water is also critical.

Counterflow Chiller Size and Shape

Counterflow chillers use the same 3/8" or 1/2" copper tubing as immersion chillers. The key factors are the length of tubing and the shape of the coils.

For 5 gallon batches, 20' of tubing is sufficient. Larger batches require 25' of tubing or more.

The tubes should be coiled as tightly as possible to maximise surface area for heat transfer. Tight bends are crucial for performance.

Twice as much surface area is needed compared to an immersion chiller due to the lower temperature differential. More overall tubing length is required.

Counterflow Chiller Tubing Material

As with immersion chillers, copper offers the best thermal conductivity and chilling performance.

Stainless steel can also be used but with reduced efficiency. It is easier to clean and more corrosion resistant.

Using a high quality 1/2" type M rigid copper pipe will provide the best results.

Setting Up a Counterflow Chiller

Proper use of a counterflow chiller requires a pump and chilled water supply:

  1. Disassemble and thoroughly clean/sanitise all parts before each use. Reassemble when ready to chill wort.

  2. Connect plastic tubing to the wort inlet/outlet and water inlet/outlet.

  3. Attach pump outlet to wort inlet. Have a chilled water supply ready.

  4. After the boil finishes, begin pumping hot wort into the chiller's inner tube. Simultaneously run cold water countercurrent.

  5. Monitor wort output temperature with a thermometer. Adjust flow rates as needed to optimise chilling.

  6. Collect chilled wort directly into the fermenter. Stop water flow and pump when done.

  7. Rinse then take apart the chiller again. Fully clean and sanitise all parts after each use.

When set up correctly, counterflow chillers can chill 5+ gallons of wort from boiling to under 70°F in just 10-15 minutes.

Copper vs. Stainless Steel Chillers

Both immersion and counterflow chillers are available in either copper or stainless steel:

  • Copper offers the best heat transfer thanks to its excellent thermal conductivity. This makes it the preferred material for efficiency.

  • Stainless steel has lower conductivity, so it is less efficient at chilling wort. But it has advantages like corrosion resistance, durability, and easier cleaning.

Other factors to consider when choosing between copper and stainless steel:

  • Cost - Copper is generally more expensive than stainless steel.

  • Maintenance - Stainless requires less effort to keep clean and sanitary. Copper can oxidise over time.

  • Compatibility - Stainless steel is fine for all beer styles. Some think copper can react with lighter beers.

  • Aesthetics - Many prefer the traditional look of a shiny copper chiller. Stainless has a more industrial appearance.

So in summary, experienced homebrewers tend to prefer the performance advantage of copper chillers. But stainless steel offers benefits like lower maintenance and cost.

Immersion vs. Counterflow Chiller Comparison

Deciding between an immersion chiller and counterflow chiller depends on your budget, batch size, and brewing system constraints:

Cost

  • Immersion chillers are more affordable, starting under £50.

  • Counterflow chillers are a bigger investment, starting around £90.

Cooling Power

  • Counterflow is more efficient, and can chill 5+ gallons in one pass.

  • Immersion requires stirring and may need multiple passes for larger batches.

Batch Size Suitability

  • Immersion is great for 5 gallon batches but may struggle with 10+ gallon batches.

  • Counterflow easily handles 5-10 gallon batches. Can be scaled up as you expand.

Brewing System Complexity

  • Immersion just needs a cold water source. No pump required.

  • Counterflow needs a pump and proper tubing setup. More involved.

Ease of Cleaning

  • Only the outer surface of an immersion chiller touches the wort. Very easy to clean.

  • Counterflow has internal tubes that are harder to scrub and sanitise.

Risk of Infection

  • Immersion chillers limit contact between wort and equipment.

  • More potential infection points with counterflow's tubes and connectors.

There is no universally "best" option. The right chiller depends on your unique needs and preferences as a homebrewer.

If optimising cost and simplicity, an immersion chiller is a great starting point. But if seeking faster chilling for larger batches, a counterflow chiller is likely the better investment.

Carefully consider your current and future cooling needs, budget, and brewing system capabilities when deciding on your upgrade. Either immersion or counterflow will be a major improvement over ice baths!

Choosing the Right Immersion Chiller Size

When purchasing an immersion chiller, longer is better. The increased length provides more cooling power:

  • 25 ft immersion chiller - Good for 5 gallon batches. Can work for 10 gallons with stirring.

  • 50 ft immersion chiller - Recommended for 10+ gallon batches. Provides faster chilling.

  • 75-100 ft immersion chillers - Only needed for very large 20+ gallon batches. Overkill for most homebrewing.

