The Impact of Cleanliness on Coffee Flavor

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People spend a fortune every year getting professionals to scrub every internal surface of their ovens. It’s almost a requirement of a responsible homeowner. 

But when it comes to coffee machines, it’s a different story. Even aficionados are more casual about their hygiene standards than you might think. Many believe the equipment cleans itself. 

Of course, that’s not the case. Coffee machines attract grime and dirt just like any other food processing device. And that’s a problem if you’ve made it your mission to craft the perfect coffee every time, either at home or for your business. 

To be fair, how you clean a coffee machine isn’t always obvious. These complicated gadgets are full of pipes and chambers that are hard to reach. 

Even so, there are techniques you can use. Applying them ensures your coffee is perfect every time. 

The purpose of this post is to explain how cleanliness impacts coffee flavor. We look at how a clean coffee machine can make better coffee, its effects on flavor, and how you can clean your appliances. 

Why Do Clean Coffee Machines Make Better Coffees? 

Clean coffee machines make better coffee for several reasons.

First, dirty machines create problems when coffee oils build up and go rancid. Like kitchen pipes, the fats in roasted coffee build up on internal surfaces, changing the flavor of the resulting drink. 

If your coffee tastes more bitter than usual, rancidity in your machine is the likely culprit. When bean oils break down, they disturb the balance of flavors. Fats usually accommodate some of the bitterness naturally present in coffee. But when their chemical constitution changes, it amplifies the bitterness of other elements in the bean, making the drink sharper. 

Second, dirty machines can attract limescale in hardwater areas. As these deposits build up, they reduce the water flow and efficiency of the appliance, changing temperatures and extraction. 

Most machines can accommodate some limescale. But over time, it can prevent them from functioning. Too many deposits can trick internal thermostats into heating too much. Limescale can also interfere with extraction, preventing the coffees from containing the optimal balance of bean constituents. 

Naturally, cleaning your machine more often will help it last longer. Sanitary components will enable it to function for years to come. 

The Effects Of Cleanliness On The Taste Of Coffee

The effects of cleanliness on coffee’s taste can be significant. It can mean the difference between a drink you love and one you hate. 

Brighter, More Delicate Flavor

Cleaner machines give you a brighter and more delicate flavor. Removing rancid coffee oils prevents unpleasant, bitter, and stale tastes, letting you detect more of the nuance in the bean. 

For example, coffees made in clean machines are more likely to reflect the character of the beans in the hopper. Hygienic extraction promotes balance in phytonutrient composition. 

Coffee is also gentler on the palate. The roast of the beans is the primary determinant of the bitterness level, not residues in the machine. 

Superior Extraction

Clean coffee machines also permit better extraction. Limescale and oils can reduce water flow and prevent machines from drawing flavors from the beans during brewing. 

For example, consistent brewing action (where water passes through coffee grounds) makes every coffee taste the same when made with identical settings. The strength, color, and flavorful notes are similar. 

Optimal temperatures also prevent weak or sour coffee. Heating elements can bring water to the optimal range, allowing precise calibration of the drink. 

More Freshness

More freshness is another benefit of clean coffee machines.

Coffee beans can absorb chemicals in the surrounding environment, changing their taste. Therefore, cleaning maintains a neutral environment and protects them from reactive particles nearby that could change the drink’s character. 

Less Mold

Finally, keeping your coffee machine clean reduces the risk of mold and other microorganisms thriving that could affect taste. 

Which Types Of Coffee Machines Are Most Prone To Dirtiness? 

Coffee machines with the more complicated internal workings are the most prone to dirtiness. Therefore, you will need to pay more attention to these appliances.

For example, espresso machines have intricate group heads, steam wands, and brew heads. These components are prone to coffee grounds, milk, and mineral residue. 

Drip coffee makers are simple and more straightforward to clean, owing to the accessible (and often removable) carafe and filter basket. However, you must still check the water reservoir and heating element for limescale buildup. 

Machines that make milk-based drinks require extra cleaning. That’s because milk contains more fats and proteins that can accumulate on unseen, internal surfaces and turn putrid.

Finally, pour-over stands with permanent filters are also prone to dirtiness. Oils and grounds from beans can become stuck inside. As such, you’ll want to clean these filters after each use to prevent unwanted changes to your drinks’ taste. 

Knowing your machine’s unique cleaning requirements tells you when to clean it. The more you can take care of it, the more consistent your drinks’ flavor will be. 

5 Tell-tale Signs You Need To Clean Your Coffee Machine

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Off-flavors are one sign you need to clean your coffee machine, but there are others. Responding to these will help prevent sudden changes in drink quality. 

Slow Brewing

Slow brewing is often an indication your coffee machine needs cleaning. Clogged pipes, filters, and passageways slow the movement of liquid, reducing drink-making speed. 

Over time, this slowness can change how your coffee tastes. Incorrect brew times may increase bitterness or prevent water temperatures from rising to the correct level. 

Visible Residues

Visible residues are another sign your coffee machine requires cleaning. Grime can accumulate on the carafe, filter basket, and exterior pipework. 

This residue often stays stuck to your machine’s components. However, it can also flake off into your drinks, changing how they taste (and giving you the occasional lumpy and unpleasant surprise). 

Unusual Noises

The dirt inside your coffee machine can also lead to unusual noises that sound different from when you bought it. Excessive grime often leads to knocking and gurgling sounds as the machine tries to perform according to its specifications but can’t because of blockages or grime-induced inefficiencies. 

Reduced Water Flow

Reduced water flow is another sign you need to clean your coffee machine that occurs for a similar reason. Limescale and mineral deposits can build up inside the machine in hardwater areas, restricting water flow and preventing you from getting the tasty drinks you want. 

