The plate heat exchanger used in beer brewing is responsible for rapidly cooling the wort before fermentation begins. During operation, hot wort rich in proteins, hop residues, and other organic sediments flows through its channels. Even minor contamination remaining inside the device can lead to reduced cooling efficiency, but that's not the biggest problem – because if cleaning is neglected, wort heat exchangers can also increase the risk of beer infection and ruin the fruits of our labor.
Regular cleaning of the plate heat exchanger helps maintain high hygiene standards in the production process and extends the device's lifespan. Neglecting maintenance can result in hard-to-remove beerstone, protein deposits, or microbial growth. In this article, we will discuss the issue of cleaning plate heat exchangers, specifically for this application: in home brewing.
In practice, heat exchangers used in classic applications, such as central heating, are cleaned rarely.
In brewing, however, the plate heat exchanger should be rinsed after every use, meaning after each completed brew day. Even if brewing is done regularly, you should never leave wort residues inside the device until the next day. High temperature and humidity promote the growth of bacteria and wild yeast.
✅ Leaving wort residues for even 1 day until the next brew should be avoided if we care about maximum safety and preventing contamination of our batch.
More thorough chemical cleaning can optionally be done periodically, especially when:
In the case of intensive use in craft breweries, full cleaning is often performed after each brew. Even despite the need to clean beer heat exchangers, the heat exchanger used in brewing still saves the brewer time compared to traditional immersion chillers.
To clean beer heat exchangers, alkaline agents and disinfecting preparations intended for the food industry are mainly used. The most popular are:
Do not use aggressive chemicals of unknown origin or preparations that could damage stainless steel. It is also important to follow the manufacturer's recommendations regarding concentration and solution temperature. The best place to buy these types of agents is directly from homebrew supply stores.
If a situation arises where we have started a brew and realize too late that we don't have prepared cleaning agents for our plate wort heat exchanger, there is an alternative method. It should not be treated as a permanent alternative, but rather as a possible last resort. That alternative is citric acid.
Using citric acid to clean heat exchangers was discovered and popularized by heat exchanger users in campers. In caravanning, heat exchangers for hot water are often used, and naturally, they also need cleaning there. The advantage of citric acid is that it is easily available in various European countries. However, it must be handled with great care.
✅ Citric acid should only be used as a last resort and in low concentrations – otherwise, it can be harmful to the copper brazing of the heat exchanger. The acid should be diluted, preferably at a not-too-high concentration, and during the rinsing process, we should observe the color of the water flowing out of the heat exchanger. If it turns a strong blue hue, it means the concentration is high enough for the acid to react with the copper. This is not a good sign – the concentration is too high, and the acid should be further diluted. The rinsing water may only have a slightly bluish tint at most.
✅ Remember not to leave the citric acid solution in the heat exchanger for an extended period.
Rinsing the plate wort heat exchanger should be done immediately after cooling is finished – and, of course, after the proper sanitizing procedure using cleaning agents. Fresh protein deposits, hop residues, and sugars are much easier to remove than dirt that has dried inside the channels. The best practice is to flush the device with hot water in the opposite direction to the normal wort flow – so-called backflushing. This helps push contaminants out of the heat exchanger more effectively. In fact, you should change the direction of water flow several times during rinsing.
In the case of heavier soiling, it is worth using a recirculation flush with a pump and a PBW-type agent or an alkaline preparation intended for food-grade installations. After rinsing, the heat exchanger should be thoroughly rinsed with clean water. Regular rinsing significantly reduces the risk of beer infection and loss of cooling efficiency.
If a long time has passed since the previous brew – it is worth rinsing the chiller before brewing as well, to remove any potential dust.
Most brazed plate heat exchangers used for brewing are non-serviceable designs. This means that cleaning can only be done by flow-through methods. For this reason, regular rinsing immediately after use is particularly important.
While there are also gasketed heat exchangers that allow the plates to be taken apart and dirt removed manually, they are less common in home brewing due to their higher price and larger size. In fact, these are different types of heat exchangers, used for other applications.
The best way to reduce or prevent contamination is to filter the wort before it enters the heat exchanger. However, remember that this does not eliminate the need for cleaning. Helpful tools include:
The fewer hop particles and sediments that enter the heat exchanger channels, the easier its subsequent cleaning will be. It is also worth avoiding leaving the device with liquid residues inside.
A dirty plate heat exchanger can cause many technological problems. The most common symptoms are:
If the device continues to perform poorly despite cleaning, it may mean permanent scaling of the channels or the need to use a stronger cleaning agent.
A properly used and regularly cleaned plate heat exchanger can operate for many years without loss of performance. Key factors are quick rinsing after each brew and periodic chemical cleaning. Also helpful is careful finishing of the work – i.e., putting the heat exchanger away after cooling only when we are sure all the wort has drained. Do not leave the heat exchanger accumulating wort residues.
Maintaining heat exchanger hygiene is not only a matter of device durability but also the quality of the finished beer. Even the best recipe will not guarantee a good result if the cooling process takes place in a dirty system.
Check out wort heat exchangers for beer from the Nordic Tec brand:
Undersizing of a heat exchanger - what does it mean in practice?
Oversizing the heat exchanger - what is it for?
What is the production process of brazed plate heat exchangers?
How to choose a heat exchanger for a gas boiler?
How to properly connect a Nordic Tec plate heat exchanger? Can I reverse the flow directions?
History of plate heat exchangers
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