For chilling 5 gallon batches, a 25 foot chiller is usually sufficient. But consider investing in a 50 footer instead for faster chilling and the flexibility to upgrade to larger batches.

The diameter of the tubing also affects efficiency:

  • 3/8" diameter tubing - Best balance of heat transfer and water flow rate. The standard size.

  • 1/2" diameter tubing - Increased flow improves chilling but requires higher water pressure.

  • 5/8" diameter tubing - Only recommended for very long 100'+ chillers for massive batches.

Stick with 3/8" or 1/2" diameter tubing for a homebrew sized immersion chiller. And maximise the length based on your typical batch size.

Also look for tight 1-1.5” coils and minimal straight sections for optimal performance.

Choosing the Right Counterflow Chiller Size

For a counterflow chiller, longer is also better. But surface area is even more critical due to the heat transfer inefficiencies:

  • 10-15 ft counterflow - Too short for any batch size. Look for at least 20 ft.

  • 20 ft counterflow - Good surface area for 5 gallon batches.

  • 25 ft counterflow - Recommended minimum for 10 gallon batches.

  • 30+ ft counterflow - Better for larger 10-15 gallon batch sizes.

Ideally choose a chiller long enough to chill your target batch volume in one pass. Lengths under 20 ft often produce underwhelming results.

As with immersion chillers, 1/2" diameter tubing can improve flow rate and cooling power. But it requires higher water pressure.

Focus on maximising the tightly coiled surface area based on your batch size. Extra length is rarely wasted with a counterflow chiller design.

Using a Pre-Chiller with Immersion & Counterflow Chillers

To maximise efficiency for both immersion and counterflow chillers, use a wort chiller pre-chiller:

  • Lowers ground water temperature before entering chiller

  • Improves heat transfer and significantly speeds chilling

  • Allows achieving pitching temps for larger batches

Bucket Pre-Chiller

Fill a 5-gallon bucket with sanitiser solution and water + ice. Run water through the chiller coil in the bucket first.

Inline Pre-Chiller

Use a compact heat exchanger inline between the faucet and chiller inlet. Provides 20-30°F pre-cooling.

Recirculating Pre-Chiller

Pump ice water through the chiller and back to the bucket until it reaches the desired temp before using.

With proper pre-chilling, both immersion and counterflow chillers can achieve pitching temperature rapidly even on large batches.

Cleaning and Sterilising Chillers

Proper cleaning/sanitation of chillers prevents contamination and off-flavours:

Immersion Chiller Cleaning

  • PBW soak followed by sanitiser soak between brews

  • Scrub exterior coil surfaces with a brush

  • Flush tubing interior with sanitiser

  • Rinse thoroughly before next use

Counterflow Chiller Cleaning

  • Disassemble completely between uses

  • Soak all parts in PBW then sanitiser

  • Use bottle brush on interior tubing

  • Carefully scrub threads and connectors

  • Reassemble and test prior to chilling wort

Storage

  • Completely dry chillers after use

  • Coil up neatly to minimise kinks

  • Store in dry, dust-free area between uses

Regular cleaning and sanitation practices will maximise your chiller’s lifespan and effectiveness. Always inspect closely prior to each use.

Upgrading Efficiency with Chiller Pumps & pre-Chillers

Beyond the chiller itself, accessories like pumps and pre-chillers can boost performance:

  • Chiller Pumps - Needed for counterflow chillers. Also improves immersion chilling by recirculating wort. Look for high flow rate magnetic drive pumps.

  • Pre-Chiller - Lowers inlet water temp. Can add ice water or use inline heat exchanger. Drops water temp by 20°F or more.

  • Whirlpool Attachment - Directs wort flow in circular pattern around immersion chiller. Improves contact and heat transfer.

  • Thermometers - Monitor wort temperature entering and exiting chiller. Adjust flow rates to optimise ΔT.

  • Tubing & Hoses - Use opaque tubing to prevent light exposure. Silicone tubing avoids plastic flavours but kinks easily.

Don't overlook chiller accessories when designing your brewery. A powerful pump and pre-chiller can make a basic immersion chiller rival a counterflow system.

Wrapping Up

With the information above, you should now be equipped to choose the best wort chilling solution for your home brewery.

The humble immersion chiller remains a top choice for homebrewers focused on simplicity and affordability. Just be sure to get enough length for your batch size.

For more advanced brewers seeking speed and consistency, invest in a properly sized counterflow chiller. But factor in the added complexity and cost.

Whichever design you choose, dialling in the details like tubing length, pump flow rates, pre-chilling, and sanitation practices is key to getting maximum efficiency.

If you want more homebrewing tips, head over to the Brewpedia blog for loads more!