This batch explores the “Dark Side” of coffee flavors, the physics of water temperature, and the specific grading of Kenyan “C” and “E” beans.
Article 181: The “E” Grade: Kenya’s Elephant Beans
(Category: Coffee Bean Knowledge | Word Count: ~280)
In the Kenyan grading system, most people focus on AA and AB. However, there is a rare and visually striking grade called E (Elephant Beans).
What are they?
Elephant beans occur due to a genetic abnormality where two seeds join together in a single cherry. This results in a massive, oversized bean that often “splits” into two ear-shaped halves during the milling process.
The Roasting Challenge:
Because Elephant beans are so much larger than standard beans, they are difficult to roast. If you mix them with smaller beans, the small ones will burn before the “E” beans are even cooked. Therefore, “E” lots are usually separated and roasted on their own. They tend to have a heavy body and a slightly more “savory” profile compared to the bright acidity of the AA grade.
Article 182: The “Slurry” Temperature
(Category: Brewing Methods | Word Count: ~240)
When brewing pour-over coffee, there is a difference between your Kettle Temperature and your Slurry Temperature. The “slurry” is the mixture of coffee grounds and water inside the brewer.
The Physics:
If you set your kettle to 95^\circ\text{C} and pour it into a cold ceramic V60, the temperature of the slurry will instantly drop to around 85^\circ\text{C} because the ceramic absorbs the heat.
Why it matters:
Extraction happens at the slurry level. If your slurry temperature is too low, you will fail to extract the complex sugars, leading to a thin, sour cup. This is why professional baristas pre-heat their brewers with boiling water and keep the kettle lid closed between pours—to keep that slurry temperature as stable as possible throughout the 3-minute brew time.
Article 183: Understanding “Bitterness” (Good vs. Bad)
(Category: Sensory Skills | Word Count: ~290)
In specialty coffee, “bitter” isn’t always a bad word. We must distinguish between Caffeine Bitterness and Tannic Bitterness.
- Good Bitterness: This is like the bitterness in dark chocolate or grapefruit peel. It provides balance. Without a little bit of bitterness, coffee would taste like sugary fruit juice and lack “kick.” This usually comes from the caffeine itself and light caramelization.
- Bad Bitterness: This is harsh, ashy, and “dry.” It lingers on the back of your throat. This is caused by over-extraction (water too hot or brew time too long) or over-roasting.
The Barista’s Goal:
You want to extract enough to get that “chocolatey” structure, but stop before you pull out the “ashtray” flavors. If the bitterness makes you want to add sugar, it’s the “bad” kind!
Article 184: The “Bypass” Technique
(Category: Brewing Methods | Word Count: ~210)
A “Bypass” is the act of adding plain hot water directly to your finished brew, rather than running it through the coffee grounds.
Why use a bypass?
Sometimes, to get the strength you want, you have to grind so fine that the coffee becomes bitter. Instead, you can brew a very “concentrated” small cup (extracting only the best flavors) and then “bypass” with hot water to reach your desired volume.
This is exactly how an Americano or a Long Black works, but it can also be used in filter brewing to achieve a cleaner, lighter mouthfeel. It allows you to control the strength (TDS) without risking over-extraction.
Article 185: The 3 Stages of Milk Steaming
(Category: Barista Skills | Word Count: ~310)
Steaming milk is often the hardest skill for a student to master. It must be broken down into three distinct phases: - Stretching (Aeration): This happens at the very beginning when the milk is cold. You keep the steam tip near the surface to create “hissing” sounds. This introduces air to create foam.
- Texturing (The Vortex): Once the milk reaches about 37^\circ\text{C} (body temperature), you submerge the wand slightly to stop adding air and start spinning the milk in a circle. This “whirlpool” breaks big bubbles into tiny microfoam.
- Heating: You continue the vortex until the milk reaches 60^\circ\text{C} – 65^\circ\text{C}.
The Common Mistake:
If you “stretch” for too long, the foam will be too thick (like a marshmallow). If you don’t stretch enough, the milk will be watery. The “sweet spot” is usually only 3 to 5 seconds of stretching!
Article 186: What is “C” Grade Coffee?
(Category: Coffee Bean Knowledge | Word Count: ~230)
In the Kenyan grading system, C is the smallest of the main commercial grades (excluding the tiny “T” and “TT” grades). These beans are screened at size 14 or 15 (5.6\text{ mm} to 6.2\text{ mm}).
Is it “lower quality”?
Not necessarily. While “AA” is more expensive because the beans are large and visually beautiful, a “C” grade coffee can have the exact same flavor profile if it comes from the same farm. In fact, some roasters prefer “C” grades because they are denser and can be easier to roast evenly in small machines.
For a barista, “C” grade Kenyan coffee is often the best value for money, offering that classic Nyeri or Kirinyaga acidity at a lower price point than the premium “AA” lots.
Article 187: The “Quenching” Process in Roasting
(Category: Roasting Knowledge | Word Count: ~220)
Once a roaster hits their target temperature, they must stop the cooking process immediately. This is called Quenching.
If the beans stay hot, they will continue to roast from the inside out, even after they are out of the drum. This is known as “coasting” and can turn a perfect Medium Roast into a Dark Roast in seconds.
How it’s done:
The roasted beans are dropped into a Cooling Tray, which uses a powerful fan to suck cool air through the beans while a mechanical arm stirs them. A professional roaster aims to get the beans from 200^\circ\text{C} down to room temperature in under 4 minutes to “lock in” the volatile aromatic oils.
Article 188: Why “Filter” Coffee is Healthier than “Espresso”
(Category: Coffee Education | Word Count: ~260)
Coffee contains natural oils called Diterpenes (specifically Cafestol and Kahweol). Medical research has shown that these compounds can slightly raise cholesterol levels in some people.
The Filter Factor:
When you brew coffee through a paper filter (like a V60, Chemex, or Aeropress), the paper traps almost all of these diterpenes.
When you drink Espresso, French Press, or Turkish Coffee, these oils pass directly into your cup.
For most people, the amount is too small to matter. However, for those monitoring their heart health, paper-filtered coffee is considered the “cleanest” and healthiest way to consume the beverage. It’s another great reason to master the art of the pour-over!
Article 189: Understanding “Total Hardness” (GH)
(Category: Coffee Science | Word Count: ~250)
Total Hardness (GH) is the measurement of Magnesium and Calcium ions in your water. In the world of specialty coffee, Magnesium is the superhero.
The Science of Extraction:
Magnesium is a very “sticky” ion. When water flows through coffee grounds, the Magnesium ions physically “grab” onto the complex acid and sugar molecules and pull them into the liquid.
If your water has zero hardness (like distilled water), there is nothing to grab the flavor, and the coffee will taste weak and sour. If your water is too hard, it will be “saturated” with minerals and won’t have any room to pick up the coffee flavors. The “Golden Zone” is usually between 50\text{ and }150\text{ ppm} of total hardness.
Article 190: The “Cleanliness” of a Barista’s Station
(Category: Barista Skills | Word Count: ~190)
A messy station leads to messy coffee. A professional barista follows the “Clean as you go” rule.
The Checklist: - The Hopper: Should be free of yellow oil buildup.
- The Steam Wand: Should be wiped and “purged” (blown out) immediately after every use. Never let milk dry on the wand!
- The Drip Tray: Should be emptied and rinsed so the bottom of the cups stay clean.
- The Grinder: Stray grounds should be brushed away every few minutes.
A clean station doesn’t just look better; it tells the customer that you respect the ingredients and the craft. If you can see the counter, you are doing a good job!