Oily Coffee Beans
Why They Damage Your Automatic Machine (and What to Use Instead)

Save Your Machine: Why Oily Beans Are a No-Go for Your Automatic Brewer

Coffee Hero Australians love their coffee, especially the convenience of super-automatic, bean-to-cup machines that deliver a rich long black or creamy flat white with a single button tap. But even the best machines from De’Longhi, Jura, or Philips have one silent killer that most people don’t even realise they’re using:

Oily Coffee Beans.

These shiny, slippery beans might smell bold and intense, but they are the number-one reason machines clog, jam, or break down long before their lifespan should end. If you want your automatic machine to last and your coffee to taste clean and fresh this guide is essential reading.

What Are Oily Coffee Beans? (And Why They Spell Trouble)

You’ll recognise oily beans instantly: shiny, glossy, wet-looking, and greasy to the touch. They almost shimmer under the light.

This happens when beans are roasted beyond the “second crack,” forcing internal oils to seep out to the surface. These beans are usually labelled:

• French Roast

• Italian Roast

• Dark Espresso

• “Strong” blends

While they may produce a smoky, intense cup, that surface oil is a nightmare for grinders, brew units, and sensors inside automatic machines.
National Coffee Association - Coffee Roasting Basics

3 Ways Oily Beans Destroy Automatic Machines

Super-automatic machines rely on gravity to move beans from the hopper into the grinder. Oily beans disrupt this entire process.

1. The Sticky Grinder Disaster

Your super-automatic machine depends on gravity and frictionless movement for beans to fall smoothly into the grinder. Oily beans disrupt this entire flow.

What happens:

• Clogged burrs: Grounds clump together and block the grinding chamber.

• Stuck hopper: Beans cling to the sides and stop dropping down.

• Sensor confusion: The machine thinks it’s empty even when full, because sticky beans don’t fall into the grinder.

This is one of the most common causes of “No Beans,” “Fill Hopper,” and “Grinding Error” messages.

Home-Barista (Machine Maintenance Insights) 

2. Brew Unit Suffocation

Inside your machine, the brew unit is crucial it compresses the coffee and forces hot water through it.

Oily residue:

• Coats the screens and filters

• Builds into thick, tar-like gunk

• Overworks the brew motor

• Becomes nearly impossible to remove once hardened

Even daily cleaning tablets can struggle to cut through months-old baked-on oils.

3. Rancid Taste That Ruins Every Cup

Coffee oils oxidise rapidly. Once old oil gets stuck in your grinder or brew path:

• It turns sour

• Produces a rotten aftertaste

• Affects EVERY new batch of coffee

This is why people often complain that their coffee machine’s “flavours changed” or that their coffee suddenly tastes burnt.

The Comparison: Good Beans vs. Bad Beans

Here is a quick cheat sheet to help you choose the right bag at the shops or your local roaster Coffee Hero.

💡 "But I Like Strong Coffee!"

A common myth is that you need dark, oily beans to get a "strong" coffee. This isn't true.

"Strength" usually refers to the caffeine kick or the intensity of flavour. You can achieve a fantastic, punchy coffee with a Medium-Dark roast that doesn't have surface oil.

Try asking your local roaster for:

• A chocolatey Medium Roast.

• A "clean" Espresso blend.

• Beans that are roasted just before the "second crack" (before the oil comes out).

Top Tip: If you absolutely love the taste of oily dark roasts, buy a cheap separate blade grinder and use a French Press or a plunger instead. Keep them away from your automatic machine!

Damage Control: What if I’ve Already Used Them?

If you have been using oily beans and your machine is struggling, don’t panic. Follow these steps to chuck a "U-ey" and get back on track:

1. Empty the Hopper: Vacuum out the remaining beans (don't use water!).

2. Clean the Burrs: Use "Grinder Cleaning Pellets" (like Supergrindz). These are food-safe tablets you run through the grinder to absorb the oils.

3. Wipe Down: Use a dry paper towel to wipe the inside of the bean hopper.

4. Manual Clean: If your machine has a removable brew group (like most De'Longhi or Philips machines), take it out and rinse it thoroughly with warm water.

5. Switch Beans: Immediately switch to a drier, non-oily bean. It might take 5-10 cups to flush the old taste out completely.

Your super-automatic machine is a clever piece of kit, but it can’t handle the grease. Stick to matte, dry beans to ensure your morning cuppa tastes fresh and your machine lasts for years.

✔️ Machine-Safe Beans

• Colombia Single Origin - Smooth, chocolatey, no surface oil.

• Brazil Coffee Beans - Naturally low acid and low oil.

• Espresso Blends - Designed for reliability in automatic machines.
  

✔️ Learn More

• The 2026 Ultimate Guide to Buying Coffee Beans in Australia

• How to Store Coffee Beans Properly

Protect your machine, upgrade your flavour, and enjoy a cleaner, smoother cup.
Shop Coffee Hero’s machine-safe beans today

You’ll taste the difference and so will your machine.

Frequently Asked Questions 

1. Why are oily coffee beans bad for automatic machines?

Oily beans leave residue that clogs grinders, coats sensors, and builds into sticky layers on the brew unit. This causes blockages, bitter flavours, and expensive breakdowns.

2. Are oily coffee beans stronger?

No. Strength comes from coffee-to-water ratio and caffeine content not from roast darkness. Medium roasts can taste bold and strong without producing oil.

3. How can I tell if coffee beans are too oily for my machine?

If the beans look shiny, glossy, or feel greasy, avoid them. Safe beans are matte, dry, and usually medium-roasted.

4. What roast level is best for super-automatic machines?

Medium roast (City or Full City) is ideal. It preserves flavour without forcing oils to the surface.

5. Can oily beans permanently damage my coffee machine?

Yes. Long-term use can burn out the grinder motor, clog the brew path, and cause sensor failures that require costly repairs.

6. What beans should I buy instead?

Choose matte, dry beans such as:

• Colombia Single Origin

• Brazil natural-process beans

• Medium espresso blends

7. How do I clean my machine after using oily beans?

Use grinder pellets, clean the hopper, flush the brew group, and run several cycles using dry medium-roast beans to clear out old oils.

8. Why do dark roasts look oily?

Dark roasts break the bean structure, pushing internal oils to the surface. This is a sign the bean has been roasted past the point suitable for automatic machines.

9. Does storing beans wrong make them oily?

No. Beans become oily from roasting not storage. However, storing beans in heat or sunlight can accelerate oil oxidation.

10. What is the best Coffee Hero product for automatic machines?

The best choice is Colombia Single Origin or one of Coffee Hero’s Espresso blends, which are crafted specifically for grinder stability and clean extraction.