Sugarcane Decaf: How the Ethyl Acetate Process Takes the Caffeine Out

Written by Tiny Tiger Coffee

Have you ever picked up a bag of decaf, seen "sugarcane process" on the label and wondered what sugarcane has to do with coffee? It sounds like a marketing line. It isn't, and the story behind it is one of the more surprising things in coffee.

What is ethyl acetate?

Sugarcane decaf uses a solvent called ethyl acetate. The name sounds serious, but it is a simple compound made from two things you already know: alcohol and the main acid in vinegar.

• It is found in fruit. Apples and pears contain it naturally.
• It comes from sugarcane. It is made as a by-product when sugarcane molasses is fermented, which is where the "sugarcane" name comes from.
• It is choosy. It picks up caffeine and leaves most of a bean's other flavours behind.

Inside the world's largest decaf plant

In Bremen, in northern Germany, sits the largest decaffeination plant in the world. It is less a factory than a campus, with buildings joined by metal tubes that blow coffee from one to the next with compressed air. It runs 24 hours a day, every day of the year, and decaffeinates over 120,000 tonnes of coffee a year. That is more than 20 shipping containers every day.

Here is what happens to a batch of green coffee there:

1. Cleaning. The coffee is unloaded and cleaned of dust and anything else that came with it from the farm.
2. Steaming. The thin silver skin is removed and the beans are steamed. Steam opens the bean up so the caffeine can get out.
3. Washing out the caffeine. The beans go into one of 12 steel tanks, each six metres tall and holding about four tonnes. Ethyl acetate is added and the beans are churned at around 70°C for about eight hours. The solvent is drained and replaced 6 to 10 times, depending on how much caffeine the coffee started with.
4. Steaming the solvent off. Ethyl acetate boils at about 77°C, well below water. So steam is pumped through the tanks, first for 90 minutes at 100°C and then for 60 minutes at 105°C, and the solvent boils away.
5. Drying. The beans are dried for about two hours, back to 10 to 12% moisture, the same as ordinary green coffee.
6. Checking. A lab grinds a sample, measures the caffeine left with a precise lab test, and a tasting team cups 80 to 100 samples a day before anything is cleared.

What happens to the caffeine?

Nothing is wasted. The caffeine is moved into water, cleaned with activated carbon, filtered and crystallised. The first crystals are a greyish brown powder. After four rounds of cleaning they are bright white, and the caffeine is sold, since it has a value of its own. One tonne of it is enough for about 33 million cans of cola.

Is sugarcane decaf safe, and does it taste good?

It is safe. The solvent is steamed off before the coffee leaves the tank, and the coffee is tested afterwards. Because ethyl acetate is so selective, good sugarcane decafs can taste sweet and clean.

We chose a different route for our own Decaffeinated Toasted Almond: it is decaffeinated with CO2, which uses no solvent at all. We compare all the methods in our guide to what decaf coffee is.

Common questions

Is sugarcane decaf chemical-free?

No. It uses a solvent, ethyl acetate, but one that occurs naturally in fruit and is removed with steam before the coffee is roasted.

Is sugarcane decaf better than CO2 decaf?

Both keep flavour well. The quality of the bean and the roast matter more than the method.