Before starting each cup, the head of the espresso machine must be flushed, according to most espresso machine reviews. This clears any old coffee from the screen, and allows fresh water to flow.

Flushing for 3-5 seconds should be enough for E61 Brew Group equipped machines, even less for double boilers.

After inserting the portafilter with tamped grounds into the machine, turn to make sure it is properly secured.

Once the extraction process begins, you will see a stream that is thin and dark. As it moves through the process, the stream will lighten and thicken a bit.

If you see a pale, almost transparent stream, the brewing process should be finishing up. This should take around 25 seconds. If it takes more or less time, adjust your grinder accordingly.

Ideally, a thin layer of crema will appear on the top of your cup to indicate that the pull has been successful. This crema will only last for about a minute, revealing the freshness of the beverage.

If you see a blond stream as you are beginning the pull, this is known as “channeling.” This is not good, as water is forcing a hole through the grinds, leading to a severely under-extracted shot.

A single shot of espresso or a “solo” is generally one fluid ounce (30 ml), while a double or “doppio” is usually two fluid ounces (60 ml). A triple or “triplo” rounds out the measurements for standard shots at the three fluid ounce mark (90 ml).

These shots use a proportionate quantity of coffee grounds, around 7-8, 14-16, and 21-24 grams respectively.

The single shot is considered the classic shot volume, being the greatest amount that could effectively be drawn using the older spring lever machines, although the double is now considered to be the standard volume.

Once you get into more advanced espresso brewing techniques, you will find that the taste, texture, and quantity can also be affected by the extraction length or the amount of time over which the espresso is pulled.

This is often confused with the size of standard espresso shots, but the terminology actually refers to the amount of heated water that is allowed to pass through the puck (another name for the coffee grounds held in the portafilter basket) for any given quantity of grounds.

However, merely adjusting the time that the shot is pulled may result in under (weak and/or sour) or over (bitter) extraction. Instead of the amount or weight of grinds being adjusted as in the single/double/triple examples, the particle size of the grounds is modified at the grinder to dial in the espresso pull to the “sweet spot.”

The length of the shot is then adjusted based off of the grind level, to get the taste that is desired.

This technique can produce at least four different types of espresso beverages. The first three include the ristretto, the normale, and the lungo.

The ristretto is believed to be the absolute best and is the smallest portion of pure espresso at just three-quarters of an ounce to one fluid ounce. This drink is generally a 1:1 ratio of coffee grounds to water.

A normale is around two fluid ounces, usually a 1:2 ratio. A lungo is usually a three to four fluid ounce serving, and is normally a 1:3 or 1:4 ratio.

To reiterate as this can be confusing, the grind level of the coffee grounds is fine-tuned, with the ristretto receiving a much finer grind than that of the lungo, with the normale being somewhere in the middle.

A fourth type, one that is much more rare, is the caffe crema. It its generally 4-8 fluid ounces, featuring a much coarser grind than the standard ristretto, normale, or lungo.