Decaffeinated Tea Explained: How It's Made and What Actually Remains
Quick answer: Decaffeinated tea starts life as ordinary black, green or white tea picked from the tea plant, Camellia sinensis, and has most of its caffeine removed afterwards by washing the leaves in a permitted solvent. Decaf tea still contains a little caffeine: a peer-reviewed laboratory study found decaffeinated teas had less than 12 mg per serving, against 14 to 61 mg in regular tea. UK food law names which solvents may be used and caps what can remain. Rooibos and most herbal infusions work differently: they are naturally caffeine-free because they were never made from the tea plant in the first place.
What does "decaffeinated" actually mean for tea?
Decaf tea is not a separate plant, a special low-caffeine cultivar, or a different way of growing the crop. It is the same leaf used for black, green, white and oolong tea, just with an extra manufacturing step added near the end of the process to take most of the caffeine back out again. The UK Tea & Infusions Association describes the method in plain terms: producers "wash" the tea leaves towards the end of production in an organic solvent, and the method is "strictly governed by legal limits" (source).
That order matters for anyone comparing labels. A pack of decaf English Breakfast, for instance, is still black tea; the "decaf" on the label refers purely to that final extraction step, not to a different plant, region or grade of leaf.
How is tea actually decaffeinated?
Food law sets out which solvents may be used. Under the Food Additives, Flavourings, Enzymes and Extraction Solvents (England) Regulations 2013, carbon dioxide and ethyl acetate both appear among the extraction solvents that can be used across food production generally, provided they are used under good manufacturing practice, a standard the regulations define as leaving behind only residues "in technically unavoidable quantities presenting no danger to human health" (source). Three further solvents are named specifically for "decaffeination of, or removal of irritants and bitterings from coffee and tea", each with a legal maximum residue: methyl acetate and ethylmethylketone at 20 mg/kg in the tea, and dichloromethane at 5 mg/kg in the tea (2 mg/kg in roasted coffee) (source).
Why does it matter which solvent is used?
The law treats solvents differently: some may be used for any food as long as only technically unavoidable residues remain, while others are allowed only for named jobs and with a numeric residue cap. For a shopper, the point is that decaffeination is a defined, regulated process rather than a vague marketing term. If the method matters to you, check the pack or ask the brand which one it uses.
Is decaffeinated tea actually caffeine-free?
No. Decaf tea still contains a little caffeine. A study published in the peer-reviewed Journal of Analytical Toxicology measured caffeine across twenty commercial tea products and found that ordinary white, green and black teas contained between 14 mg and 61 mg of caffeine per 6 to 8 oz serving, while the decaffeinated teas in the same sample contained less than 12 mg per serving (source). Herbal infusions tested in the same study had no detectable caffeine at all, which lines up with the fact that they were never brewed from the tea plant to begin with. The UK Tea & Infusions Association separately notes that ordinary tea already contains roughly half the caffeine of coffee (source), so decaf tea is a further step down again, but not zero.
If you have been told to avoid caffeine for a medical reason, follow your doctor's or midwife's advice on how much is acceptable rather than treating "decaf" as zero.
How does decaf tea compare with rooibos and herbal infusions?
This is where the two routes to "no caffeine" genuinely part ways. Decaf tea is still Camellia sinensis tea with caffeine removed afterwards, which is why it keeps a trace behind. Rooibos and most herbal infusions, sometimes called tisanes, are a different story altogether: the UK Tea & Infusions Association says they are "not derived from the tea plant" and are instead made from herbs, flowers and fruit (source). It lists rooibos, chamomile and liquorice among the infusions that are naturally caffeine free. It also notes that some infusion blends include tea as a minor component, so check the ingredients on a blend (source). If that suits you better, browse our rooibos and caffeine-free collection.
Which should you choose for an evening cup?
If you want something that brews and tastes like real tea, with much less caffeine, decaf black or green tea is the closer match because it is the same leaf with the same brewing rules. Our green teas and classic teas are a good place to start if you choose by tea type first. If you want no caffeine at all, rooibos or a single-herb infusion such as chamomile settles it, though the flavour is different rather than a quieter version of your usual cup.
Decaf tea FAQs
Is decaffeinated tea completely caffeine-free?
No. Laboratory testing of commercial teas has found that decaffeinated teas still contain a small amount of caffeine, less than 12 mg per serving in one peer-reviewed study, compared with 14 mg to 61 mg in regular tea, rather than none at all.
How is the caffeine removed from tea leaves?
Producers add an extra step towards the end of normal tea production and wash the leaves in a permitted solvent that removes most of the caffeine.
Is decaffeinating tea regulated?
Yes, it is a regulated process. UK food law names the solvents that can be used to decaffeinate tea and sets maximum residue limits for some of them, such as 5 mg/kg in tea for dichloromethane.
What is the difference between "decaf" and "caffeine-free" on a tea label?
"Decaf" means the product started life as ordinary tea from the tea plant and had most of its caffeine removed afterwards, leaving a small trace behind. "Caffeine-free" usually refers to rooibos or a herbal infusion, which was never made from the tea plant. Check blends, as some include tea.
Should I choose decaf tea or rooibos if I want to avoid caffeine in the evening?
If you want the closest match to the flavour and ritual of real tea with much less caffeine, decaf black or green tea is the nearer option. If you want to remove any realistic chance of caffeine altogether, rooibos or a single-herb infusion such as chamomile is the more certain choice.
Sources: UK Tea & Infusions Association, Frequently Asked Questions About Tea (tea.co.uk/tea-faqs); UK Tea & Infusions Association, FAQs About Infusions (tea.co.uk/faqs-about-infusions); The Food Additives, Flavourings, Enzymes and Extraction Solvents (England) Regulations 2013, Schedule 6 (legislation.gov.uk); Chin, J.M. et al., "Caffeine Content of Brewed Teas," Journal of Analytical Toxicology, 2008 (pubmed.ncbi.nlm.nih.gov).