When to Replace Grinder Burrs, and the Signs of Wear

Espresso, Explained · Part 12

Burrs are not a part that fails. They wear a little every day, and replacement is measured by the total weight of coffee they have ground rather than by how long you have owned them.

01 Dull burrs crush instead of cutting

Sharp burrs cut the bean.

Cut particles come out at a consistent size with fewer fines, water passes evenly, and the cup stays stable.

Worn burrs press and break instead.

Particle size scatters and fines increase. The same dial setting now gives you a different cup each time, sweetness drops, and astringency arrives earlier.

Still spinning is not the same as still working.

Burrs do not snap and stop. They wear down gradually, and nothing having broken is not the same as the part doing its job.

02 Count kilograms, not months

How many years you have had them tells you nothing.

A café grinding 2 kg a day and one grinding 20 kg a day do not share the same year. The measure is the total weight that has passed through.

Service life varies by model.

Burr diameter and material change the figure considerably, so check the manual for yours. The number a manufacturer publishes is the point at which the burrs are finished rather than the window in which they taste good, so start paying attention somewhere between half and three quarters of it.

In a café, add up what you order.

Note the weight of coffee you take in each month and accumulate it from the date of the last replacement. At home, counting bags is precise enough.

03 Wear arrives as several signs at once

Do not judge by any one of them alone.

When these turn up together, it is time to suspect the burrs.

What you notice	What it means	What to do first
The dial keeps moving finer	You have to close up more for the same grind	Check the weight ground since the last change
Louder and slower to grind	Crushing rather than cutting	Clean it first and check again
Grounds come out warm and clumped	More heat and more fines	Try grinding smaller amounts at a time
Less sweetness, early astringency	Particle size is uneven	If a different coffee behaves the same, look at the burrs

Clean before you conclude anything.

Oil and grounds packed between the burrs produce the same symptoms. If a brush and a proper grinder cleaner do not bring it back, then treat it as wear. Never wash burrs with water.

04 Replacing them properly

Change both at once.

Leave one old burr in place and the pair no longer meets correctly, so the grind stays uneven. Replace both even if only one looks worn.

New burrs need breaking in.

The surfaces are rough at first and the grind is inconsistent. Run some coffee through before you dial anything in, or the numbers will keep moving.

Reset the grind from scratch.

Your old setting will give you a completely different shot. Write down the date of the change and the weight accumulated up to that point, and the next replacement date works itself out.

First Penguin Coffee Company We roast to order and ship afterwards. For wholesale customers we visit on the first order and dial the grinder in with you. Our coffees are listed under Beans in the top menu. Enquiries: 010-3444-1721

Also in Korean This article is also published in Korean. The original series it draws on, 50 parts on café practice, runs on our Naver blog. Read the Korean series

That is the twelfth and final part of Espresso, Explained. The earlier articles are collected under the Home Barista label.