Tea raises a lot of questions. We’re here to help.
Whether you’re curious about caffeine, concerned about something you read online, or just trying to brew a better cup, this page offers clear, honest answers grounded in science and industry knowledge.
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It varies considerably — by tea type, steep time, water temperature, and leaf grade. As a general range: black tea 40–70mg per 250mL serving, green tea 20–45mg, white tea 15–30mg. Caffeine is not extractable in a precise or predictable way from a teabag or loose leaf; the numbers on packaging are estimates. Herbal infusions are typically caffeine-free, though yerba maté and guayusa are exceptions.
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Green and white teas are best brewed at lower temperatures — around 70–80°C — to avoid bitterness. Black tea and herbal infusions are typically brewed at or near boiling (95–100°C). Oolong varies by style. Brewing at too high a temperature can over-extract tannins and produce a harsh cup. See our How to Brew guidelines here.
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It depends on the tea. A general guide: black tea 3–5 minutes, green tea 1–3 minutes, white tea 2–4 minutes, herbal infusions 5–7 minutes. Over-steeping increases bitterness and astringency. Start shorter and adjust to your taste — there’s no universal right answer. See our How to Brew guidelines here.
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It means the tea comes from one defined source — a specific country, region, estate, or garden — rather than a blend of sources. It does not automatically mean higher quality, but it does offer traceability and a more specific flavour story.
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Our Commitment to Natural Materials
The Tea & Herbal Association of Canada tea industry’s priority is delivering a safe, high-quality cup of tea. The vast majority of tea bags on the market today are made from paper and plant-based materials, including natural fibres such as abaca (Manila hemp) and wood-pulp cellulose. These are the same types of materials that have been used to brew tea for over a century.
Where heat-seal elements are needed to close the bag, many producers now use polylactic acid (PLA), a plant-derived, compostable bioplastic made from corn starch or sugarcane, not Polypropylene/petroleum based plastic. All materials used in tea bags sold by our members meet the strict food safety requirements set by regulators, including the Canadian, EU, UK and US bodies whose role it is to make sure products are safe to consume.
The Science in Context
In recent years, a small number of laboratory studies have made headlines by claiming that plastic tea bags release billions or millions of micro- and nanoplastic particles into a cup of tea. The numbers were alarming, and consumers understandably had questions. However, independent scientists and the world’s leading food safety regulators have identified serious methodological problems with these studies that call their conclusions into question.
The Hernandez et al. Study (McGill University, 2019)
The most widely cited study, from McGill University (Hernandez et al., 2019), claimed that a single plastic tea bag could release billions of microplastic particles into a cup of tea. A detailed rebuttal published in the same journal by Busse et al., (2020)[1], a team of independent scientists, including researchers from Germany’s Federal Institute for Risk Assessment (BfR), concluded that the study’s methodology was “completely unsuitable for testing microplastics” because there were flaws in the test design, analysis and application compounded by no definition of agreed methodology for testing microplastics. Busse et al., (2020) found:
- The original study’s particle counts were overestimated by 100 to 1,000 times due to a flawed sample preparation technique.
- Most of what were counted as “microplastics” were actually harmless by-products that crystallized during the drying step of the experiment and were then mistakenly identified as plastic particles.
- The BfR also assessed the soluble by-products that migrate into hot water from nylon or PET materials and concluded that they do not pose a health
The Banaei et al. Study (Universitat Autònoma de Barcelona, 2024)
A more recent study from the Universitat Autònoma de Barcelona (Banaei et al., 2024, published in Chemosphere)[2] generated another round of headlines by claiming that commercial tea bags release “millions of nanoplastics and microplastics” that can be “absorbed by human intestinal cells.” While the study employed a broader set of analytical techniques, it shares several of the same fundamental limitations as the 2019 study and introduces additional concerns:
What the study actually found — and what it didn’t
The tea bags tested weren’t typical store-bought products. Two of the three bags came from Amazon and AliExpress — anonymous, unbranded products not representative of the teas you’d buy from established brands in grocery stores. Drawing conclusions about all tea bags from these is like judging restaurant food safety based on anonymous street vendors.
Sample preparation was flawed. The authors took 300 tea bags and had the tea removed. The tea bags were them placed in 600ml water preheated to 95oC with constant stirring peaking at 750 revolutions per minute for an unknown period of time. This does not mimic how we prepare our tea.
