This is how I make coffee in the morning. As one would hope with routines, both the speed and the results of this one are improving with time.

Espresso is the result of almost-boiling water at high pressure (~8 bars or 116 PSI) being forced at a consistent rate through coffee beans ground to a specific range of fineness.

This video doesn't show the grinding of the beans, distribution and tamping - basically, the first two-thirds of the process. This is just about brewing, the "fun" part.

What you're seeing here is a bottomless or "naked" portafilter (the tool which holds the coffee grounds) versus a traditional model with spouts. The bottomless PF is a great debugging tool for making espresso because you can gauge the quality of your grind, distribution and tamping by watching the brewing process.

When things go right, "pulling a shot" can be a beautiful and somewhat mesmerizing thing to watch. While practically impossible to perfect, the extraction in this video turned out pretty well in regards to the visuals.

Grouphead Flushing

Before extraction, it's recommended to "flush" the grouphead by running water through it. This brings its temperature down toward the target (roughly 200° F, in this case.) Additionally, the water pre-heats the cup.

There should be a minimal delay between flushing and extraction, since the grouphead temperature will quickly rise again if the boiler (heater) is on. I was relatively slow here, as I shot this video a few months ago. These days, I'm faster and there is much less idle time.

Brewing / Extraction

During extraction, it's good to see a deep reddish color, striations or "tiger striping" from the coffee coming out of the portafilter. It shouldn't be glacial, nor gushing in terms of "flow rate" - extremes on either end are undesirable.

Brewing should typically be stopped between 25-30 seconds, or when "blonding" occurs. There are also targets for ratios of extraction, i.e., 20 grams of espresso in 30 seconds and so forth.

I watch extraction runtime, but don't weigh the results to determine extraction ratios etc. Some roasters provide recommended parameters for their beans; e.g., 18.5 grams, with an extraction time of 28 seconds at 200° F.

In this case you're seeing Roastco "Oscuro Nuevo" espresso roast beans, perhaps 19 grams, being used in a 20g VST basket.

Results, Observations and Miscellany

There's a memorable 15:15:15 rule about espresso that I've heard.

• Coffee used within 15 days of roasting • Grounds used within 15 minutes of grinding • Espresso tasted within 15 seconds of extraction

In regards to appearance, good espresso should have deep color with some mottling, minimal bubbles and a solid layer of crema (an emulsification of oils from the beans) on the top; good crema should maintain its structure for around two minutes. If you're using a glass cup, you can also observe the layers as they swirl and settle within the glass.

In regards to taste, good espresso should be almost sweet, typically with hints of chocolate, butterscotch and whatever other colourful language roasters like to use to describe their products. What I look for is a natural sweetness, light acidity and ultimately an absence of excessive bitterness (water temperature too high) or sourness (too low). A one-second difference in extraction time can also have a notable effect on your results, in terms of balance and strength of taste.

I've heard people recommend consuming a shot in three sips, to enjoy the separate layers. Crema is unique in that it's a concentrated mix of the oils in the beans, and can be fairly different than the underlying coffee.

A fresh roast is critical to quality. From my experience, the consistency and quality of extraction goes downhill toward the two week mark. Then again, the last beans from my grinder always seem to produce fairly-runny extractions; perhaps there's something to the weight applied by the beans stacked above during grinding. At present, I go through an 8-oz bag of beans in about a week.

This is effectively what I've learned thus far about making espresso. I get pretty consistent results, and ideally, espresso that is quite tasty. I don't plan on opening a coffee shop any time soon, but I'd like to think I can make something close to my professional neighbours in terms of taste. I think I still make stuff that's a bit on the acidic / bitter side, but I'm working on it.