How to Brew Light-Roast Coffee Without Astringency | Coffee Tips & Techniques

 Recently, a friend noticed something interesting: compared to dark-roast coffee, brewing light-roast beans seemed to more easily result in coffee with an astringent taste. Unsure about this observation, he came to Qianjie for some clarification.

So, what exactly is “astringency”? It’s that sensation in your mouth and on your tongue where things feel “gripped” or slightly rough, like a puckering or wrinkled texture. This experience is triggered when certain compounds in coffee interact with proteins in your saliva. Since it’s more of a tactile sensation than a taste, we call it astringency. The situation my friend described isn’t just a misconception—it’s real. Compared to dark-roast coffee, light-roast coffee does tend to extract with more astringency. Of course, brewing method plays a role as well.

The astringency in coffee mainly comes from polyphenols such as tannic acid, tartaric acid, and quinic acid, which is formed from the breakdown of chlorogenic acid. If you notice a distinct astringent taste, it’s likely because these compounds are present in high proportions or have been over-extracted from the beans.

Many factors determine how much of these compounds are present in coffee beans: variety, cultivation, harvesting, processing, and, as my friend mentioned, roasting. The roast level significantly affects how much “astringent matter” remains. The deeper the roast, the fewer astringent compounds remain in the coffee, as many of them are broken down or diminished during the long roasting process. Conversely, lighter roasts retain more of these compounds. That’s why it’s common to notice a more pronounced astringency in light-roast coffees—the polyphenols that cause astringency are largely preserved, making it easier for the brewed coffee to carry that puckering sensation.

However, in most cases, if the beans are fine and the roasting is normal—not underdeveloped or extremely light—brewing with standard methods shouldn’t produce strong astringency. A noticeable astringent taste usually appears when your brewing parameters aren’t suited to the beans, causing either under-extraction of flavorful compounds or over-extraction of astringent ones.

So, what does improper brewing that increases astringency look like? Simply put, it’s under-extraction or over-extraction. Light-roast beans are generally trickier to brew than dark-roast ones. Light-roast beans are denser, so if your brewing parameters result in low extraction efficiency, the positive flavor compounds won’t fully dissolve. Without enough flavor to balance the astringent compounds, the astringency becomes prominent. You may also notice unpleasant notes like hay-like or sharp flavors.

Common causes of under-extraction include too coarse a grind, water that’s too cool, too short a brew time, or insufficient stirring. But as Qianjie points out, over-extraction can also lead to noticeable astringency. Once the desirable flavors are fully extracted, continuing to brew will dissolve more of the less pleasant compounds, including those that produce astringency. Because our senses are very sensitive to these undesirable notes, even a small amount is noticeable.

Factors that lead to over-extraction are essentially the opposite: too high a water temperature, too fine a grind, excessive stirring, or a brew time that’s too long. When brewing light-roast coffee, over-extraction often happens because the brew time unintentionally gets extended. Light-roast beans are denser and are often ground finer, so water penetrates more slowly. Improper brewing can clog the grounds, slow the water flow, and prolong extraction, resulting in over-extraction and pronounced astringency.

Now, here’s how Qianjie avoids astringency when brewing light-roast coffee. He once shared this technique, which, while not perfect, provides some useful guidance.

For this brew, Qianjie used beans from his Tmall/Taobao store: the washed Yirgacheffe Guoding! These beans are grown at high elevation in Ethiopia’s Yirgacheffe region and are relatively light-roasted with high density—a great representative of light-roast coffee. Qianjie favors these beans for their clear floral notes and bright fruit flavors.

To brew well, you need to pay attention not just to extraction parameters but also to pouring technique. The density of the beans prolongs extraction, so reducing stirring can help lower the extraction efficiency and prevent grounds from clogging the filter, ensuring proper water flow.

Here are the parameters:

• Coffee dose: 15g

• Grind: EK43 set to 10 (sugar-like texture), 70–75% passing through a #20 sieve. If unsure about your grinder, err on the finer side, as long as the puck doesn’t become muddy.

  

• Brew ratio: 1:15 (15g coffee to 225ml water)

• Water temperature: 92°C

• Filter: V60

First, pour twice the weight of the coffee in water to bloom for 30 seconds, releasing CO₂ from the beans.

Then, pour with a moderate flow, starting at the center and slowly spiraling outward. Stop before reaching the edge of the filter, and make small in-and-out circles. This first pour totals 100ml.

For the second pour, once the first pour has seeped through, pour 50ml of water in small circular motions from the center.

Finally, pour the last 45ml of water at a steady central point without stirring. This prevents extraction efficiency from rising due to prolonged contact.

Total brew time: 2 minutes 25 seconds. While slightly longer than Qianjie’s usual brews, the extraction was just right—no under-extracted astringency, no over-extracted bitterness, and no harshness. The coffee tastes mainly sweet and acidic, with notes of jasmine, lemon, berries, and oolong tea aromas. The body is smooth, and the finish is long, reminiscent of a floral, fruity oolong tea.

In short, as long as the beans are sound and the brewing parameters are appropriate, you’re unlikely to end up with coffee that tastes noticeably astringent.