Water process decaf is coffee that has had its caffeine removed using only water, time, temperature and filtration. No chemical solvents touch the beans. It is the method we use for our Mexican water process decaf.
How water process decaffeination works
- Soaking. Green coffee is soaked in hot water. Caffeine dissolves, along with many of the compounds that give coffee its flavour.
- Filtering. The water passes through activated carbon filters that trap caffeine molecules while letting the flavour compounds through.
- Flavour-saturated water. This caffeine-free, flavour-rich water is used to soak the next batch of beans. Because the water is already saturated with flavour compounds, mostly caffeine leaves the beans.
- Drying. The decaffeinated beans are dried back to normal green coffee moisture and shipped for roasting.
Water process methods typically remove around 99.9% of the caffeine.
How it compares with other methods
| Method | What removes caffeine | Chemical solvent? |
|---|---|---|
| Water process | Water and carbon filtration | No |
| CO2 process | Pressurized carbon dioxide | No |
| Ethyl acetate ("sugarcane") | Ethyl acetate solvent | Yes, naturally derived |
| Methylene chloride | Methylene chloride solvent | Yes |
Why roasters choose water process decaf
- Clean label. Customers increasingly ask how their decaf is made. "Chemical-free" is an easy, honest answer.
- Flavour. A well-made water process decaf keeps the sweetness and body of the original coffee.
- Origin story. Mexico has its own water-based decaffeination, so a Mexican decaf can stay Mexican from farm to bag.
Roasting tips for decaf
Decaf beans start darker and absorb heat faster than regular green coffee, so colour is a less reliable guide. Use a little less heat, watch time and temperature closely, and expect first crack to be quieter.
Frequently asked questions
Is water process decaf completely caffeine-free?
Not completely. It typically removes about 99.9% of the caffeine, leaving only trace amounts.
Does water process decaf taste different?
Good water process decaf tastes very close to the original coffee. Our Mexican decaf shows chocolate, caramel and vanilla with a silky body.