How Is Tea Decaffeinated? The CO₂ Method Explained

What Is CO₂ Decaffeination?

When it comes to enjoying tea without the caffeine, not all decaffeination methods are created equal. One of the cleanest, most effective ways to decaffeinate tea—while preserving flavour and aroma—is the CO₂ process.

The CO₂ (carbon dioxide) method uses pressurised carbon dioxide to selectively remove caffeine from tea leaves. Unlike chemical methods, it’s a natural and non-toxic process, making it ideal for high-quality loose leaf decaf tea.

How Does the CO₂ Process Work?

1. Moisture activation
   The tea leaves are first moistened with steam or water to open their pores.
2. Pressurised CO₂ application
   Liquid carbon dioxide is then forced through the leaves under high pressure. CO₂ acts as a solvent, bonding only with caffeine molecules—not with the oils or compounds responsible for taste.
3. Caffeine extraction
   The CO₂–caffeine mixture is passed through a separation chamber, where the caffeine is removed and the CO₂ is recycled for reuse.
4. Drying and finishing
   The leaves are gently dried to return them to their original moisture level, with flavour, aroma, and antioxidants largely intact.

How Does CO₂ Compare to Other Decaffeination Methods?

There are four main decaffeination methods used in tea production:

1. CO₂ Method

 (used in Porter Hill teas)

• ✅ Retains the most flavour and antioxidant content
• ✅ No chemical residue
• ✅ Environmentally friendly
• ❌ More expensive to produce

2. Ethyl Acetate Method

• ⚠️ Uses a natural solvent found in fruit but often derived synthetically
• ❌ Can strip flavour
• ❌ Leaves trace chemical residue
• ✅ Cheaper and more common in mass-market tea

3. Methylene Chloride Method

• ❌ Uses a synthetic solvent banned in many countries for consumer use
• ❌ Leaves chemical residues
• ✅ Preserves flavour well, but with risks

In short, the CO₂ method is the gold standard for decaffeinated loose leaf tea when quality, flavour, and health are non-negotiables.

Why Choose CO₂ Decaffeinated Loose Leaf Tea?

At Porter Hill, our decaffeinated loose leaf teas are chosen not just for quality, but for how they’re processed. Here’s why the CO₂ method stands out:

• No chemicals – Unlike ethyl acetate or methylene chloride methods, CO₂ leaves no trace behind.
• Superior flavour – Because CO₂ doesn’t strip away volatile flavour compounds, the resulting loose decaf black tea or decaf Earl Grey loose leaf tea retains much of its original character.
• Gentle on the environment – CO₂ is naturally occurring and reused in a closed loop, making it a more sustainable decaf option.

Our Favourite Caffeine-Free Loose Leaf Teas

Looking to unwind without the buzz? Try our range of loose decaffeinated teas, including:

• Loose leaf decaf chai tea – All the spice, none of the caffeine.
• Loose decaf green tea – Light, vegetal and easy on the nerves.
• Loose decaf black tea – Classic British brews, just without the kick.
• Decaf Earl Grey loose leaf tea – The same fragrant bergamot notes, minus the jitters.

We also stock naturally caffeine free loose leaf teas, like chamomile, rooibos, and peppermint, for a soothing sip any time of day.

Bottom Line

The CO₂ decaffeination process is the gold standard for preserving quality while removing caffeine. Whether you’re caffeine-sensitive, cutting back, or simply want a calming evening ritual, Porter Hill’s loose leaf decaf teas are the perfect choice.