The detection method can create false positives. The microscopy technique used in the study is known to produce imaging errors where by-products get mistaken for plastic particles. European food safety regulators, including EFSA, have flagged this exact problem with this type of analysis.
Lab dish results aren’t the same as what happens in your body. The study exposed isolated intestinal cells directly to concentrated particle suspensions. Your digestive system is far more complex — involving food, enzymes, mucus, and gut transit. Particles entering cells in a petri dish is not evidence of harm in a living person.
One of the three bags wasn’t even plastic. The study’s own analysis confirmed that one bag (the supermarket sample) was made of cellulose — a natural plant fibre. Most headlines didn’t mention this, leaving readers with a misleading picture.
The study showed uptake, not harm. There was no assessment of whether particles caused any damage, toxicity, or health effect.
What Regulators Say
Major food safety authorities in the world have assessed the evidence on microplastics in food. Their conclusions are consistent and clear:
Health Canada: “Although the current scientific literature does not identify a concern for human health, there are insufficient data to allow for a robust evaluation of the potential human health risks of ingested microplastics.”[3]
U.S. Food and Drug Administration (FDA): “Current scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health.” (July 2024)[4]
The UK Food Standards Agency (FSA): Has advised that, based on current information, they consider it is unlikely that the presence of these particles in food or drink would cause harm to consumers. (March 2025)[5]
European Food Safety Authority (EFSA): Its 2025 literature review found that actual microplastic quantities from food contact materials are likely lower than many studies suggest, and current evidence does not support reliable exposure estimates. (October 2025)[6]
German Federal Institute for Risk Assessment (BfR): “According to the current state of knowledge, there is no reliable toxicological evidence of health risks from the ingestion of microplastics via food.” (August 2025)[7]
What This Means for Tea Drinkers
Tea is the second most consumed drink in the world after water, and remains safe to enjoy as it is a regulated beverage.
Here is what consumers should know:
- Most tea bags are made from paper and plant-based fibres, not plastic.
- Where food-grade PLA is used, these materials are approved for contact with hot beverages by major regulatory authorities worldwide and have decades of safe use.
- The headline-grabbing particle numbers from the 2019 and 2024 studies have been shown by independent scientists and regulators to be the result of flawed or limited methodology, not an actual safety concern.
- Tea & Herbal Association of Canada members are committed to transparency, safety, and continuous improvement in packaging materials, including the growing adoption of plant-based and compostable alternatives.
The Tea & Herbal Association of Canada encourages consumers with questions about specific products to contact the brand directly. Our members stand behind the safety of their products and welcome the opportunity to share information about the materials they use.
[1]Busse, K. et al. (2020). Comment on “Plastic Teabags Release Billions of Microparticles and Nanoparticles into Tea.” Environmental Science & Technology, 54(21), 14134–14135. https://pubs.acs.org/doi/full/10.1021/acs.est.0c03182
[2]Banaei, G. et al. (2024). Teabag-derived micro/nanoplastics (true-to-life MNPLs) as a surrogate for real-life exposure scenarios. Chemosphere, 368, 143736. https://doi.org/10.1016/j.chemosphere.2024.143736
[3]Environment and Climate Change Canada and Health Canada. (2020). Science Assessment of Plastic Pollution. Cat. No. En14-424/2020E-PDF. https://www.canada.ca/en/environment-climate-change/services/evaluating-existing-substances/science-assessment-plastic-pollution.html
[4]U.S. Food and Drug Administration (FDA). (2024). Microplastics and Nanoplastics in Foods. Published 24 July 2024. https://www.fda.gov/food/environmental-contaminants-food/microplastics-and-nanoplastics-foods
[5]UK Food Standards Agency, Written Answer to Parliamentary Question 40294, March 2025. https://questions-statements.parliament.uk/written-questions/detail/2025-03-21/40294
[6]EFSA. (2025). Literature Review on Micro- and Nanoplastic Release from Food Contact Materials During Their Use. EFSA Supporting Publication EN-9733. https://efsa.onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2025.EN-9733
[7]German Federal Institute for Risk Assessment (BfR). (2025). BfR Assesses Study on Tea Bags and Microplastic Particles. https://www.bfr.bund.de/mitteilung/bfr-bewertet-studie-zu-teebeuteln-und-mikroplastikpartikeln/