Note: The following does not fully apply to super automatic, Hand lever, or steam power-generated espresso machines that "may" operate under different principles and guidelines for proper operation.

Part II: The "Science"

In this section, we will cover the following areas that pertain to the "Science" for reaching "Espresso Nirvana."

• The Fresh Roast of The Coffee Bean
• The Fineness of The Coffee Grind
• The Dosage
• The Tamp Pressure
• The Brewing Temperature
• The Brewing Pressure
• The Fresh Roast Of The Coffee Bean

The most important ingredient to any espresso, cappuccino, or latte is the coffee bean and its degree of roast. As you are well aware, there are many different types of coffee beans originating from many different countries with roast masters applying their own degree of roasting techniques and roast times. Coffee beans from a single coffee farm can be known as "estate coffees." coffee beans from a single country origin are known as varietals. Blending, as preferred by roast masters, is the mixture of 2 or more "estate coffees" and/or varietals to produce their own signature coffee blend. Each "estate coffee," varietal, and blend would change in flavor characteristics when the degree of roast changes. Just as wine changes flavor with age, coffee beans change in flavor with different roasting times.

According to roasting professionals, there are four (4) different types of roasts that are suitable for proper espresso extraction. In order of increasing darkness of roast, they are full city roast, vienna roast, espresso roasted, and french roasted. The main reason to utilize coffee beans with these roasts is that the flavor and crema production of your espresso is highly dependent upon the oils formulated within the coffee beans during and after the roast. Any roast lighter than full city roast may not properly caramelize the coffee beans to produce enough oils for your espresso. As the roasts become darker, the oils tend to move to the surface of the coffee beans as you would see a "glossy" surface or see/feel the oils on them.

Another important factor in the roasted bean is freshness. Freshly roasted beans will provide superior tastes and aromatics. Stale beans or those laying around for a while will not allow you to achieve the fundamentals for "Espresso Nirvana" no matter how much you master them.

Ultimately, it is important to experiment with different coffee beans ("estate coffees," varietals, and blends) with varying degree of roasts to find the best one that suits your palette! Most importantly, it is best to use coffee beans within 7 days of the roasting date!

The Fineness of The Coffee Grind

One of the most important parameters to proper espresso extraction is your coffee grind.

Fineness Of The Coffee Grind
The most important aspect of grind fineness is the ability to grind very very fine (like NutraSweet), AND consistency. The consistency of the grind is directly attributable to the design and performance of your grinder. There are three types of grinders: hand grinders, blade grinders, and burr grinders.

Hand Grinders
Some, not all, hand grinders can grind fine enough and consistently for espresso extraction. The process of hand grinding involves the laborious task of turning the grinding handle many times. The advantage is that this slow process of grinding does NOT produce any heat that would negatively affect your coffee grind.

Blade Grinders
Blade grinders are identified by a whirling blade that "chops" the coffee beans. Grinding long enough, the coffee beans will result into a coarse grind more suitable for drip coffee. Grinding even longer, the coffee beans sometimes can turn slightly finer. However, the finer grind is not suitable for proper espresso extraction. The reasons are:

1. The coffee grind will not be consistent, and
2. The high-speed blade will create excess heat which will adversely affect the oils in the grind of the coffee bean.

Burr Grinders
Burr grinders typically consist of 2 opposing grinding burrs - 1 stationary and 1 attached to the motor wheel. There are 2 types of burrs - conical and flat. Conical burrs are designed to produce greater consistency in the grind fineness. However, the type of burr becomes irrelevant as one chooses a high quality "flat" burr grinder that typically houses larger burrs closer to the commercial type.

Burr grinders typically have the advantage of lower heat generation due to the lower speed of the burrs. In addition, different degrees of fineness are achieved by changing the setting which changes the distance between the grinding burrs. The greater the distance between the grinding burrs, the coarser he grind. Oppositely true, the lesser the distance between the grinding burrs, the finer the grind. The equidistance of the grinding burrs achieves the consistency needed for proper extraction of your espresso.

