Brewing Temperature:
This is controlled by your machine’s thermostat. Our tests have shown that the machines we sell all fall within the proper temperature range of approximately 190 to 196 degrees so you do not have to consider this parameter when selecting a machine. Generally, you do not have to be concerned about this when you are operating the machine except under certain circumstances. I do not want to confuse you too much at this time, but as long as you watch your "ready lights" you will be just fine.  The "in cup" temperature should be around 160 to 165 degrees. The heat loss seems substantial, but it is attributable to the brew group, the air and the cup. This temperature will feel hot to the lips but not scalding.
To ensure that you get the proper "in cup" temperature you should preheat the cup as well as the brew group. The cup can be heated several ways - cup warmer on the espresso machine, hot water from the espresso machine or even hot water from your faucet.
The brew group for this discussion includes the portafilter handle (what you put the coffee into) and the part of the machine that you lock it into. This can be preheated by letting the machine warm up for 5 to 6 minutes. However, I suggest that you run 2 ounces of water through the group with the handle in place (without coffee) and into the cup. I call this shooting a blank. It is the most efficient method and the second shot is always better than the first anyway! Brew Pressure:
This is the amount of pressure developed when extracting the coffee. We look at approximately 8 to 9 bars or atmospheres as being the optimum environment. You may have noticed that the home machines show pressure ratings of 15 to 19 bars. This is purely an indication of the maximum pressure the pump is capable of producing. More pressure does not mean better coffee!
Now let me ask a couple of questions for you.
"OK, so how do I know when I am at the right pressure, is there a gauge to tell me?"
Well, no. There is no gauge, but we "infer" we are at the right pressure based on the golden rule. This may begin to sound complicated, but we really do not have to worry about the pump’s pressure. The machines are designed to not allow any more than 8 to 11 bars, if the pressure begins to exceed that level then a special valve (back pressure relief valve) opens and diverts the water to either the water reservoir or the drip tray. This serves at least 3 functions: it protects the pump from excessive pressure buildup, lessens the likelihood that the coffee will be over-extracted and prevents the machine from blowing coffee all over the counter top! "If the machine ensures that the proper pressure is obtained, why do I care to bother with this at all?"
The machine does not ensure the right pressure, it only ensures that you do not use too much. You still have to avoid too little pressure. This occurs when insufficient resistance exists in the brew group. You create resistance through the Science of Tamp Pressure and Coffee Grind. We will get more detailed in latter commentary, but simply put - the greater the tamp pressure and the finer the coffee grind the greater the resistance. Too little resistance does not allow for sufficient pressure and the resulting beverage is weak with little crema. We call this underextracted coffee. Too much resistance will cause an overextraction; bitter and little crema as well. Tamp Pressure:
 This is the amount of force that you apply to compact the coffee grounds that you have placed in the filter handle. You use a "tamper" that is supplied with most machines. It is a round flat tool with a short gripping handle that is used to press down on the coffee. It is made out of plastic, wood, aluminum or stainless steel. The general technique for tamping is to apply about 30 pounds of level pressure finishing with a twist to polish the top of the exposed coffee grounds. You can use a bathroom scale to get a good sense of what 30 pounds of pressure feels like. If you place the portafilter handle on a counter top and lean into it with the tamper you will have greater control.
Now, I say general technique because some machines require only a light tamp. Those machines are designed with "pressurized filter handles". They are designed with built-in resistance technology. These systems work very well, but still require that you understand the principles of tamping pressure and are available on machines made by Saeco, Capresso and Solis. Machines made by Gaggia, Rancilio, La Pavoni (piston style) and Francis require the user to create the resistance without such aids. They are designed for the user to have control of the tamping which will provide more of the art influence. Latter in this discussion I will illustrate the usefulness that this ability can provide. Beans:
Obviously, this is the key ingredient to any espresso, cappuccino or latte. You probably have noticed that there are seemingly endless varieties available. It is appropriate to think of this vast variety as wine - they all have their own nuances that play differently on each pallet and evoke one’s own sense of "ahh Javaaaa". So, ultimately it is important to seek out those roasts that will take you to Java Heaven. However, to get there you need to understand the differences between the roasts because preparing them properly will make the difference between rejection and elation.
 If we simplify coffee roasting to 3 main styles it will be simpler to convey the proper extraction methodology. Light, medium and dark roasts. This is simple to understand because they are also visual clues such a light, medium or dark brown. Certainly there are roasts that may fall somewhere in between, but the process for extracting them will also follow right along.
The light roasts are not, in my opinion, suitable for espresso so we only have to concern ourselves with the medium or dark roasts. Most people relate to the dark roast as a true espresso roast but this is not actually correct. Illy, one of the foremost renowned Italian roasters in the world produces a superb medium roast. The dark roast will distinguish itself with an oily surface, you can tell because of a high gloss surface and they may have a tendency to stick together.