Lukewarm Coffee

Finally, warm or tepid coffee is another sign to clean your machine. When mineral deposits coat the heating element, they can prevent it from functioning optimally, preventing water from reaching the optimal 195°F to 205°F for extraction.

How To Clean Your Coffee Machine

Living with a dirty coffee machine with sub-par performance is no fun. Fortunately, cleaning these appliances is often straightforward and something you can do yourself. Here’s what you need to know. 

Cleaning A Traditional Espresso Machine

Keeping a traditional espresso machine in good working order requires adhering to a regular cleaning schedule.


Daily tasks after every use should include: 

  • Wiping down the machine’s exterior with a damp, clean cloth, paying attention to any parts that come into contact with fluids
  • Cleaning any milk or coffee splashes from the chassis
  • Cleaning the steam wand milk vent holes with the steam wand poker on the back of the Pallo Coffeetool bristle head
  • Wiping down the portafilter containing the spent coffee puck, paying close attention to the group head and shower screen. (Remove any remaining coffee grounds before reinserting into the machine). 
  • Brushing away loose coffee grounds from the group head and filter screen with the Pallo Coffeetool Grouphead Brush after every shot and while backflushing your espresso machine.
  • Steaming the frothing wand to purge any residual liquid inside the tube and remove milk residueBackflushing the group head according to the manufacturer’s instructions (if applicable)


Weekly cleaning should include: 

  • Scrubbing the portafilter basket and dispersion screen or submerging in a cleaning solution to remove more traces of coffee residue
  • Scrubbing the hard to reach areas on portafilter spouts with the Pallo Steamy Wanda twisted wire brushPerforming a more comprehensive exterior cleaning, perhaps removing side panels if you use the machine a lot for commercial purposes
  • Soaking the steam wand in a manufacturer-approved liquid cleaning solutionScrubbing inside the steam wand using Pallo Steamy Wanda twisted wire brush  (remove steam wand tip with the Pallo Caffeine Wrench) 


Descaling the machine’s interiors is a monthly cleaning task. Here, you remove the residue and mineral deposits that can build up in hardwater areas. 

Most coffee machine manufacturers will recommend a descaling solution you can use for their espresso machines. These flush through the machine in place of the regular water supply, stripping out the unwanted material and ensuring the machine continues functioning to specification. Hard water leads to more scale build up. JoeGlo backflush detergent contains a water softener to help prevent scale build up.

Decaling formulations contain weak lactic or citric acids. These are potent enough to dissolve limescale but not so corrosive that they might damage your machine. The acid disrupts the chemical bonds holding mineral crystals together, causing various ions to separate and break up the deposits. 

As the crystals break down, they form a solution with the cleaning fluid, making them more soluble in water. When you flush your coffee machine, the mineral ions flow out with the water and out of the machine. 

Monthly descaling is usually sufficient to keep even the most heavily used machines squeaky clean. However, complete deposit removal is less likely if you only flush your machine once annually. You might get some of the mineralization but not all of it in a single pass. 


Servicing coffee machines annually isn’t essential, but it can help if you own a professional or commercial machine. Qualified technicians often take apart appliances and replace worn or damaged components to keep them functioning optimally. 

For example, you might need to replace: 

  • Group head gaskets – rubbers reals that fit around the group head and portafilter. These can crack or become worn out over time. 
  • One-way valves – these control the way water flows through the machine during operation but can become fatigued with excessive use, leading to water leakages.
  • Steam wand tip – these can become chipped or fatigued (which is why many commercial machines feature replaceable heads).
  • Shower screen – this fine mesh, which helps to distribute filtered coffee evenly, can become damaged, leading to lumpy or bitty drinks.
  • Milk frother gasket – these seal the milk frother similar to how group head gaskets fit around the group head. Over time, this seal can wear out, causing milk to leak.

Cleaning An Automatic Coffee Machine

The process for cleaning an automatic coffee machine is similar. 

Daily, you should: 

  • Empty the drip tray and coffee grounds
  • Clean and rinse the brew unite
  • Wipe down the exterior

Weekly, you should: 

  • Disassemble and clean the milk frother (if you use it)
  • Refer to your appliance’s manual for detailed cleaning instructions

Monthly cleanings should involve descaling and neutralization rinses. 

How To Descale Your Machine

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How you descale your coffee machine depends on your make and model. However, most appliances require a similar process. 

Step 1: Prepare The Descaling Solution

The first step is to prepare the descaling solution according to the manufacturer’s instructions. Usually, it involves mixing acid with water and various cleaning agents (often proprietary). 

Step 2: Run The Cycle

The next step is to run the standard brewing cycle, using the cleaning solution instead of the usual water. Some machines have a cleaning setting that pushes extra water through the system at higher temperatures. 

The cleaning solution circulates throughout the machine’s interior, stripping away mineralization and limescale. This action works on all surfaces, including internal pipes, tanks, and heating elements that come into contact with water. 

Step 3: Dissolving

Once the cleaning solution has had time to work, the flushing process begins. Here, the machine evacuates the limescale and cleaning fluid solution, carrying them out through the group head and through to the drainage tray. 

Step 4: Rinse

The final step is to re-rinse the machine with pure (preferably distilled) water. Most coffee machine owners do this, even if their cleaning solution says they don’t have to. 

Now You Know How Coffee Machine Cleanliness Affects Flavor

Coffee machine cleanliness affects flavor through several channels. Therefore, maintain a regular cleaning schedule for your appliance, cleaning it daily, weekly, and monthly. 

Once your coffee machine is in proper working order, you should notice your coffee flavors improving substantially.