TDS只差0.03%，喝起來卻差很多？一支藝妓轉速實測給你看！ Can a 0.03% Difference in TDS Really Change the Taste? A Real Grind Speed Test with Geisha Coffee
目錄：
1. 實測豆子與條件
2. 為什麼 TDS 差這麼小，喝起來差這麼大？
3. 這樣的調速差異有什麼實用價值？從這次測試可以學到兩個重點：
手沖咖啡愛好者常聽到一句話：數據可以接近，味道卻可能天差地遠。這次，我們就用一支藝妓咖啡，搭配 Mahlkönig EK Omnia 可調速磨豆機，實際驗證給你看：當磨豆機轉速改變時，TDS濃度只差0.03%，但實際喝起來的風味與口感，卻是兩種完全不同的體驗。
Coffee enthusiasts often hear the phrase: “The numbers might be close, but the taste can be worlds apart.” This time, we’re putting it to the test — using a Geisha coffee and the Mahlkönig EK Omnia variable-speed grinder to demonstrate that even when the TDS only differs by 0.03% after changing grind speed, the flavor and mouthfeel of the two cups can be entirely different experiences.
實測豆子與條件
Test Coffee & Setup
這次實驗選用的是 衣索比亞 班奇馬吉 露西 藝妓 G1 日曬，豆子本身就以野薑花、接骨木花、熟果、野莓果醬與百香果等細膩花果香聞名，非常適合作為高轉速與低轉速變化的測試案例。
We selected Ethiopia Bench Maji Lucy Geisha G1 Natural, a coffee known for its delicate florals and vibrant fruit notes — like ginger lily, elderflower, ripe fruit, wild berry jam, and passionfruit — making it ideal for comparing high vs. low grind speeds.
沖煮參數設定：
熱水 90°C
總注水量 320 克
悶蒸 40 克，35 秒
Mahlkönig EK Omnia，固定刻度 550
測試轉速：高轉速 1500 rpm vs 低轉速 500 rpm
Brewing Parameters:
Water temperature: 90 °C
Total water: 320 g
Bloom: 40 g for 35 seconds
Grinder: Mahlkönig EK Omnia, fixed grind size 550
Test speeds: High speed 1500 rpm vs Low speed 500 rpm
從表格可見，數字上 TDS 只差 0.03%，萃取率也僅差 0.42%，看似差異極小，但一入口，兩杯卻是完全不同的故事。
Despite the TDS difference being only 0.03% and extraction yield differing by just 0.42%, the two brews tasted dramatically different.
為什麼 TDS 差這麼小，喝起來差這麼大？
Why Can a Small TDS Difference Taste So Big?
許多人習慣把 TDS 當作「濃度指標」，認為差 0.03% 幾乎無感，但事實上，TDS 只是代表萃取液中溶解固形物的百分比，而這些固形物裡頭包含哪些味道成分，才是真正影響口感的關鍵。
Many people think of TDS as a simple concentration number and assume a 0.03% difference is negligible. But TDS only tells you how much total dissolved solids are in the brew — not what those solids are. The real impact lies in the composition of those compounds.
● 高轉速 1500 rpm
磨粉時產生更多細粉、顆粒分布更廣 → 水與粉接觸面積更大 → 酸質、花香等高揮發性物質釋放更多 → 味道表現更明亮、清爽、層次分明，特別適合想凸顯藝妓豆的花香與果酸。
● Grind Speed and Its Flavor Effects: High Speed – 1500 rpm
Produces more fine powder and a wider particle distribution → Greater surface area contact between water and coffee → Extracts more volatile compounds like acids and florals → Taste: Brighter, more structured, and vibrant — ideal for highlighting the floral and fruity character of Geisha beans
● 低轉速 500 rpm
磨粉更溫和、摩擦熱低，細粉生成少 → 研磨分布更集中 → 高揮發物質釋放較保守 → 味道轉而強化甜感與口感厚度，酸質柔和，尾韻更長，喝起來更滑順飽滿。
● Low Speed – 500 rpm
Gentler grinding, lower heat, fewer fines → Narrower particle distribution → Releases volatile compounds more conservatively → Taste: Sweeter, mellower, soft acidity, and smoother with longer aftertaste
這正是 TDS 相近但風味完全不同 的原因：同樣是 1.3% 左右，但組成的芳香化合物比例完全改變。
This is why two brews with nearly identical TDS (~1.3%) can taste completely different — the proportions of aroma compounds are fundamentally changed.
這樣的調速差異有什麼實用價值？從這次測試可以學到兩個重點：
What’s the Practical Value of Grind Speed Control? This Test Teaches Us Two Important Lessons:
1. 轉速是控制風味的「隱形旋鈕」
除了刻度、粉水比與水溫外，轉速也是一個強大的調味參數，讓同一支豆子呈現不同面貌。
1. Grind speed is a hidden flavor dial
Alongside grind size, brew ratio, and water temperature, grind speed is a powerful variable that can reveal different sides of the same coffee.
2. TDS 數據是基礎，感官才是重點
量測幫助確認萃取是否在安全範圍，但最終還是要喝，看杯子裡的表現是否達到預期。
2. TDS is foundational, but sensory is everything
TDS readings help confirm you’re within a reasonable extraction range, but ultimately, your palate should decide whether the cup expresses the desired flavor.
以 班奇馬吉 露西 藝妓 G1 日曬 為例，高轉速讓人喝到更明亮、花果調奔放的層次感；低轉速則帶來柔和厚甜、焦糖般的收尾，適合喜歡滑順口感的人。所以，當探索更多豆子的潛力時，不只是著重濃度數字，試著調整轉速，讓手沖更好玩、更多變，也更能用杯中的咖啡說故事。咖啡裡的細節，往往藏在這些看似微不足道的小參數裡。下一次手沖，不妨換個轉速試試，手搖磨豆機也可以搖快一點、或搖慢一點，看看你的杯子裡會冒出什麼新驚喜！
Using Bench Maji Lucy Geisha G1 Natural as the test case: High speed delivers a bright, floral, and fruit-forward profile; low speed produces a smoother, sweeter, more mellow and a caramel-like finish, ideal for those who enjoy creamy textures. So, when exploring a coffee’s full potential, don’t just fixate on the TDS number. Try adjusting grind speed, it makes brewing more fun, expressive, and versatile, a cup of coffee can tell a good story. The magic of coffee often lies in the small, overlooked details. Next pour-over brew, switch up the speed, and see what happens. Even with a manual grinder, try turning faster or slower — you might discover surprising new dimensions in your cup.
│延伸閱讀：磨豆機轉速對咖啡甜感與酸感的影響
│Further reading: The Impact of Grinder Speed on Coffee's Sweetness and Acidity
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