When I do trainings, sometimes I have students who don't normally drink straight espresso. But, I tell them, drinking straight espresso is now a part of your job. "You don't drink espresso? Well, you do now!"
Think about it: would you want to eat at a restaurant where the chef created specials that he sent out to the guests without ever tasting the recipe once?
Some people are very sensitive to caffeine, and I understand that. For those people I recommend they try small sips of espresso which they can then spit out into a cup. If you want to be really careful about it, you can follow this up by rinsing your mouth out with water or, even better, sparkling water.
Every barista should be tasting his or her espresso every day, without exception. As you taste more and more shots, you start to build a vocabulary for how to analyze the taste. And you begin to notice correlations between certain aspects of the appearance of the espresso and the tastes that go along with it. And, of course, you can track changes as they happen to the blend over time.
When someone drinks a straight espresso for pleasure, I would never dream of telling them how they should or should not consume it. Personal preference! But if you are sampling an espresso purely for flavor evaluation, I have a couple of pointers.
First of all: understand that espresso is a strong beverage. People often react to a strong-tasting compound by calling it "bitter" without reflection. But bitterness and strength are two different things. Try to "taste through" the initital strength of the beverage. Of course, many espresso are bitter, but we want to be able to separate these from those that are sweet, or sour, or salty. So be brave and keep tasting after that initial shock.
The second pointer I give is to always taste beneath the crema. Good espresso should have resilient crema. It's a sign that the fats have been properly emulsified, lending to a rich, smooth mouthfeel that you only get in espresso. But it can taste radically different than the rest of the brew. Essentially, each cup of espresso is two beverages laying one on top of the other, like a black-and-tan: the crema on top of the darker espresso. The crema is CO2, particulate matter, and oils. The darker liquid is mostly water and solubles, with some oils blended in. They taste very different. Always be careful to poke a hole in the crema by blowing on it or scooping with a little spoon.
And that's it! All you need to know to become an expert taster of your own shots. The best lessons come from real life experience, so get out there and start tasting.
For a bonus, check out this interesting video from former World Barista Champion, James Hoffmann. h/t to Nigel.
