Does Brewing Tea Remove Heavy Metals From Water? What the Research Found
Posted by Ricardo R. Matos, Founder of Tea The World on May 4th 2025
Quick answer: Yes, a little. A 2025 study from Northwestern University found that brewing tea pulls some heavy metals out of the water. In a typical cup (one mug of water, one tea bag, steeped 3–5 minutes), tea removed an estimated 15% of the lead. Longer steeping removed more. But the researchers are clear: tea is not a substitute for a water filter.
What the Study Did
The study, led by materials scientist Vinayak Dravid with first author Benjamin Shindel, was published in ACS Food Science & Technology in February 2025. The team added known amounts of lead, cadmium, chromium, copper and zinc to water, heated it to just below boiling, and steeped different teas for times ranging from a few seconds to 24 hours. They then measured how much metal was left in the water.
They tested black, green, oolong and white teas, plus chamomile and rooibos, in both loose leaf and commercial tea bags.
How It Works
Tea leaves naturally adsorb metal ions: the metals stick to the surface of the leaves. When you remove the leaves or the bag, some of the metal leaves the water with them. The more surface area the leaves have and the longer they sit in the water, the more metal they can capture.
What Made the Biggest Difference
- Steeping time mattered most. Longer steeps captured more metal. The researchers noted that very long steeps, like overnight iced tea, could remove most of it.
- Tea type and loose vs. bagged mattered only a little. Finely ground black tea captured slightly more than whole leaves, likely because of its larger surface area.
- The bag material mattered. Empty cellulose bags captured metals well, while cotton and nylon bags captured very little.
- The 15% figure applies to lead levels up to 10 parts per million and depends on the ratio of tea to water.
What This Does and Doesn’t Mean
- It’s a small bonus, not protection. The researchers said they are not suggesting people use tea as a water filter, and that brewing tea will not solve a contaminated water problem. If you are concerned about lead in your water, test it and use a certified filter.
- Health effects are unproven. The authors called any link between tea drinking and population health outcomes speculative and in need of further research.
- Don’t over-steep for this reason. Steeping far longer than recommended makes hot tea bitter. Brew for flavor; any metal capture is a side benefit.
What About Metals in the Tea Itself?
Tea plants, like all plants, can take up trace minerals and metals from the soil they grow in. That’s why sourcing matters: choose teas from sellers who work with reputable growers and quality-tested supply chains, and start with clean, filtered water.
The Takeaway
Brew tea the way that tastes best: right temperature, right steep time, clean water. If your tea also captures a bit of lead along the way, that’s a welcome extra, not a reason to skip a proper water filter.
For brewing guidance, see How to Brew Loose Leaf Tea, our Tea Temperature Chart and How Long to Steep Tea.