Why Decaf Extracts Differently

Espresso, Explained · Part 9

Decaf is not ordinary coffee with the caffeine removed. Taking the caffeine out puts the green bean through water and heat, which leaves it more porous, so the same settings give you a different shot.

01 The bean has already been through something

Removing caffeine means wetting the green bean and applying heat.

Whichever process is used, that much is common to all of them. What comes out the other side is a bean with a looser structure that breaks apart more easily.

It behaves differently in the roaster too.

Colour darkens early and the cracks sound faint. It is hard to judge by surface colour alone, which makes it demanding to roast well.

Caffeine is not gone entirely.

Most of it is removed, but a small amount remains. It is safer not to describe it to a customer as caffeine-free.

02 It grinds finer at the same setting

A bean that breaks easily produces smaller particles at the same dial position.

It also produces more fines. Water moves through more slowly, the shot runs long, and left alone the cup turns bitter and drying.

There is a tendency pulling the other way as well.

The looser structure also lets water soak in quickly. That is why you will find advice telling you to grind finer and advice telling you to grind coarser. Rather than deciding in advance, pull one shot and find out.

Thin crema is normal.

There is less gas in the bean, so less foam rises. Do not judge the shot by the crema alone.

03 Give it its own settings and its own equipment

Start from your regular dial position and move in one direction only.

Pull a shot, look at the time and taste it, then decide which way to go. Write the setting down separately so you are not searching for it again next week.

A second grinder is the reliable answer.

Switching one grinder back and forth mixes retained grounds every time you move the dial, and a customer avoiding caffeine can end up with regular coffee in the cup. With only one machine, grind a small amount through and discard it before you make the decaf drink.

Buy it in small bags, more often.

Decaf changes faster in storage and sells more slowly. Buy a large bag and the last of it is noticeably flat.

04 Read the symptoms differently

Judge it against regular coffee and you will fix the wrong thing.

These are the symptoms that come up most often with decaf.

What you see in the cup	Likely cause	What to do
Same setting, longer shot	Grinding finer than before	Move the grind coarser
Bitter and drying	Fines and over-extraction	Lower the yield and drop the water temperature slightly
Almost no crema	Less gas in the bean	Normal, so judge by taste instead
Flat within a few days	Changes quickly in storage	Switch to smaller bags and check the roast date

Decaf tasting bad is no longer a given.

Processing has improved enough that a well-roasted, well-pulled decaf is worth drinking. The problem is treating it exactly like regular coffee.

First Penguin Coffee Company We keep a decaf in the range and roast it to order like everything else. Ask us about settings when you order. 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

Next: the claim that a shot dies after 30 seconds.