☕️ Last Week at Neighbors’: Learning to Taste the Difference Between Sour and Bitter

Last week, our team gathered for a sensory exercise focused on two foundational tastes in coffee that are often confused but play very different roles in how a cup is perceived: bitterness and sourness.

Understanding the difference between these two isn’t just a fun tasting experiment — it’s a critical skill for brewing better coffee, dialing in espresso, and speaking the same flavor language as a team. Here’s what we explored and why it matters behind the bar.

Tasting Bitterness on Its Own

We began by isolating bitterness using Epsom salt, allowing us to experience bitterness without the influence of aroma, sweetness, or acidity.

What stood out immediately was how bitterness builds slowly. Rather than hitting all at once, it lingered and spread across the palate over time. Many of us noticed a drying or slightly chalky mouthfeel, especially toward the back of the tongue. The sensation felt heavy and persistent, reinforcing how bitterness can be subtle at first but gradually overpower more delicate flavors.

This exercise helped clarify why overly bitter coffee can feel exhausting to drink — even if it doesn’t seem aggressive at first sip.

Calibrating Sourness with Citric Acid

Next, we shifted to citric acid to calibrate what sour truly tastes like.

In contrast to bitterness, sourness was immediate, bright, and sharply defined. It hit the palate quickly, increased salivation, and then faded more rapidly. This clarity made sourness easier to identify and describe — especially when compared side by side with bitterness.

Tasting sourness in isolation made one thing very clear: although sour and bitter are often confused in coffee, they feel completely different on the palate when you know what to look for.

How This Translates to Coffee

When we applied these sensations to coffee tasting, an important takeaway emerged: acidity is not inherently a flaw.

When a coffee is brewed correctly, acidity can be intentional and pleasant — adding structure, vibrancy, and clarity to the cup. This is especially true in lighter roasts, where acidity helps express fruit-forward and floral notes rather than tasting sharp or underdeveloped.

The goal isn’t to eliminate acidity or bitterness, but to understand when they’re balanced — and when they’re a sign that something needs adjustment.

What This Means for Dialing In Espresso

This exercise directly supports how we dial in espresso on bar every day.

• Sour espresso often indicates under-extraction — when water hasn’t had enough time or contact to fully dissolve sugars and balancing compounds. The result can taste sharp, thin, or overly bright, much like the immediate sourness we experienced with citric acid.

• Bitter espresso, on the other hand, is often a sign of over-extraction — when water pulls out excessive bitter compounds, leading to a drying, lingering finish similar to the Epsom salt tasting.

With this understanding, adjustments become clearer and more intentional:

• If a shot tastes sour → grind finer, increase extraction time, or adjust dose/yield

• If a shot tastes bitter or drying → grind coarser, reduce extraction time, or adjust yield

Instead of guessing or relying on vague descriptors, this shared sensory awareness gives us clearer cues for dialing in espresso accurately and efficiently.

Why Palate Calibration Matters as a Team

Beyond espresso dialing, this exercise plays a key role in calibrating our palates as a team.

By tasting bitterness and sourness in isolation, we created a shared sensory reference point. This helps reduce individual bias and ensures that when someone describes a coffee as “sour” or “bitter,” we’re all talking about the same sensation.

That alignment allows us to:

• Taste coffee with greater confidence and clarity

• Communicate adjustments quickly between shifts

• Maintain consistency across baristas as coffees and roasts change

• Better explain flavors to guests in an approachable, accurate way

Ultimately, these exercises help us move from subjective opinions like “I don’t like this” to intentional evaluations like “This tastes under-extracted because it’s sharp and sour.”

The more we practice tasting together, the more consistent our coffee — and our communication — becomes.