What Causes Espresso Machine Explosions? Why Do Portafilters Blow Out During Extraction?

Understanding Coffee Machine Handle Explosions

With the advent of affordable and compact home coffee machines, more and more people have equipped their homes with coffee machines to enjoy fresh, ground-to-order espresso anytime. However, what's growing alongside the number of coffee machines is a series of operational issues.

Recently, FrontStreet Coffee has noticed that many people online, due to improper operation, have experienced their portafilter being ejected from the coffee machine during coffee extraction (or after extraction), creating a messy situation like the one shown below.

The occurrence of this phenomenon not only easily damages the coffee machine but may also injure the operator. Even without physical injury, the mess of coffee stains can be quite demoralizing. Therefore, FrontStreet Coffee is here today to share why coffee machine handle explosions occur.

Why Do Coffee Machines Explode Their Handles?

Generally, this phenomenon is caused almost entirely by improper pressure release. The common scenarios where this occurs include: when removing the handle, during espresso extraction, and when cleaning the coffee machine.

When Removing the Handle

Explosions when removing the portafilter are common issues with many home machines. Most home coffee machines under a thousand yuan don't have comprehensive pressure release functions! This causes pressure to remain trapped immediately after extraction is complete.

If we hastily remove the portafilter at this moment, it can easily be ejected by the residual pressure. Therefore, to address this situation, we can适当 delay removing the portafilter, allowing pressure to dissipate properly before disassembly. This can reduce the risk of handle explosions.

During Espresso Extraction

It's not uncommon for handle explosions to occur during espresso extraction. This happens when pressure builds up over time, exceeding the pressure tolerance of the portafilter. There are two main reasons for pressure buildup: one is coffee ground too fine, and the other is filling the portafilter with more coffee than recommended.

When coffee is ground too fine, the coffee particles become more compact, significantly reducing the gaps for water flow. When the grind becomes fine enough, the coffee puck becomes very solid, making it difficult for water to pass through. Pressure then continues to build in the confined space. Similarly, when we tamp more coffee than the recommended amount, the gaps in the coffee puck become narrower. Hot water and pressure struggle to pass through, and with nowhere to release, pressure accumulates repeatedly, leading to the risk of handle explosions.

Therefore, if we notice that no liquid emerges from the bottom of the portafilter for an extended time during extraction, and the pressure gauge remains at peak levels, these two factors are likely the cause. In such cases, it's best to stop extraction, readjust the coffee amount or grind size, and reduce the occurrence of handle explosions.

Additionally, there's another reason: "not securing the handle properly." Many people have learned this lesson the hard way – by not applying enough force when locking the portafilter, causing it to be ejected during the extraction process!

While this phenomenon might not cause as much damage compared to others, it's still very dangerous. Therefore, when securing the portafilter, we must ensure it's locked tightly.

When Cleaning the Coffee Machine

Finally, let's discuss cleaning! When we clean our coffee machines, we replace the regular portafilter basket with a blind basket (one without holes), allowing cleaning agents inside to be drawn back through the machine's pressure release system for effective cleaning. However, many people mistakenly believe that leaving the coffee machine running continuously will clean it properly – this is incorrect!

As mentioned earlier, if pressure isn't released during the coffee machine's operation, it will continue to build up. When it exceeds the pressure tolerance of the portafilter, it creates the risk of explosions. Therefore, FrontStreet Coffee suggests periodically releasing pressure when cleaning the portafilter. This not only ensures effective cleaning but also avoids the risk of machine explosions. The specific procedure is: pour coffee machine cleaning powder into a blind basket, secure the portafilter to the portafilter holder, open the water valve for 10 seconds, then close it. Repeat this process three times.

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Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473