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Is your pour over coffee tasting a little too sour for your liking? Don't worry, you're not alone. Our latest blog post explores the causes and solutions behind this common issue. From adjusting your grind size to changing your water temperature, we've got you covered. Get ready to say goodbye to sour coffee and hello to a perfectly balanced cup every time.

Understanding Sour Coffee

Sour vs Bitter

Sour and bitter are two distinct tastes that can occur in coffee. While sourness is associated with acidic compounds, bitterness results from alkaloids and other compounds in coffee. It's crucial to differentiate between these tastes to determine the cause of a sour or bitter cup of coffee. Sour coffee usually has a sharp, tangy flavor, whereas bitter coffee has a harsh, unpleasant aftertaste.


Under-extraction occurs when not enough flavor is extracted from the coffee grounds during brewing. Insufficient extraction can lead to a sour taste, as the naturally occurring acidic compounds in coffee beans are extracted before the desirable, sweeter compounds. The causes of under-extraction in pour-over coffee include:

  • Incorrect grind size: Using too coarse a grind will result in under-extraction. For pour-over coffee, a medium-coarse grind resembling sea salt is recommended.
  • Water temperature: Water that is too cold will not extract the coffee effectively, causing sour flavors. Aim for a water temperature of at least 85°C (185°F) to ensure proper extraction.
  • Brewing time: If the brewing process is too short, not enough flavor will be extracted from the coffee, leading to a sour taste.


On the other hand, over-extraction is when too much flavor is taken from the coffee grounds, resulting in a bitter taste. Over-extraction in pour-over coffee can be caused by the following factors:

  • Incorrect grind size: Using too fine a grind will cause over-extraction and bitter flavors. As mentioned earlier, a medium-coarse grind is recommended for pour-over coffee.
  • Water temperature: Water that is too hot can lead to over-extraction, causing your coffee to taste bitter. It's essential to maintain a consistent water temperature between 85°C (185°F) and 96°C (205°F) for optimal extraction.
  • Brewing time: If the brewing process takes too long, it can lead to over-extraction and bitter flavors.

To avoid both under-extracted and over-extracted coffee, experiment with the grind size, water temperature, and brewing time for your specific coffee beans until you find the right balance. This will help you achieve a flavorful, well-rounded cup of pour-over coffee without the unwanted sour or bitter flavors.

Factors Affecting Coffee Taste

Coffee Beans and Roast Level

The type of coffee beans and their roast level play a crucial role in determining the taste of your pour-over coffee. Beans that are under-roasted can taste grassy and sour, while over-roasted beans might give a burnt taste. Light roasts tend to have brighter, more acidic flavors, while dark roasts tend to be richer and bolder. It is essential to choose fresh, specialty coffee beans that suit your taste preferences for an ideal pour-over experience.

Water Temperature

The temperature of the water used in the brewing process significantly impacts the extraction of flavors from the coffee grounds. Too low of a water temperature (below 85°C/185°F) may result in under-extraction, leading to a sour taste. On the other hand, excessively hot water can cause over-extraction and bitterness. To achieve a balanced flavor, it is recommended to use water at a temperature between 90°C-96°C (195°F-205°F).

Grind Size

Using the correct grind size for your pour-over coffee is vital for optimal extraction. If the grind is too coarse, it results in faster water flow through the grounds, leading to under-extraction and a sour taste. Conversely, if the grind is too fine, water will flow through more slowly, causing over-extraction and bitterness. Experimenting with different grind sizes can help you achieve the desired taste in your pour-over coffee.

Brewing Process

The brewing process for pour-over coffee should be consistent and controlled. Factors such as pouring technique, water flow rate, and brew time influence the extraction of flavors from the grounds. If the brew time is too short, the coffee will taste sour, while a lengthy brewing process may result in bitterness. Ensuring a consistent grind and maintaining an appropriate water temperature are essential to achieving a well-balanced flavor.

Coffee to Water Ratio

Maintaining the right coffee-to-water ratio is an essential factor in influencing the taste of your pour-over coffee. An ideal ratio is approximately 1 gram of coffee for every 16-18 grams of water. Using too much water can lead to a weak, sour taste, while not using enough water can cause strong and bitter flavors. Experiment with ratios tailored to your preferences to find the perfect balance for your pour-over coffee.

Perfecting Your Pour Over Technique

Using Correct Water Temperature

One critical aspect of pour over coffee brewing is the water temperature. To avoid sour coffee, the brewing water should be above 85°C/185°F to allow for proper extraction of coffee flavors. A common method to reach the right temperature is to bring the water to a boil and then let it stand for 30 seconds. One may also heat fresh water to 200 F, which promotes a more efficient and faster brew.

Selecting the Right Filters

The choice of filters for pour over coffee brewing can affect the taste of your coffee. Using the right filter, whether it's a paper filter or metal one, can help you avoid the sour taste that under-extracted coffee can yield. Always ensure your filters are clean and free from residue, and choose the type of filter that works best with your brewing method – be it a Hario, Chemex, or any other pour-over coffee maker.

