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Essential Coffee Terminology Every Beginner Must Know! What are By-pass, Crema, Geisha, and Guanhua?

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Logically speaking, every industry has unified terminology for specific things, which we describe as "professional terminology"! Of course, coffee is no exception. Many baristas or friends use these terms effortlessly in conversation, but once we don't understand their meanings, we can feel left out of the discussion.

Honestly speaking, every industry has unified terminology for specific things, which we describe as "professional terms"! Of course, coffee is no exception. Many baristas or friends skillfully use these terms in conversation, but if we don't understand their meanings, communication can easily lead to misunderstandings!

Therefore! Today, FrontStreet Coffee is here to explain some of the more common professional terms in our coffee industry. Additionally, each term's subtitle comes with a link to more detailed explanation articles, hoping to help everyone learn and communicate about coffee more effectively!

Coffee Bean Section

Arabica: One of the world's three major coffee varieties, the small-bean species. It originates from Ethiopia, but before the 18th century, people always thought this variety came from Arabia because it was monopolized by Arabians at that time! Therefore, when botanist Linnaeus named it using the binomial nomenclature system, he designated Arabia as its place of origin, naming it "Coffea arabica L."! If Teacher Linnaeus had known its origin was Ethiopia before naming it, this variety probably wouldn't be called Arabica~

Robusta: One of the three major varieties, the medium-bean species, originating from the Congo Basin region on the west coast of Africa, abbreviated as "Robusta beans." Due to its extremely strong disease and pest resistance characteristics, it is widely cultivated. However, because its caffeine content is too high, resulting in poor flavor, it is mostly used for commercial beans or as raw material for instant coffee, freeze-dried coffee, and other coffee products!

G1/G2/G3: These are green bean grade identifiers in most coffee-producing regions! It's worth noting that these grades don't refer to flavor differences in coffee beans, but rather to the number of defects! In a 300g sample, the grade is assigned based on the number of defective beans!

PB (Peaberry): Refers to a coffee bean morphology with a rather special appearance. Typically, one coffee fruit contains two coffee beans. However, some undernourished coffee fruits can only nurture one specially-shaped coffee bean! Because of its unique appearance, it is separately sorted and sold at high prices as PB grade!

Processing Method: Refers to the post-harvest processing of coffee beans. Specifically, it's the operation of removing all impurities except the coffee beans from the coffee fruit! At the same time, it's also an important step that affects coffee flavor!

Geisha: The current king of the coffee kingdom! Because this variety has extremely rich floral and fruity aromas, with both high recognition and quality, its price has also risen correspondingly! Currently, there are two naming conventions for Geisha on the market: one is Ethiopia's "Gesha"; the other is Central America's "Geisha," represented by Panama.

Hua Kui: A native variety produced in remote areas of Ethiopia that defeated many Geishas and ranked high in a competition. Therefore, when introduced to China, the green bean supplier gave it the name "Hua Kui" (top performer in Japanese geisha), attempting to become the first bean to defeat the "Geisha" (Geisha's translation in Taiwan)!

Coffee Cultivation Belt: Coffee cultivation has extremely high requirements for climate and environment, therefore, not all land can grow coffee! The areas between 25° south latitude and 25° north latitude on Earth have suitable climates, no frost, and very abundant annual rainfall, making them very suitable for coffee cultivation, thus called the "Golden Cultivation Belt" for coffee!

Heirloom: Refers to the collective name for thousands of coffee varieties in Ethiopia that have not yet been identified by people! This is a name specially established by the Ethiopian government to prevent people from stealing coffee varieties! A bag of Heirloom coffee beans on the market will contain countless different varieties of coffee beans, so their sizes often vary significantly!

Coffee Sensory Section

Cupping: A method of coffee tasting! It uses the extraction method with the least human intervention to release the coffee's flavor, which allows maximum appreciation of the coffee's most original flavor!

Slurping: A way of drinking coffee! By drawing coffee in quickly through closed lips and atomizing it, this allows the coffee to cool down at the fastest speed, thereby enabling the senses to fully experience the coffee's flavor!

Dry Aroma: Refers to the aroma emitted by coffee beans after grinding, which is more pronounced than the aroma of unground coffee beans!

Wet Aroma: Refers to the aroma released when coffee beans are ground into powder, come into contact with water to form coffee liquid!

Flavor: Refers to the aromas and tastes we can perceive and associate with concrete foods during the process of tasting coffee!

Aftertaste: Refers to the coffee aroma and taste remaining in the mouth after swallowing coffee!

Body: Refers to the mouthfeel of coffee, which is the "weight sensation" of coffee liquid in the mouth.

Pour-Over Coffee Section

Pour-over ABC Set: Refers to the ACAIA electronic scale, Brewista pour-over kettle, and C40 Commander hand grinder. Due to their excellent quality, they are known as the three giants of the pour-over world by coffee enthusiasts!

Extraction: Refers to using water as a medium to dissolve the aromatic substances from coffee! Brewing, steeping, and drip filtering are all different methods of coffee extraction!

Under-extraction/Over-extraction: Refers to two negative manifestations of coffee liquid after the extraction process is complete. The Golden Cup Experiment indicates that good coffee extraction rates are generally in the range of 18%-22%. Below 18% is under-extraction, while above 22% is over-extraction! Of course, this data cannot truly represent whether a cup of coffee tastes good, because whether a coffee tastes good still needs to be determined by our own tasting!

Brew Ratio: Unless specifically stated otherwise, it refers to the ratio of coffee grounds to water used during extraction! This is what we commonly refer to as the powder-to-water ratio. For example, 1:15 means that for every 1g of coffee grounds used, 15ml of water should be used for extraction!

Bloom: Refers to using a small amount of hot water to moisten the coffee powder layer in the initial stage of extraction, allowing it to release gas, which will provide better extraction conditions for the subsequent hot water! Generally, twice the amount of water as the powder is injected for a 30-second bloom!

By-pass: Refers to bypass water, a rather special coffee extraction method! The general idea is that during brewing, some water will not participate in the extraction but will directly mix with the extracted coffee liquid! To put it more simply—it's diluting with water! Its purpose changes according to different situations!

Espresso Coffee Section

Espresso Coffee: Refers to coffee extracted through an espresso machine! Also refers to various coffee products made using this coffee as a base!

Combo: Means combination or set. In coffee, a Combo refers to making two or more different drinks using one type of bean, assembling them together—that's a Combo.

SOE: Full name "Single Origin Espresso," refers to espresso made from coffee beans from a single origin, so don't ask questions like "Can SOE be used for pour-over."

Crema: Refers to the golden-yellow foam floating on the surface after espresso extraction, commonly called "oil" in our country. It mainly consists of carbon dioxide and coffee's aromatic substances! Because it contains extremely fine powder, tasting it alone will reveal a certain bitterness!

Blend Coffee: Refers to coffee bean products made by combining beans from more than two producing regions! Generally, the main reasons for blending are high cost-effectiveness, high stability, and high versatility!

Coffee Resting: Refers to the period of allowing coffee beans to sit so that the abundant carbon dioxide inside can naturally escape. The benefit of doing this is that coffee beans with large amounts of carbon dioxide released can be better extracted by hot water, thereby obtaining fuller coffee flavor! Generally, the resting period for pour-over coffee beans is 4-7 days, while for espresso beans it's 7-15 days.

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