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Key Ingredients In Perfect Espresso

Posted By: Aabree Coffee
Posted At: Nov 28, 2011 at 10:53 AM
Related Categories: Espresso Essentials

Making coffee is a lot like baking a cake. There are specific ingredients and parameters that are required in order for the creation to be considered cake, but the requirements for making a Tunnel of Fudge cake are a lot different than making a Carrot Cake. The same goes for coffee – basically anything that involves combining coffee grounds with hot water is considered coffee, but there are specific requirements for making the espresso type of coffee. In this article, we’re going to take an in depth look at these key ingredients and parameters, and how to put them all together to make a proper espresso.

Temperature

Espresso is brewed using water that has been heated to between 190o F and 195o F. A thermostat in the boiler brings the temperature of the water to the proper level and maintains it while the machine is on. As you begin to brew, the thermostat will turn on again in an effort to heat the water that is being drawn in from the reservoir as the already heated water is used for brewing.

Although espresso is brewed with water temperatures exceeding 190 degrees F, it doesn’t necessarily mean the temperature of your espresso will be that hot when you go to enjoy it. Generally, the temperature can be quite less, with an average 160 degrees F to 165 degrees F in your cup. The large drop in temperature is largely contributable to whether or not your portafilter, brew group, and espresso cup have been fully pre-heated. We always recommend pulling a “blank shot” to remedy this problem. Before brewing, just attach the empty portafilter to the machine, place your cup under the portafilter, and press the brew button. Hot water will be dispensed through the portafilter and brew group and fall into the cup, thereby heating all three elements at once. Proper temperature is also a large contributor to the quality of the crema that tops your espresso. Crema dramatically impacts the flavor of the shot, making temperature even more important to the overall success of your espresso.


Pressure

When we’re talking about pressure in relation to espresso, there are actually two different things we need to address: tamp pressure and brewing pressure.

Tamp Pressure
This is the amount of pressure used to compact the coffee grounds in the portafilter prior to brewing. As a general rule, we recommend consistently using 30 lbs of tamp pressure. If you’re not sure what that feels like, drag out the ol’ bathroom scale and try it out – it won’t feel nearly as heavy as you’re expecting. By always using the same amount of pressure, you’re reducing the number of variables involved in brewing, so it’s easier to target and resolve an issue. We’ll talk more about possible problems you’ll run into and how to solve them later in this article.

Brewing Pressure
In order to brew a proper espresso, hot water must be forced through the coffee grounds at around 8 or 9 BAR of pressure – roughly 135 PSI. The pump inside every espresso machine is designed to produce these exact measurements of pressure, so this isn’t something you’ll need to control yourself. Some machines advertise they are able to produce pump pressures of 15 to 19 BAR. However, this doesn’t mean that they will they produce better espresso than those of lower pressures. As described above, it is only necessary to have about 8 to 9 BAR of pump pressure to produce good espresso. The pressure ratings on these units pertain to the maximum pressure or BAR the espresso machine is able to produce, not what it will actually brew the espresso at. Just remember that it isn't important to buy an espresso machine with the most powerful pump. Any pump driven espresso machines we carry provides more than enough pressure to produce fine espresso.

Coffee, Water, & Extraction Time

So we’ve talked about temperature and pressure and set the stage (or greased the cake pan, if you will) for the down and dirty “this is how you do it” part of brewing espresso. Yes temperature and pressure are equally as important to espresso as the things we’re about to discuss, but they’re a little more abstract to you budding baristas out there. This is the part you actually get to put your hands on and find out what brewing espresso is all about.

Most commonly, espresso is brewed as either a single or double shot. This terminology references the amount of coffee and water that are used. To brew a single shot, you will use 7 grams of coffee and pull between 1 and 1.5 oz of water. For a double shot, you’ll basically double those quantities – 14 grams of coffee and 2 to 2.5 oz of water. No matter if you’re brewing a single or double shot, you should be able to extract the espresso in 20 to 25 seconds.

This little equation is what we call the Espresso Rule of Thumb, and it acts as a guideline for brewing espresso. If the results you’re getting don’t meet these parameters (for instance, you get 3.5 oz of espresso in 20 seconds), you’ll know instantly that something isn’t right and that you need to alter one of your variables to meet this target. We’ll look at some specific scenarios and how to correct them in a minute, but let’s look at the Espresso Rule of Thumb one more time.


The Espresso Rule of Thumb

Given that water between 190 degrees F and 195 degrees F is applied at 8 – 9 BAR to finely ground coffee that has been tamped at 30 lbs of pressure:

A single shot is made with 7 grams of coffee, and should yield 1 – 1.5 oz of espresso in 20 –25 seconds.

A double shot
is made with 14 grams of coffee, and should yield 2 – 2.5 oz of espresso in 20 –25 seconds.

Troubleshooting


The next question out of most people’s mouths is, “What do I do if my shots don’t meet these requirements specifically?” Well, the good news is that because you’re keeping the amount of coffee and tamp pressure the same in each attempt, there’s only one thing to alter in order to get different results: the fineness of your grind. This is one of the main reasons why a grinder is such an essential element to brewing espresso and why we always recommend that you purchase one to accompany your semi-automatic machine. Beyond the obvious advantages of the freshest coffee possible, using your own grinder makes it much easier to troubleshoot a problem if one arises.

The two main problems people run into are that their shots are either too slow or too fast. If your shot is slow (it takes longer than 25 seconds to brew the correct amount of espresso), it means that the water is being prevented from coming through the grounds at the appropriate rate. You can fix this by adjusting your grinder to a coarser setting. On the other hand, if your shot is fast (it takes less than 20 seconds to brew the correct amount of espresso), it means that water is passing too easily through the grounds. This is remedied by adjusting your grinder to a finer setting. Every time you adjust your setting, just remember to keep your tamping consistent and time your shot to make sure you’re on target.

We know that not everyone can spring for the semi auto and matching grinder right away, so some of you may be using pre-ground coffees. The Espresso Rule of Thumb still applies here, but if you’re not hitting your target extraction times, you’ll want to alter your tamp pressure to compensate. Tamp harder if your shot times are too fast, and lighter if your shot times are too slow. If you’re getting similar results regardless of the tamp pressure, it may simply be that the grind setting will not work well with your machine.


Other Things to Keep In Mind

Although the Espresso Rule of Thumb does apply to all semi automatic espresso machines, the strict parameters we’ve set are a little different depending on what type of semi auto you’re using. Those machines that have commercial style portafilters are a bit more sensitive to these guidelines, so you’ll want to keep with them specifically. However, pressurized style portafilters are more forgiving when it comes to tamp pressure and grind setting. You’ll want to aim for a lighter tamp as well as a slightly coarser grind if you’re using a pressurized portafilter, but the other requirements will remain the same.

It is also important to remember that you may need to make adjustments to your grind setting when you try a new type of coffee. Beans can differ in roast level and density, both of which can affect how the grounds perform. So, it may be necessary that you “dial in” your grinder again if you notice that changing beans affects your brewing time.

If you ever have any brewing issues that you just can’t seem to solve using the troubleshooting tips we’ve given you here, please feel free to call our Customer Care Center at 888-280-8584. We’ll give you any further advice we can and get you on the path to perfect espresso.
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