How Different Cup Rim Shapes Affect the Taste and Mouthfeel of Pour-Over Coffee

The Impact of Cup Shapes on Coffee Flavor

Cups, as one of the most common vessels in daily life, have different shapes and names accordingly. While there are various cup types, styles, and designs on the market, they ultimately serve practical purposes. FrontStreet Coffee experimented with using different shaped cups for pour-over coffee to determine whether the flavor would be affected differently.

Common Cup Types

1. Open-mouth cups, also known as wide-mouth cups, have large openings, are wider at the top and narrower at the bottom, with the walls slanting outward at approximately 45 degrees, resembling a bamboo hat.

2. Straight-bodied cups have medium-sized openings, with straight walls from the body to the rim, gradually tapering at the bottom.

3. Narrow-mouth cups, also known as Arhat cups, feature concave-shaped openings, bulging bodies, with both the bottom and top narrowing inward.

How Does the Same Coffee Taste in Different Cups?

FrontStreet Coffee first brewed Guatemala's sun-dried La Bella Geisha coffee beans and compared them using the three aforementioned cup types. Ceramic cups with good heat retention properties were selected, and all cups were preheated before drinking.

The brewing parameters used were those from FrontStreet Coffee's store: 15g of coffee grounds, 1:15 coffee-to-water ratio, brewing temperature of 91°C, medium-fine grind (78% passing rate through Chinese standard sieves), and three-stage extraction.

During the aroma assessment phase, the narrow-mouth cup exhibited diverse aromas, with roasted nuts, tropical fruits, and delicate floral notes upon tasting. The straight-bodied cup also had nutty and fruity aromas, though not as rich as the narrow-mouth cup. The open-mouth cup had the faintest aroma.

When tasting the coffee while hot, the straight-bodied cup had the highest concentration, with full-bodied berry sweetness and acidity. The open-mouth cup had more pronounced acidity with some tea-like notes. The narrow-mouth cup had the highest sweetness, making the coffee taste more rounded.

As the temperature decreased, the acidity in the open-mouth cup began to diminish but remained the highest among the three cups. The overall flavor of the narrow-mouth cup declined, while the straight-bodied cup's flavor didn't change significantly from when it was hot.

How Do Different Coffee Varieties Taste in the Same Cup?

To gather more comparative data, FrontStreet Coffee also brewed Brazil's Queen Estate coffee beans (predominantly bitter) and Ethiopia's Yirgacheffe Gudina coffee beans (predominantly acidic). The same standard brewing parameters from their daily operations were used.

Brazil Queen Estate

Open-mouth cup: Nutty aroma, spicy notes, slightly acidic, with a somewhat complex aftertaste as it cools

Straight-bodied cup: High concentration, full-bodied, prominent bitterness, chocolate aroma

Narrow-mouth cup: Rich caramel and cream aromas, prominent sweetness, balanced mouthfeel

Yirgacheffe Gudina

Open-mouth cup: Bright lemon and citrus acidity, rich aromatic profile upon entry, with distinct layers

Straight-bodied cup: High berry acidity, green tea texture, minimal flavor variation

Narrow-mouth cup: Prominent honey and jasmine floral notes during aroma assessment, weakened sweet and sour flavors, thinner mouthfeel

Why Do Different Cup Shapes Produce Different Tastes?

The human tongue can perceive different tastes in various regions - the tip detects sweetness, the sides sense sourness, and the back of the tongue is most sensitive to bitterness.

Open-mouth Cups

When drinking coffee from an open-mouth cup, the coffee liquid has more contact area with air, and the rim's shape causes the coffee to disperse more when entering the mouth. The coffee first flows along the sides and tip of the tongue, making sour and sweet flavors more easily detected and enhancing the brightness of acidity.

The open rim allows coffee to cool faster, making the flavor layers particularly distinct at different temperature ranges. As it cools, the tongue sides become especially sensitive to acidity, which can make bitter-profile coffees taste "complex." Additionally, the open design doesn't concentrate aromas well, resulting in weaker aromatic performance during the assessment phase.

Straight-bodied Cups

The advantage of straight-bodied cups lies in their moderate opening size. The straight design allows coffee liquid to flow concentrated into the mouth, creating a greater sensory impact. Hot to warm coffee has higher concentration, resulting in a fuller, more substantial mouthfeel. Straight-bodied cups perform moderately during aroma assessment, but their elongated body slows the cooling process, preventing rapid flavor changes.

Narrow-mouth Cups

The narrow-mouth design requires us to lift the cup higher while drinking, simultaneously raising the jaw and forming a more forward-focused mouth shape, similar to sipping. This allows the liquid to distribute more evenly in the mouth.

The wide body and concave rim design allow aromas to release at the widest point and then concentrate at the opening, making it highly advantageous for aroma assessment.

During hot to warm temperature stages, perception of various coffee flavors becomes more balanced, enhancing the coffee's smooth texture. Bitter-profile coffees taste fuller, while acidic-profile coffees may seem less layered and thinner in texture.

Which Cup Should You Choose?

Since we now understand that different cup shapes affect coffee aroma, flavor, and mouthfeel, we can select cups that "correspond" to specific flavor profiles to "elevate" our home-brewed coffee!

For brewing coffees that emphasize acidity, we can choose open-mouth cups that make flavor layers more distinct, such as light-roasted acidic beans like Yirgacheffe and Kenya. For dark-roasted bitter-profile coffees like Golden Mandheling and Blue Mountain, narrow-mouth cups that balance mouthfeel are recommended to better appreciate the coffee's richness and aftertaste.

For coffees with prominent aromas, such as FrontStreet Coffee's Musician Series Mozart, Rose Valley, and Flower Moon Night beans, straight-bodied cups' heat retention properties prevent coffee flavors from changing too rapidly due to temperature drops.

Of course, besides different shapes creating different drinking experiences, factors like thickness, material, and volume can also affect the coffee in our hands. If you're a cup enthusiast with various cup styles at home, you can conduct comparative tests like FrontStreet Coffee did to find the cup that suits you best.

For professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style).

For more specialty coffee beans, please add FrontStreet Coffee's private WeChat (FrontStreet Coffee), WeChat ID: qjcoffeex

Important Notice :

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