Deciding to buy a wort chiller leaves you with some choices to make. Should you buy an immersion chiller, a counterflow chiller, or a plate chiller? If you decide to buy an immersion wort chiller you will need to choose between a copper chiller and a stainless steel model. Let’s take a look at the advantages and disadvantages of both.
Copper Immersion Wort Chillers
Copper has been the standard metal of wort chillers for a long time. Only in recent years, with the rise of the price of copper, did stainless steel chillers come on to the scene to compete with copper.
Advantages of Copper
- Copper has great thermal conductivity. It allows heat to travel efficiently through it from the hot wort into the colder water, which then carries the heat away.
- Copper is malleable so it can be shaped into the correct form for a wort chiller, even by the average home brewer. Great thermal conductivity allows the walls of copper tubing to be relatively thick so that they are easier to bend into shape without breaking but still can cool hot wort very quickly.
- Copper is known for its resistance to corrosion which is important when working with substances that will be consumed.
Disadvantages of Copper
- Price fluctuation is the greatest enemy of copper. Over the past five years the price per pound of copper has fluctuated between $1.50 and $4.50. When copper reaches the higher prices it opens up opportunities for products like stainless steel wort chillers to become economical.
- A minor disadvantage of copper is that it oxidizes. As copper is exposed to air it will turn a darker color, and then when it is used to cool wort it comes out of the wort looking shiny. This may look bad, but in reality the change in the copper’s appearance does not do any harm to the wort.
Stainless Steel Immersion Wort Chillers
Stainless steel chillers have become increasingly economical with the rise in price of copper. The benefits of stainless steel have even made these chillers the preference for some brewers.
Advantages of Stainless Steel
- Stainless steel is a compound metal that can be made in different grades and with some variability in the types of metal used in it. This flexibility means that the price of the stainless steel used to construct wort chillers can be controlled to a certain extent, while copper wort chillers are completely dependent upon the price of copper at a given time.
- Stainless steel is stronger than copper, so it is more difficult to damage. This strength also allows stainless steel tubing to be made with thinner walls, partially negating the advantage in thermal conductivity that copper holds.
- Stainless steel is easier to maintain. It does not oxidize, and it will not corrode.
Disadvantages of Stainless Steel
- Lower thermal conductivity makes stainless steel less efficient than copper
- Stainless steel is more difficult to work with. It is tough for home brewers to fabricate or their own wort chiller with stainless steel or to re-shape their wort chiller to fit into a new kettle if necessary.
Comparing Copper and Stainless Steel
- Efficiency: Comparisons of the cooling time between equivalent copper and stainless steel immersion chillers show that copper does have an edge in efficiency. This video from Homebrew Heaven gives a good example of the comparison.
- Cost: The cost of metals can change dramatically over months and years. Below are examples of 3/8″ immersion chillers in both 25 and 50 foot lengths, made of both copper and stainless steel. The prices listed are the up-to-date prices of the chillers on Amazon.com. Keep in mind, the price is also affected by the size of the tubing and the fittings that are included with the chiller.