Selecting the right bean for the right beverage is the first step to pulling a great shot, and often overlooked. Since espresso extraction is a much more concentrated brewing method than other coffee brewing methods, the quality of the bean is very important. Simply put, if the beans being used are poor quality, then the resulting extraction will be just as poor. Just like any other form of cooking, using quality ingredients is imperative to success.
Using fresh beans, opened within the last two weeks, is crucial. Typically we suggest a light/medium roast that is dry and fresh for the most complex flavors.
Grind size is one of the ways flavor is governed, and how the timing of the shot is controlled. When making espresso, the ideal grind size to start with will be a little finer than granulated sugar. You want a shot of about 2.5 oz in 25-30 seconds. If it comes out too quickly, adjust for a finer grind. Too slowly, and you can back out to a coarser setting. You'll start hitting the sweet spot once you notice the grounds clumping together. Once you grind your coffee into your portafilter, you can move onto tamping.
Your dose is going to depend on whether you are making a single, double, or triple shot, as well as the type of brewing equipment you are working with. For instance, the suggested dose for a doubleshot is about 16-18 grams of coffee, depending on the portafilter basket size and your flavor preference.When picking equipment, remember that a higher quality espresso machine will require a higher quality grinder. Espresso calls for a finer grind size than most brewing methods, so for best results you will want a grinder that has a high degree of consistency. A more uniform particle size will saturate the puck evenly and prevent channeling. In this case, a burr grinder is best. A top-class espresso machine won’t pull amazing shots if the grinder is lower quality and the grind is imperfect. Burr grinders will be best for the consistent grind espresso needs. Beyond that, burr size and material, motor power and RPM, doser or doserless, and other factors should be considered for your needs.
Tamping is integral to making fine espresso and your next step. The purpose of tamping your grounds in the portafilter is to create a uniform surface through which brew water can flow evenly. When your grounds are in the portafilter basket, lightly shake the portafilter from side-to-side to evenly distribute the grounds, and level off by brushing your finger across the surface. When tamping, you want to apply a strong but measured amount of pressure to the grounds on a level surface for an even tamp. A good starting point would be about 30 lbs of pressure.
Be sure not to overtamp or exert too much pressure on the puck of coffee or you can cause channeling. Channeling causes a channel or fracture to open in the puck through which all of your brew water will try to flow, making for a very uneven or poor extraction. Ideally, you also want your tamped grounds to be level so that water flows evenly throughout the puck. If tamped unevenly, water will flow to one side of the puck, resulting in an uneven extraction.
The amount of pressure applied when tamping is a matter of some debate, but it is generally agreed that it's most important to be consistent. You want to apply the same, or similar pressure when tamping every time so that when you need to make adjustments, you only need to pay attention to grind size.
Once you've tamped down your coffee, it's time to lock in the portafilter into the brew head. Once you've done so, begin brewing! You want to aim for about 25 seconds a brew time for your shot, as outlined by the Golden Rule below.
A reliable method for judging your extraction times is by following the “Golden Rule” which states that a double shot of espresso should result in about 2-2.5 fluid oz and take about 20-25 seconds to extract. Keeping this in mind gives you a good measure for what kind of adjustments can be made to grind size and tamping pressure. If your extraction is too fast, you would want a finer grind size. Too slow, and a coarser grind size would be best. Make sure the only variable you have is the grind size; keep the dose and tamp pressure consistent.
The Specialty Coffee Association states that the ideal brewing temperature ranges between 195 to 205, which should result in a shot that is around 160-165 degrees in the cup. Your drink should be hot to the touch, but it shouldn’t scald you.
For Heat Exchangers, you’ll want to perform a cooling flush if the machine has been on but not brewing for some time. You can do this by running brew water out of the group head for a few seconds to remove any overheated water from the system. Other prosumer equipment, especially those with PIDs or Dual Boilers, should have stable temperatures as long as the machine has fully heated up.
Be sure to leave the portafilter locked in while the machines heats to make sure no heat is lost while brewing. Remember to pre-heat your cups with steam or hot water before pulling your shot to maintain a hot cup of java.
The big choice. There’s a multitude of features and finishing touches to any given machine, but the simplest way to approach deciding which machine to purchase is to first consider the boiler type. You’ll find single boilers, heat exchangers, and dual boilers.