Common Issues in Pour-Over Coffee | Water Flow, Water Stream Practice, Grind Size Selection, Iced Coffee Making

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Common Coffee Brewing Questions and Solutions

Hello everyone! When you're brewing coffee, you often encounter small problems. Yesterday, we summarized beginner issues in Part 1 of common coffee questions. Today, let's continue:

Q&A One

Are there other methods to make iced coffee besides cold drip?

Do you think you can only drink iced coffee if you make cold drip? That's not true! There are many ways to make iced coffee, and cold drip coffee is just one type of cold brew coffee. Besides cold drip, there are also cold brew coffee, Japanese-style iced coffee, iced pour-over, and more.

Like cold drip coffee, cold brew coffee requires time and patience. Cold brew coffee is made by grinding coffee beans, adding room temperature water, and placing it in the refrigerator for about 12 hours. Then, you simply strain out the grounds and it's ready to drink. Unlike cold drip, coffee made this way has a lighter mouthfeel and cleaner flavors.

Japanese-style iced coffee preparation is similar to regular pour-over, except you reduce the usual hot water amount by half and replace it with ice cubes.

Brewing Parameters:

• Test Coffee Beans: Costa Rica Red Wine Natural Process (5th day after roasting)
• Brewing Method: Iced Pour-over
• Grind Size: 4A (BG)
• V60, 18g coffee, water temperature 91°C, water-to-coffee ratio close to 1:14 (100g ice in server)
• 50g water for bloom, bloom time 40s (stir during this period)
• Then add water to 152ml, shake well after brewing until ice melts completely (total water 100+50+102=252g)

Iced Water Brew:

Brewing Parameters:

• Test Coffee Beans: Costa Rica Sweet Orange Estate (5th day after roasting)
• Brewing Method: Pour-over
• Grind Size: 4A (BG)
• V60, 18g coffee, water temperature 91°C, water-to-coffee ratio close to 1:14
• 50g water for bloom, bloom time 40s (stir during this period)
• Add 252ml of 2°C water, stirring continuously during the process, shake well after brewing (total water 50+202=252g)

Iced pour-over involves first blooming with hot water, then brewing with iced water. However, since the extraction rate of ice water is relatively low, you need to extend the time to three minutes.

Q&A Two

Why do beans need to be ground coarser when they produce sharp acidity after extraction? Isn't sharp acidity a sign of under-extraction?

Sharp acidity in espresso doesn't only occur during under-extraction. When under-extracted, the sharp acidity in espresso has a watery feeling because the extraction is incomplete, only extracting surface and easily extractable substances.

However, a long extraction time can also cause sharp acidity because the surface becomes over-extracted while the interior remains under-extracted, resulting in sharp acidity, followed by bitter and astringent notes.

Q&A Three

What causes coffee grounds not to expand during blooming?

Sometimes watching the small "hamburger" expand during blooming brings a mysterious joy, but not all beans will form a small "hamburger." Blooming is simply to release gases from the coffee particles while creating uniform gaps that allow water to pass through quickly and evenly, enabling thorough extraction.

Factors Affecting Bloom Expansion:

1. Freshness of coffee beans. Blooming is for degassing. If coffee beans are stored for too long after roasting, causing the carbon dioxide inside the bean's cells to naturally release, the "hamburger" during blooming won't be very obvious or may not appear at all.
2. Roast level of coffee beans. Lighter roasted beans have less caramelization than dark roasted coffee, producing fewer metabolic byproducts, resulting in weaker respiration. Therefore, less obvious blooming effects or no "hamburger" effect is normal.
3. Grind size of coffee powder. If ground too coarsely, the water contact area with the coffee powder is smaller, naturally weakening the degassing effect.

Q&A Four

Final question: What constitutes a good coffee bed state in pour-over coffee?

Should the coffee bed be concave or flat after brewing? This is a common question among pour-over coffee enthusiasts.

Actually, we might more commonly encounter concave coffee beds when brewing only around a coin-sized center area, while brewing methods that fully extract the entire coffee produce flat coffee beds.

My typical coffee bed for light and light-medium roasts looks like this:

This difference is caused by pouring technique and range. Here's how I understand it: as long as you can extract a delicious cup of coffee, even a convex coffee bed is acceptable! The prerequisite is uniformity, which indicates even water distribution and even extraction. If one side of the coffee bed is higher than the other, or the surface is uneven, it means the water flow impact is uneven, leading to uneven coffee extraction!

Another issue that's been frequently mentioned recently is why some people's coffee beds don't have pits after brewing? Why do the grounds at the edges fall down?

My typical coffee bed for dark roasts looks like this:

My personal view on whether grounds cling to the filter paper during pour-over:

For light to medium roasted beans, I personally prefer all grounds to participate in extraction (even extraction = same time in water), so the ideal state for even extraction is horizontal with no clinging to the filter paper.

For medium to medium-dark roasts, I'll choose grounds that cling to the filter paper, appearing to have small pits or slightly collapsed in the center. I start with a stable, gentle fine water stream that doesn't disrupt the coffee bed, reducing convection for thorough extraction.

So how can you achieve uniform water flow? One word: practice!

How to practice?

First, practice water flow stability, trying to consistently fill a mug with the same size water stream. Note that the water stream should be perpendicular to the table surface, not forming a parabolic trajectory.

Then, based on the first step, practice pouring within a coin-sized circular range, paying attention to parallel circular pouring without sudden ups and downs, as this would cause uneven water flow pressure.

What if my pour-over kettle tends to "splash water" in a parabolic trajectory? What should I do?

As shown in the image above, when parabolic water flow reaches the near point of the kettle, the lower water flow actually washes roughly the middle layer. When circling to the far point of the kettle, it almost reaches the filter paper! Therefore, I suggest that those who have bought this type of pour-over kettle or are accustomed to parabolic water flow try to consciously pull back slightly, keeping the final landing point of the water trajectory near the center. This way, you won't have one side extracting normally while the other side washes against the filter paper!

That's all for today's topic. Welcome to contact us with any questions and suggestions - FrontStreet Coffee will do our best to answer them!

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