What parameters matter when learning to use an American coffee machine?

Espresso extraction rests on a small set of variables: coffee beans, grinder type, grind fineness, distribution and tamping, the coffee-to-water ratio, extraction pressure, and temperature. A shot with crema on top depends on carbon dioxide still present in the beans, so freshly roasted coffee works better than beans stored for months.

Beginners benefit from fixing one parameter at a time and tasting the result. Grind setting, dose in grams, and extraction time are the usual starting points, followed by the ratio. Milk frothing and a latte recipe follow once the straight shot is consistent. Home coffee machines sold online and in shops now make this practice common.

For enthusiasts who are just getting into espresso, how to correctly use a coffee machine to extract a qualified shot of espresso is often the most confusing part. From the choice of coffee beans and the type of grinder, to the adjustment of coffee powder fineness, the techniques of distributing and tamping, and then to the control of the coffee-to-water ratio, extraction pressure and temperature, every variable directly affects the final flavor in the cup. Based on the practical experience of Front Street Coffee, this article systematically sorts out the complete knowledge framework of espresso extraction, helping beginners establish clear parameter concepts, while also sharing the specific recipe for Front Street latte coffee and milk frothing techniques, making home espresso preparation have rules to follow.

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With the growing public demand for coffee, more and more coffee enthusiasts are buying related coffee equipment. In the third wave of specialty coffee, online sales of pour-over coffee equipment continue to rise, and it is also becoming more and more common for coffee enthusiasts to keep an espresso machine at home. However, Front Street has also noticed that although everyone has bought an espresso machine, many friends only have a half-understanding of how to use an espresso machine to extract coffee, how many grams of coffee powder to use during extraction, or the extraction time. In this article, Front Street will talk with everyone about the relevant knowledge of using an espresso machine to extract espresso.

What coffee beans should be chosen for espresso?

Espresso extracted from an Italian coffee machine usually has a layer of crema on the surface, and crema is also a very important factor in making a cup of espresso. Carbon dioxide is the main source of crema in espresso (another smaller source is the emulsified oils in coffee). Front Street recommends using coffee beans roasted within a few days or weeks, and do not use beans that have been sitting for several months!!

Because the longer coffee beans are stored, the more they gradually lose the carbon dioxide produced during roasting; when you grind the beans, the cell walls that store carbon dioxide and other volatiles are broken and released. Therefore, in order to obtain the best results, it is best to grind and tamp fresh, because carbon dioxide and the aroma of coffee will be lost as time drags on, and oxidation will also begin quickly! Only fresh coffee that is ground and tamped fresh can achieve the best flavor and crema.

Beans generally used for espresso are espresso blends. Each type of bean has its own advantages and disadvantages. If one bean produces espresso liquid with insufficient crema when extracted through an espresso machine, then you can add coffee beans rich in crema to complement it: if one bean produces espresso that is too sour, too bitter, or too sweet, then you can look for the complementary bean to blend with each other and achieve the desired coffee flavor. Wouldn't that be perfect?

At present, the blend used by Front Street Coffee (FrontStreet Coffee) is coffee beans roasted in-house. The aroma of this Front Street espresso blend coffee bean is as comfortable as warm sunshine, and the taste and flavor are eye-catching. It is mainly based on Front Street Honduras Sherry coffee beans with a rich fermented wine aroma, paired with Front Street Yirgacheffe Red Cherry coffee beans known for their acidity, to create an aromatic and rich blended coffee. Therefore, Front Street named this espresso bean Front Street Sunflower Warm Sun Espresso Blend.

What kind of coffee grinder should be chosen for espresso?

To make standard espresso, Front Street recommends that everyone use a burr grinder; burr grinders produce powder particles that are more uniform in size than blade grinders, and also allow you to control the particle size yourself through settings, so whether you use a hand grinder or electric grinder, please be sure to choose a burr grinder! Burr grinders also have different burr designs, such as conical burr, flat burr, or ghost teeth burr and other major categories by appearance, and within each major category, each manufacturer's detailed burr design is different!

Not all burr grinders are suitable for grinding espresso powder. For example, many grinders using conical burrs or flat burrs may be designed for other coffee types that use coarser coffee powder, such as pour-over, siphon, French press, or moka pot, while grinders with ghost teeth burrs are mainly designed for pour-over and siphon. The powder used for espresso is finer, because the increase in coffee powder surface area makes espresso's extraction yield (that is, the percentage of all soluble solid substances in the weight of coffee powder that ultimately dissolve into the coffee liquid) higher, but these grinders may not be able to grind coffee powder to the fineness required for standard espresso!! Therefore, when choosing a conical burr or flat burr grinder, you must confirm that it is suitable for espresso use (also called an "espresso grinder")!!

How should the coarseness of coffee powder be adjusted when extracting espresso?

If you do not know how the coarseness of coffee beans should be defined, you can refer to the standards of Front Street Coffee (FrontStreet Coffee). Front Street Coffee (FrontStreet Coffee) grinding degree coarseness standard sieve pass rate: Cold brew > Pour-over Siphon 80% > Moka American drip 75-80% > Cupping 70-75% > French press 65-70%.