The settings on burr grinders will differ from customer to customer. First, all electric burr grinders have relative settings. This means that a setting of "6" on one particular grinder will not be "precisely" the same as a setting of "6" on another unit of the same model grinder.

Second, each type of coffee and the darkness of roast will and may require different settings to adhere to the fundamental rule. In the former instance, beans from two different farms, countries, or blends will have differences in the grind fineness from one to the other in acquiring the fundamental rule. The reason is that different beans have varying degrees of hardness. In the latter instance, A darker roast will require a courser grind when compared to a medium roast to achieve similar extraction times and volume (however, the taste will be different). Lighter roasted espresso beans should be ground finer than darker roasts. The main reason a finer grind is required on lighter roasts is that lighter roasted coffees do not have the coffee oils on the bean surface. Therefore, a finer grind is needed to expose those oils on a greater surface area that results from a finer grind. Darker roasted coffees tend to have oils at the surface.

Therefore, experimentation (not frustration) is essential in locating the best setting for your coffee beans.

Finally, burr grinders should always be adjusted when the grinding burrs are in motion. This is especially important when adjusting from a coarse setting to a finer setting. The reason is that coffee grinds will always be between the two burrs, and this ground coffee will not allow you to properly adjust the grinder to a finer setting. The end result is a more consistent grind and less chance of the burrs becoming dulled or gummed.

The Dosage

The amount of coffee (known as the dosage) you place into the filter basket (on traditional filter handle machines) will also affect the "Fundamental Rule". The industry standard in the United States is 7 grams of coffee roasted and ground for the single espresso shot and 14 grams of coffee roasted and ground for the double espresso shot. This standard is an industry guideline. This means that the guideline can be adapted and changed to one's personal need to achieve the crema rule and taste profile desired.

Typically, adding an amount greater than 7 grams of coffee will result in a longer extraction time since the "extra" coffee will increase the path the water needs to travel - this creates greater resistance. Less than 7 grams would result in a quicker extraction time since there will be less coffee to create the resistance needed for a proper extraction.

The Tamp Pressure

Tamping is essential to proper espresso extraction. Proper tamping would result in creating enough resistance for the water to pass through the coffee grind, in creating even distribution of resistance, and in easy removal of the ground coffee from the basket after extraction.

Tamping is the application of applying force to compact the loose coffee grind in your filter basket into a "puck." A special tool known as the "tamper" is utilized to tamp the coffee. For some machines, the tamper is built into the machine, while in others, the back of the measuring spoon is utilized as the tamper.

The tamper consists of a tamping plate (which is made from either plastic, wood, aluminum, or stainless steel), A stem, and a handle. there are 2 types of tampers - flat or curved. Flat tampers are typically utilized when the filter basket is straight edged on the bottom of the basket and curved tampers are utilized when the filter basket has a curved edge on the bottom.

In the market today, there are two types of home model espresso machines that impact the technique needed to acquire proper tamping pressure. The first type are home model espresso machines that have PRESSURIZED handles or filter baskets. Please note that either the basket OR the handle are pressurized, but not both on any machine. This type of machine design compensates for "tamping error" by allowing the design of the filter handle or filter basket to create the required pressure needed for a proper extraction of espresso. Machines of this type include the Capresso line, the Solis Crema SL line, and the Saeco line. Other machines, such as Gaggia, sometimes include pressurized disks that serve the same purpose. The second type are machines that have standard, non-pressurized filter handles or baskets. All traditional, commercial machines, as well as many home models, are of this type. Tamping pressure is much more critical on these machines since the resistance to create a proper extraction relies more on the tamping pressure and fineness of grind due to the fact that the "pressurized handle or basket" is non-existent to create the pressure. Here are the different techniques for each type of espresso and cappuccino machine.