Adjusting Grind Size and Surface Area

Maintaining the right grind size and surface area is essential to avoid sour coffee. Pour over coffee calls for a medium-coarse grind to encourage proper extraction. If the grind size is too fine, you might end up with over-extracted, bitter coffee, while too coarse of a grind can result in sour or under-extracted coffee. Experimenting with the grind size can help you find the right balance for your preferred brewing technique.

Optimizing Brew Time

The brewing time for pour over coffee is an important factor in achieving the perfect cup of joe. A sour cup of coffee can be a result of insufficient brewing time. To avoid this, one needs to strike the right balance between brewing time and the coffee-to-water ratio. A general guideline for a starting point is 13-18 grams of water per gram of coffee. Additionally, pouring the water evenly and consistently can ensure the extraction process is consistent throughout.

Comparing Brewing Methods

Pour-over coffee is just one of many brewing methods available, and each method has its intricacies. French press, for example, utilizes an immersion brew method and can produce a different flavor profile compared to pour-over coffee. If you're encountering issues with sour coffee, it may be worthwhile to experiment with various brewing methods and techniques to achieve the ideal taste – and the perfect cup of joe – suited to your palate.

Remember to always keep your brewing equipment clean, including your kettle and coffee maker. This will ensure that your coffee's taste is not negatively impacted by residues or contaminants. With practice, trial and error, you can perfect your pour over coffee technique and enjoy a delicious, balanced cup of coffee every time.

Managing Your Coffee Beans and Equipment

Storing Coffee Beans Properly

It is essential to store coffee beans in an airtight container, away from direct sunlight, to ensure their freshness. Proper storage can help prevent the beans from becoming stale or developing unpleasant flavors. Keep the container in a cool, dry place as moisture and heat can cause the beans to deteriorate more quickly.

Selecting Fresh Beans

Sourcing fresh coffee beans is crucial for a delicious pour-over. Coffee beans tend to lose their flavor and can become sour within 3-4 weeks of being roasted. When purchasing beans, it is recommended to buy whole beans and look for the roasting date on the packaging. Try to acquire beans within two weeks of the roasting date, and avoid using them if they are more than a month old.

Using a Quality Kettle and Carafe

Investing in a quality kettle and carafe is another essential aspect of brewing exceptional pour-over coffee. Utilizing a gooseneck kettle offers more control over the flow and distribution of water, ensuring even extraction of the coffee grounds. A reliable carafe, made from heat-resistant materials, will maintain the ideal serving temperature and help produce a consistent brew.

Grinding Beans Right Before Brewing

Grinding coffee beans immediately before brewing ensures the grounds are fresh and full of flavor. When coffee beans are ground, they release aromatic oils and flavors that can quickly evaporate over time. Old, pre-ground coffee can result in a weak or sour taste. Grind your beans to a slightly finer consistency for pour-over coffee to prevent under-extraction, which can also lead to a sour taste. Adjusting the grind size will help you achieve the best possible extraction and improve the overall flavor of your brew. Keep in mind that the optimal water temperature for pour-over coffee is 199-205°F (93-96°C), and using water at this temperature can significantly enhance the taste.

Addressing Other Potential Issues

Underdeveloped Roasts

Underdeveloped roasts can contribute to a sour pour-over coffee taste. Underdevelopment occurs when the coffee bean's roasting process is stopped prematurely, leading to fruity flavors and higher acidity levels in the brewed coffee. To avoid sour coffee from underdeveloped roasts, ensure that you purchase beans roasted by a reputable source or roast your own coffee and experiment until you achieve the desired flavor profile.

Avoiding Excess Moisture and Oxygen Exposure

Excess moisture and oxygen exposure can cause coffee beans to become stale, leading to sour pour-over coffee. Coffee beans that are several months old or exposed to moisture after roasting can become more prone to sourness. Similarly, coffee beans left in direct sunlight can become dried out and result in a sour brew. To avoid these issues, store your coffee beans in an airtight, opaque container, away from direct sunlight and moisture.

Experimenting with Flavors and Brewing Techniques

Experimenting with various flavors and brewing techniques can help avoid sour pour-over coffee. If you typically encounter sour flavors, consider adjusting the grind size, as the use of coarse grounds can lead to under-extraction and a sour taste. Try a medium grind size instead, especially when brewing with a pour-over method. Adjusting the brewing temperature can also impact the final flavor, as temperatures above 85°C/185°F are essential for avoiding under-extraction.

Brewing time plays a significant role in the extraction process. Extending the brewing time will allow for greater extraction, which can balance the sourness with sweetness and bitterness. Different brewing methods, such as cold brew or French press, can also influence the resulting flavor. Consider experimenting with various brewing techniques to find the one that produces a pour-over coffee with a more balanced taste, avoiding sour notes.

In summary, addressing possible issues with underdeveloped roasts, excess moisture, oxygen exposure, and exploring various flavors and brewing techniques can help improve the taste of your pour-over coffee and prevent sourness. By making adjustments to storage, grind size, temperature, and brewing time, you can ensure a more enjoyable pour-over coffee experience.

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Tony Barlow

Tony Barlow

Majesty Coffee Technical Sales Expert - Meet the Team

Tony Barlow, with over a decade of experience in the coffee industry, is the go-to technical sales expert at Majesty Coffee. He's passionate about helping businesses find the right espresso equipment for their needs.

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