Why Is Coffee Machine Making A Hissing Noise?

If you’re an avid coffee lover like me, there’s nothing more frustrating than a coffee machine that’s making strange noises.

One common issue many coffee enthusiasts face is a hissing noise from their beloved coffee maker. But what exactly causes this unsettling sound?

A surge of steam that emerges from the anti-vacuum valve is what causes this. When the valve seals, the sound stops.

After the initial period of heating up, if you hear this hissing sound, the anti-vacuum valve might not be sealing properly.

On new machines, this occasionally occurs because the seal occasionally requires a little assistance to bed in.

The Anatomy of a Coffee Machine

Before we delve into the reasons for a hissing coffee machine, let’s briefly understand how these marvelous contraptions work.

Coffee machines, whether it’s drip coffee makers, espresso machines, or French presses, all have certain components in common.

The Anatomy of a Coffee Machine
Source: Sliding Motion

These include a water reservoir, heating element, pump, boiler, and various valves. The interaction of these components is responsible for brewing that perfect cup of joe.

Also Read: Why Breville Dual Boiler Fails To Reach The Temperature?

Why is the Coffee Machine Making a Hissing Noise?

Your espresso maker’s valve may be jammed open, allowing steam to escape. Your espresso maker may be making loud noises due to this.

To prevent strange noises, inspect the valve for damage and replace it right away. Before replacing a replacement part, make sure to unplug the espresso machine from the power supply.

1. Air in the Water Line

One possible reason for a hissing noise in your coffee machine is air trapped in the water line. This can occur when you haven’t used the machine for a while or after cleaning the unit. The trapped air can cause a hissing sound as it escapes through the system. To fix this issue, you can try the following steps:

  • Fill the water reservoir completely.
  • Run the coffee maker without coffee grounds, allowing it to go through a full brew cycle.
  • Repeat this process a couple of times to ensure all the air is purged from the system.

2. Faulty Pressure Relief Valve

Another culprit behind the hissing noise could be a faulty pressure relief valve. This valve is designed to regulate the pressure inside the coffee machine, preventing it from reaching dangerous levels.

If the valve malfunctions, it may release steam or air, resulting in a hissing sound. To troubleshoot this issue:

  • Consult the user manual or manufacturer’s website to locate the pressure relief valve.
  • Check if the valve is clean and not clogged with debris.
  • If the valve is damaged or worn out, contact the manufacturer for a replacement.

Also Read: Why Does My Coffee Machine Smell Like Cheap Perfume?

3. Scale Build-up in the Boiler

Scale, a mineral deposit that accumulates over time, can wreak havoc on your coffee machine.

If the hissing noise is accompanied by reduced water flow or slower brewing times, scale build-up in the boiler might be the cause. To tackle this issue:

  • Refer to the user manual to learn how to descale your specific coffee machine model.
  • Purchase a descaling solution or make a DIY solution using vinegar and water.
  • Follow the instructions carefully to descale the machine and remove any scale deposits.
Why is Coffee Machine Making a Hissing Noise?

4. Overheating Heating Element

Coffee machines rely on a heating element to warm the water to the ideal brewing temperature. However, if the heating element overheats, it can cause the water to boil excessively and create a hissing sound. Here’s what you can do:

  • Ensure the water level in the reservoir is within the recommended range.
  • Clean the heating element if it’s covered in mineral deposits.
  • If the problem persists, contact the manufacturer or a professional technician for assistance.

Also Read: Flushing Not Getting Rid Of Chemical Taste After Descaling?

What could be causing my coffee machine to make a hissing noise?

There are several possible causes for a coffee machine to make a hissing noise. Here are a few potential reasons:

  1. Steam Pressure: Hissing sounds in a coffee machine are often associated with the release of steam. If the hissing occurs during the brewing process, it could indicate that the machine is building up excessive pressure and releasing it through a valve or steam wand.
  2. Faulty Valve: A malfunctioning valve, such as the steam release valve or the pressure relief valve, can cause a hissing noise. If the valve is not sealing properly, steam or air may escape, resulting in a hissing sound.
  3. Clogged or Blocked Parts: A clog or blockage in the coffee machine’s internal components, such as the steam wand, pipes, or filters, can disrupt the flow of steam and lead to a hissing noise.
  4. Water Leak: In some cases, a hissing sound may be associated with a water leak within the coffee machine. If water is escaping from a damaged or loose connection, it could create a hissing noise as it comes into contact with hot components.
  5. Mineral Build-up: Over time, mineral deposits from hard water can accumulate in the coffee machine’s internal parts, causing blockages or affecting the performance of valves. This can lead to steam leakage and hissing sounds.
  6. Temperature Regulation: Some coffee machines use heating elements to maintain the water temperature. If the heating element is malfunctioning or struggling to regulate the temperature, it may result in hissing noises.

Also Read: Sage Coffee Machine Trips Fuse

Is it normal for a coffee machine to make a hissing sound?

In general, some coffee machines may produce a slight hissing sound during certain stages of operation, particularly when steam is being generated or released. This is often considered normal and is a result of the machine’s design and functionality.

Is it normal for a coffee machine to make a hissing sound?
Source: Coffee Machine Emporium AU

For example, espresso machines commonly use steam to froth milk or extract coffee, and the release of steam through the steam wand may produce a hissing sound.

Also Read: How Does Oscar’s HX Differ From Typical E61 HX?

Can a coffee machine hiss if it’s not properly maintained?

Yes, a coffee machine that is not properly maintained can potentially develop issues that lead to hissing sounds.