General Technique For PRESSURIZED Filter Handles and Baskets - The general technique for tamping in a pressurized filter handle or pressurized filter basket would be less than 30 pounds. In other words, only a very light tamp is needed. The proper tamp can be accomplished with the hand tamper, with the tamper built into the espresso machine or grinder, or with the back of the measuring spoon. Please note that too firm of a tamp will not allow the water to come through the coffee grind or will result in a very long extraction time (usually exceeding 27 seconds)

General Technique For STANDARD Filter Handles and Baskets - The general technique for tamping in a standard filter handle is to apply about 30-50 pounds of evenly distributed pressure into the coffee ground dosed into the filter basket. The technique should be completed with a slight twist to result in a slightly polished finish on the surface of the tamped coffee. The 30 pounds of tamp pressure is a guideline and an area for experimentation as some of our customers have used less tamping pressure and others have tamped to 50 pounds of pressure. Some 1st-Cup Coffee Company customers have used a bathroom scale to measure tamp pressure. By using a scale to measure pressure, you can change one of the other parameters to achieve the fundamental rule.

The Brewing Temperature

The optimal brewing temperature, as measured at the point where the water contacts the coffee grind, is 190-204 degrees Fahrenheit. The temperature of the extracted espresso will vary from 150 degrees Fahrenheit to 180 degrees Fahrenheit. The temperature loss is attributable to the ambient temperature, the brew group temperature, and the temperature of the cup.

Therefore, it is important to preheat the brew group and the cup prior to extracting espresso. The brew group can be pre-heated by pulling an "empty shot." In other words, the filter handle and basket should be placed on the brew group (or group head) without any coffee and hot water from the machine should be run through and into the cup that needs to be pre-heated. We have found a temperature loss of up to 100 degrees Fahrenheit in circumstances where customers do not preheat the brew group, The filter handle, the filter basket, or the cup. Also, do not make the mistake of rinsing your filter handle and filter baskets with cold or hot faucet water. This can also reduce the temperature. It is best to wipe the handle and basket clean with a cloth or paper towel.

In addition, the closer the spouts of the filter handle to the base of the cup, the less the temperature loss due to room temperature.

The Brewing Pressure

The optimal brewing pressure for pump-driven espresso machine is 8 to 9 bar or atmospheres. Most machines show pressure "ratings" of greater than 9 bar. Please note that these "ratings" indicate the "maximum" pressure that can be produced by the pump. It does not mean better espresso! Quite the contrary! Over 9 bar pressure can produce very BITTER tasting espresso.

Since most home model machines do NOT have gauges to monitor the brewing pressure, you may wonder how you know if we are at the optimal pressure. The answer is very simple. We will know if we are at the right pressure by comparing our results to the fundamental rule -double espresso shot = 2 to 3.0 fluid ounces in 23 to 27 seconds.

The pump pressure is regulated by the resistance in the filter basket - the resistance of the espresso bean finely ground and tampered into the filter basket or the resistance created by the pressurized filter handle or basket.

A greater resistance in the filter basket will result in a greater pressure created by the pump. Too much pressure, the espresso will take longer than 27 seconds to extract. This is called over extraction and will result in a very bitter flavor. In addition, the home model espresso machines we sell have an expansion relief valve - when there is too much pressure (that over 11-12 bar), this expansion relief valve will open to relieve the excess water pressure and divert it to either the machine's drip tray or back to the water tank. The purposes are to avoid pump damage and lessen the chances of over extraction.

A lesser resistance in the filter basket will result in a lesser pressure created by the pump. Too little pressure, the espresso will take less than 23 Seconds to extract. This is called under extraction and will result ina a very weak, water down coffee. In this case, the resistance in the coffee puck needs to be increased by changing one of the above variables - coffee grind fineness, amount of coffee grind, or tamping pressure. By grinding finer, increasing the amount of coffee grind, AND/OR increasing the tamping pressure, the resistance will become greater to extract at the right pressure.

Therefore, the resultant brewing pressure is a direct result of the resistance in the filter basket. Now, that we have covered the Science, we should morph your knowledge into the Arte!