How Much Caffeine is in Unsweet Tea?

December 1, 2025 •

4 min read

While a typical 8-ounce cup of unsweetened black tea contains roughly 40 to 60 mg of caffeine, the amount can fluctuate significantly based on several factors, including the type of tea and brewing method. Knowing how much caffeine is in unsweet tea helps you manage your daily intake and choose the right brew for your needs.

Quick Summary

The caffeine content in unsweet tea varies widely, primarily depending on the tea type (black, green, white, herbal), brewing temperature, and steeping time. Understand these key factors to accurately estimate caffeine levels in your beverage and make informed choices for your consumption.

Key Points

Black Tea has the highest caffeine: Unsweetened black tea typically contains 40-70 mg of caffeine per 8 oz, while green tea has less, and white tea has the least among true teas.
Brewing method is crucial: The hotter the water and the longer the steeping time, the more caffeine is extracted from the tea leaves.
Cold brewing lowers caffeine: Making unsweet tea via the cold brew method results in a smoother taste and lower caffeine content compared to hot brewing.
Herbal teas are caffeine-free: Brewed from herbs, fruits, or flowers, unsweetened herbal infusions contain no caffeine and are naturally stimulant-free.
Packaged tea caffeine varies widely: For bottled or canned unsweet tea, always check the label, as caffeine content can differ significantly by brand.
Decaf tea still has trace caffeine: While decaffeinated teas have most caffeine removed, they are not entirely caffeine-free and may contain 1-5 mg per serving.

Understanding Caffeine Levels in Unsweet Tea

Unlike coffee, which generally has a more consistent caffeine level, the amount of caffeine in unsweet tea is a variable science. Your cup of unsweet tea can contain anywhere from 0 mg to over 70 mg of caffeine, depending on multiple factors. Understanding these influences allows you to better control your caffeine intake, whether you're seeking a robust morning boost or a gentle afternoon lift.

The Impact of Tea Type

The most significant factor determining the caffeine level in your unsweet tea is the variety of tea leaves used. All "true" teas—black, green, oolong, and white—come from the Camellia sinensis plant, but they are processed differently, which affects their final caffeine concentration. Herbal teas, or tisanes, are not from this plant and are typically caffeine-free.

Black Tea: Known for its robust flavor, black tea is fully oxidized and generally contains the highest caffeine content, typically between 40-70 mg per 8-ounce serving. Varieties like Assam tend to be higher in caffeine than more delicate Darjeeling.
Green Tea: Less processed than black tea, green tea has a moderate caffeine level. A standard 8-ounce cup usually has 20-45 mg of caffeine. Matcha, a powdered green tea where you consume the whole leaf, is an exception, offering a much higher caffeine dose.
White Tea: Minimally processed and made from the youngest leaves and buds, white tea often has the lowest caffeine content, usually ranging from 15-30 mg per 8-ounce cup. However, some specialty white teas made with more buds can have higher levels.
Herbal Tea: Brewed from fruits, flowers, or herbs, herbal infusions like chamomile or peppermint contain no caffeine. They are an excellent choice for a calming, unsweetened beverage at any time of day.

Brewing Method Matters

How you prepare your unsweet tea also plays a crucial role in its final caffeine level. A longer steeping time and higher water temperature will extract more caffeine from the leaves.

Hot Brew: The traditional method of brewing with hot or boiling water is most efficient for caffeine extraction. Longer steeping times (e.g., 5 minutes versus 2 minutes) lead to a higher concentration of caffeine.
Cold Brew: Steeping tea leaves in cold water over an extended period results in a smoother, less bitter flavor and a lower caffeine level. This is because the cooler water extracts caffeine more slowly.
Loose Leaf vs. Tea Bags: Tea bags often contain broken tea leaves (fannings and dust), which have a larger surface area and release caffeine more quickly than whole loose-leaf tea. This can result in a quicker caffeine infusion from a tea bag, though the total caffeine can still vary.

Factors Influencing Your Brew

Beyond the type of tea and brewing method, several other variables can subtly influence the caffeine content:

Leaf Grade and Size: Younger tea leaves and buds typically contain more caffeine than older, larger leaves. The size of the leaf also impacts extraction speed, as smaller, broken leaves in tea bags release compounds more rapidly.
Growing Conditions: The specific cultivar of the tea plant and its growing environment, such as sunlight exposure, can affect the caffeine concentration in the leaves.

Comparison of Unsweet Tea Caffeine Content


Tea Type (Unsweetened)	Average Caffeine per 8 oz	Notes
Black Tea	40-70 mg	Fully oxidized; strong, rich flavor.
Green Tea	20-45 mg	Less processed; offers a calmer, focused energy.
Matcha (Green)	35-88+ mg	Ground whole leaves are consumed, significantly increasing caffeine.
Oolong Tea	30-60 mg	Partially oxidized; caffeine content is between black and green tea.
White Tea	15-30 mg	Minimally processed; generally lowest caffeine among true teas.
Herbal Tea (e.g., Peppermint, Chamomile)	0 mg	Naturally caffeine-free; a good option for evening drinks.
Decaffeinated Tea	1-5 mg	Most caffeine is removed, but trace amounts may remain.

Conclusion: Tailoring Your Caffeine Experience

Ultimately, the amount of caffeine in unsweet tea is not a single, fixed number but a range influenced by your specific choices. By selecting your preferred tea type and mastering the brewing technique, you can control the caffeine level in your unsweetened brew. For a high-caffeine start to the day, opt for a hot-brewed black tea with a longer steep time. For a mellow afternoon drink, a cold-brewed green or white tea is a better choice. And for a completely caffeine-free option, herbal infusions provide a refreshing alternative. Understanding these factors empowers you to make a beverage that perfectly suits your energy needs and personal taste preferences. With a bit of knowledge, you can become your own barista, creating the ideal unsweetened tea experience every time.

Visit the Center for Science in the Public Interest's caffeine chart for additional insights into various caffeinated beverages.

Frequently Asked Questions

Yes, unsweet tea derived from the Camellia sinensis plant (black, green, white, oolong) naturally contains caffeine. The exact amount depends on the tea type and how it is brewed.

Unsweetened black tea generally contains more caffeine than unsweetened green tea. An 8-ounce cup of black tea typically has 40-70 mg, while green tea contains 20-45 mg.

The caffeine content is similar to its hot counterpart if brewed with hot water and chilled. However, cold-brewed iced tea, steeped in cold water for a longer duration, will have a lower caffeine concentration.

For low caffeine, opt for white tea or, for a completely caffeine-free option, choose unsweetened herbal teas like chamomile, peppermint, or rooibos.

Yes, steeping time is a key factor. The longer you steep the tea leaves, the more caffeine is released into the water, resulting in a higher caffeine content.

Many brands of bottled unsweetened tea, particularly black or green tea, do contain caffeine. It is always best to check the nutritional label for the specific caffeine content.

Yes, you can reduce caffeine by using a shorter steeping time, a cooler water temperature (cold brewing), or by switching to a tea type naturally lower in caffeine, like white tea.