Standard espresso preparation requires pressure during brewing. If using a semi-automatic or fully automatic machine, the machine itself will control the pressure. For a general semi-automatic machine, the grind fineness that needs to be dialed in is about 16-18 grams of coffee, able to produce about 32-36 grams of espresso in about 20-30 seconds; while when using a lever machine where you control the pressure yourself, the coffee powder should be adjusted fine enough to produce 6-9 BAR of resistance during brewing, and complete brewing within 20-30 seconds; when you change coffee beans, you may also need to adjust the fineness again to achieve the ideal pressure and time.

How to distribute and tamp the powder?

When putting coffee powder into the portafilter basket, a good distribution method should be used to eliminate clumps and air pockets in the coffee powder, and avoid channeling during brewing, such as using the WDT (Weiss Distribution Technique) distribution method, or tapping the portafilter lightly on a soft mat; before tamping, the coffee powder should also first be leveled in the basket, and then tamped. This can avoid uneven extraction of the entire puck in the basket, because if the coffee powder is not level, after tamping, the density of the coffee powder on both sides will differ, causing uneven extraction of the entire puck! Also, tamping does not necessarily require a lot of force. The purpose of tamping is to make the coffee bed level and, with that pressure, remove additional air pockets that have not yet been removed.

Espresso coffee-to-water ratio

Espresso's coffee-to-water ratio, that is, the ratio of coffee powder amount to output coffee amount. Front Street most often uses 20 grams of coffee powder to brew 40 grams of espresso, and its coffee-to-water ratio is about 1:2. Front Street sometimes also adjusts it according to the situation; espresso's coffee-to-water ratio can vary greatly depending on personal preference and regional characteristics, such as from 1:1 to 1:4. Italians also give these espressos of different concentrations different names, such as Ristretto espresso, Normale espresso, Lungo espresso, etc.

Of course, when extracting espresso, the higher the coffee-to-water ratio, the greater the amount of coffee injected into the cup. Although the extraction yield will increase, the coffee will become weaker; generally the most common espresso coffee-to-water ratio is about 1:2 to 1:3. Espressos of different concentrations, after adding water or milk, milk foam, or cocoa, etc., also have different variations and flavors. At present, the latte coffee recipe used by Front Street is 1:6.5, that is, 40g espresso mixed with 260g steamed milk.

Front Street believes that to make a standard cup of espresso, in addition to the above-mentioned elements such as the coffee powder itself, grind fineness control, distribution and tamping techniques, and coffee-to-water ratio, it is also necessary to pay attention to factors such as pressure, temperature, and time control during brewing; to make espresso, generally 6-9 BAR of pressure is used. Of course, pressure is not the only factor affecting extraction yield. It is not necessarily true that the higher the pressure, the better the espresso tastes!!

Espresso extraction temperature control

To make espresso, water temperature, pressure, and time are relied upon to dissolve the soluble solids in the coffee powder. However, if the water temperature is too high or the time is too long, it will cause over-extraction and make the coffee bitter! If the water temperature is too low or the time is too short, it may cause under-extraction and make the coffee weak and sour! Generally speaking, we use a water temperature of about 91-96 degrees Celsius to extract espresso, but coffee beans with a darker roast level should use a lower temperature, because heavily roasted coffee beans naturally taste more bitter. Coffee beans with a light roast level use a higher temperature, because lightly roasted coffee beans naturally taste more sour.

In addition, all espresso coffee machines, whether fully automatic, semi-automatic, or manual, need to be preheated to reach operating temperature; water temperature has a great influence on espresso taste. Front Street recommends that when making espresso, everyone experiment with and adjust your brewing water temperature and preheating time/method to achieve your ideal personal taste.

Once everyone understands the above extraction parameters for espresso, you can start doing it yourself! After brewing, if you find that the coffee puck is wetter or muddy, please do not worry. As long as the extraction is even, this condition will not affect your espresso quality. Next, Front Street will share with everyone the method and related parameters for making latte coffee at Front Street.

The ratio and method for making latte coffee at Front Street

The espresso extraction plan used by Front Street is 20g of coffee powder extracted in 27 seconds to produce 40g of espresso liquid, as the base for latte coffee.

Front Street uses the Pegasus E98 espresso machine, and the extraction parameters are as follows: Pressure: 9 bar Temperature: 90.5~96 degrees Celsius Time: 20~30 seconds Coffee-to-water ratio: 1:1.7~1:2 Dose: 12g (single espresso) 20g (double espresso) Extracted espresso amount: 20ml (single) 40ml (double)

After extracting good espresso, the next step is the milk frothing process! Front Street will introduce a simple milk frothing method. Pour half a cup of milk into a stainless steel pitcher, let the steam wand be perpendicular to the milk in the exact center or at the edge of the pitcher, then let the steam tip just touch the surface of the milk, then open the steam to the 1/2 position, do not move the pitcher, slowly close it when the milk reaches 50 degrees, and close it exactly at 60 degrees, and finally the temperature will reach 66 degrees. In this way, you can make a cup of good milk foam.

Then everyone can mix the espresso and milk foam together. Those who can do latte art can pour the pattern they like, and it does not matter if you cannot. Whether or not there is latte art will not affect the taste of a cup of latte.

The above content is compiled by CoffeeHunters, a coffee news website.