Regular maintenance is crucial to ensure the optimal performance and longevity of a coffee machine. Here are a few maintenance-related factors that could cause a coffee machine to hiss:

  1. Accumulated Mineral Deposits
  2. Loose or Damaged Connections
  3. Wear and Tear on Seals or Gaskets 
  4. Improper Cleaning

Also Read: Would It Be Possible To Power A Nespresso Machine?

Are there any safety concerns associated with a hissing noise coming from a coffee machine?

If the hissing is caused by excessive steam pressure or a malfunctioning valve, there is a risk of steam burns if it comes into contact with the skin. Additionally, water leakage accompanied by the hissing sound can lead to electrical hazards or slippery surfaces.

It is important to exercise caution, avoid placing hands or bodies near steam release areas, and address any issues promptly to ensure the safe operation of the coffee machine.

Also Read: Why Won’t My 1000W Inverter Run My 800W Coffee Maker?

Does the type of coffee machine affect the likelihood of it making a hissing noise?

Yes, the type of coffee machine can affect the likelihood of it making a hissing noise. Different types of coffee machines have varying mechanisms and functionalities, which can contribute to the production of hissing sounds. Here are a few examples:

Does the type of coffee machine affect the likelihood of it making a hissing noise?
Source: Roasty Coffee
  1. Espresso Machines: Espresso machines, especially those with steam wands, are more likely to produce hissing sounds. These machines use steam to froth milk and extract espresso, and the release of steam through the steam wand can create a hissing noise.
  2. Drip Coffee Machines: Drip coffee machines, which rely on gravity to brew coffee, typically have fewer components that generate hissing sounds. While they may produce some operational noises, such as the sounds of water dripping or the brewing process, hissing sounds are less common in this type of machine.
  3. Pod/Capsule Machines: Pod or capsule-based coffee machines often have fewer opportunities for hissing sounds because the water and coffee extraction processes are enclosed within the sealed capsules. However, certain models with additional features like steam wands for milk frothing may still produce hissing sounds during operation.
  4. Manual Brewing Methods: Manual brewing methods, such as the French press or pour-over, generally do not involve mechanisms that generate hissing noises. These methods rely on manual control of water flow, eliminating the need for steam or pressure-related components.

Also Read: Can I Use A European Espresso Machine In The US? 

Are there any specific components or parts that could be causing the hissing noise in a coffee machine?

Yes, there are specific components or parts in a coffee machine that could be causing the hissing noise. Here are some common culprits:

  1. Steam Wand
  2. Pressure Release Valve
  3. Water Lines and Connections
  4. Seals and Gaskets
  5. Pressure Relief Valve
  6. Solenoid Valve

Also Read: La Cimbali M24 DT3 Convert To Single-Phase

Are there any DIY solutions to resolve a hissing noise in a coffee machine, or should I contact a professional for help?

Are there any DIY solutions to resolve a hissing noise in a coffee machine, or should I contact a professional for help?
Source: CNET
  • Clean and descale the coffee machine to remove any mineral deposits or clogs.
  • Check and tighten all connections and fittings.
  • Consider replacing worn-out or damaged seals or gaskets.
  • Follow the user manual or contact the manufacturer for specific instructions.
  • If unsure or uncomfortable with DIY repairs, it’s advisable to contact a professional for assistance.

Also Read: Espresso Machine Voltage Converter From 110V To 240V


A hissing noise coming from your coffee machine can be unsettling, but it’s usually a solvable problem.

By identifying the root cause, whether it’s trapped air, a faulty valve, scale build-up, or an overheating heating element, you can take the necessary steps to fix the issue.

Remember to consult the user manual and follow the manufacturer’s instructions for your specific coffee machine model.

With proper maintenance and occasional troubleshooting, you’ll soon have your coffee machine brewing silently and producing that delightful cup of joe you crave.

Click And Collect More information: Coffee Machine.


Why does my coffee machine hiss when I turn it on?

When you turn on your coffee machine, a hissing noise can be attributed to the initial heating process.

As the heating element warms up, it may produce steam, which can escape through the valves and create a hissing sound. This is usually normal and nothing to worry about.

Why is my espresso machine whistling?

Gas, not liquid, produces whistling sounds, which are considerably more likely to come from the boiler than from the group of an espresso machine. Remove the case, then look for any little steam leaks.

Is a hissing coffee machine dangerous?

In most cases, a hissing coffee machine is not dangerous. It’s often a sign of minor issues that can be resolved with simple troubleshooting steps.

However, if you notice any unusual smells, smoke, or sparks, it’s crucial to turn off the machine and seek professional assistance immediately.

My coffee machine hisses and produces weak coffee. What should I do?

If your coffee machine is hissing and producing weak coffee, it could indicate a clog or blockage in the system.

Try cleaning the machine thoroughly, including the water reservoir, filter, and brewing components. If the problem persists, consider descaling the machine to remove any mineral deposits.

Can a hissing coffee machine be fixed at home?

Many hissing coffee machine issues can be fixed at home with basic troubleshooting. However, if you’re unsure or uncomfortable with DIY repairs, it’s always best to consult the user manual or contact the manufacturer’s customer support for guidance.

Should I continue using my coffee machine if it’s hissing?

It’s generally safe to continue using your coffee machine if it’s hissing but not exhibiting any other signs of malfunction.

However, it’s advisable to monitor the situation closely and perform any necessary maintenance or repairs to prevent further issues.

How often should I clean and descale my coffee machine?

The frequency of cleaning and descaling depends on various factors, including water hardness, usage frequency, and manufacturer recommendations.

As a general guideline, it’s recommended to clean your coffee machine thoroughly every one to three months and descale it every three to six months.

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