Preparing these roasts will require slightly different techniques that speak to the art of making espresso. However, it is actually quite easy to adjust for the differences. It is as simple as this. A dark roast will require a coarser grind than a medium roast for the same extraction. This is not to mean the same flavor, but the same adherence to the golden rule; double shot = 2 to 2.5 ounces in 20 to 25 seconds.
"That was easy, so what is the big deal?" Huge actually if you don’t follow the golden rule. Too fine of a grind can cause several problems. It can gum up and prematurely wear out the grinder burrs, clog the dispersion screen on the espresso machine & filter basket, and worst of all, make a bitter cup of coffee from a great bean - overextraction. "So how do I know when I have the right grind? " Simple, once again simply follow the golden rule. If you get those results, then you are getting the best of the bean. For instance; if you are experiencing a long extraction time of 40 seconds, it will be colder than normal, have thin crema, be dark and probably bitter. Some people mistake this for a weak pump on the espresso machine. This is not the case, remember the machines have a backpressure relief valve that prevent excessive pressure build up much beyond 10 bars or atmospheres. Believe me, you would not want more pressure. The coffee would be extremely over extracted and make it more difficult to "dial in" the machine. The Grinder:
There are two types of grinders - burr and blade. The nasty looking blade that whirls around with blinding speed easily identifies the blade grinder. Burr grinders do not have visible grinding wheels except if you were to remove the bean hopper. For espresso making stay far away from blade grinders. They cause a number of problems such as dust, heat and inconsistent grind fineness. Attaining the golden rule on a consistent basis will be all but impossible with a blade grinder. However bad coffee will be very consistent!
 The burr grinder has two opposing grinding wheels. It is the distance between them that determines the size of the grind. The coffee bean is ground until it can drop through between the burrs and into a receptacle - usually a doser or a basket. The grinding is usually slower than a blade grinder which introduces less heat and static electricity to the coffee. Heat reduction is important because it preserves more of the coffee flavor. Static electricity will cause the ground coffee to repel itself and fly out of the coffee container - as if coffee wasn’t messy enough! Burr grinders can also exhibit this behavior but to a lesser degree. There are two types of burr grinders - Conical and flat burr. There is really not a big difference between them that would rate one as better than the other, particularly with home grinding. When you are calibrating a grinder you will usually find that the best espresso grind setting will be in a range of 3 to 8 on the grinders index. The lower the number the finer the grind - this is universal for all grinders. But do remember, a finesse setting on one grinder will not necessarily match the finesse on other grinders. This is only a relative position which simply means that a setting of 5 is coarser than 4 but finer than 6.
The important aspect here though is the consistency of the grind. In order to reproduce excellent coffee time after time the grind fineness must be the same. Variation will cause wildly fluctuating extraction times and the coffee quality will suffer accordingly. Special Note: When adjusting your grinder make sure the grinder is running. This is because the grinding burrs need to move closer for a finer grind. Since coffee is actually a very hard material you will stress the adjustment mechanism and can actually damage the machine!
This is where you put it all together. The machine applies the pressure and temperature such that you do not have to think about that too much - at least for now. | 
printer version
Making espresso for your coffee drinks - cappuccinos, lattes, mochas, etc., requires that you understand the process or Ritual, as I call it. The visual clue that tells us that we have achieved Java Heaven is called the "crema". The crema is that golden marbleized foam that covers the top of the espresso. Without waxing poetic which is often done in this business, the crema is simply nirvana. It’s the foundation of the coffee culture that you have joined and the reason why you’re reading and why I’m writing this "Understanding" segment. I know this may sound intimidating, but if you spend a little time learning you will be able to teach those Starbucks kids a thing or two in short order. The reason this is so important is because it is too easy to make a bad cup of coffee. With the proper knowledge you can break the mystique and brew high quality espresso in no time at all. So, grab a cup from that good old Mr. Coffee, sit down and read everything you need to know on brewing better coffee.
Take a look at the tamped coffee. It should be compacted and the surface level. An unleveled surface can cause problems with the extraction varying from uneven pours to bad extractions. The surface should look polished and any loose coffee grounds around the top of the rim need to be brushed off. This is important so that the gasket that creates a water tight seal does not get encrusted with coffee. Should that occur then you might experience leaking around the group and an overall unsanitary and unflavorful condition - rancid coffee!
You will find that there is a world of difference between a 15-second shot and a 20 to 25 second shot. The same can be said for an over 30 second shot. The crema will be at its thickest consistency as well as volume. The coffee will be at its best extraction.