Coffee Cup
"Espresso! My Espresso!"
An Ongoing Internet Novelette
by Randy Glass - Copyright 2007 - All rights reserved

Coffee Cup
The Secret to Espresso...
There is No Secret

      I have been contemplating an article on how to make espresso, encompassing all that I have learned in the last seven years of trials and tribulations encompassed in home roasting and baristaring. By this time you probably have a good idea about the basics, whether or not you have been making espresso at home. The basics involve grinding coffee, filling and tamping the coffee in the basket, lock and load, pull the trigger and count the seconds and ounces. About 25 or 30 of the former, and about 1.5 to 2 of the later. Too many of the first or too few of the second? Grind finer and try again. Too few of the first or too many of the second? Choose a grind that is more coarse.

      Once you have that under control you are making espresso. The problem is that even if you get exactly the correct amount of liquid and it occurs in exactly the correct amount of time, it does not at all assure you that you have made good espresso. I know that to be a fact, and have sampled the evidence to prove it. When you sip and then wince, the problem for the home barista is what to do about it? I have often had folks write me with just that situation asking that very same question. It is not one easily answered and I am going to attempt to address why.

      During the preparation for the pull there are a number of factors that are difficult (if not impossible) to define in concrete terms. Once of the first is to decide how much coffee to use in the basket. The volume is important, but this is difficult to measure accurately because of compression of the grounds when handling (contents may indeed settle during shipping). Some grinders are very prone to clumping which affects the total mass in a volume of coffee, and some grinders create a very fluffy grind (leaving more air between the particles). The only accurate way to quantify how much coffee to use is to weigh the ground coffee which is an indirect measure of volume, but accurate enough for what we need. A gram scale which is capable of weighing in tenths of a gram is necessary.

      To decide exactly how much coffee to use, weigh a dose of coffee. If you are using a standard double basket, try starting with 14 grams. If you weigh the coffee in a separate vessel and your grinder clumps, use a straightened paper clip or dissecting needle to break the coffee up to a more clump-free consistency. Now you need to get the coffee into the basket. Make a funnel from a yogurt cup by cutting off the bottom. You can use the de-clumping device to distribute the coffee as evenly as possible. I know that my Rocky has always created some pretty good clumps, but there are grinders which are virtually clump-free when grinding. If you are fortunate enough to have one of those then it will obviously make all of this a lot easier. You can actually tare out the portafilter on the scale and dispense the coffee directly into the portafilter.

      So right off we see that there is no one rule as to how to get the correct amount of coffee into the portafilter. It might be that your grinder has an adjustable doser and grinds clump-free and distributes the coffee so well that a predetermined number of clicks of the lever and you are done. Your grinder may compress the coffee so much and create so many dense clumps that you will need to go through all the above steps to be successful.

      The next step is to be sure that the coffee is distributed in the portafilter basket as evenly as possible. In a best-case scenario, you will not need to do anything. At the other extreme, you will need to stir the coffee with the distributing needle. I stir in small circles that cross the center of the basket and each circle also touches the outer edge of the basket, circle around the entire basket. It is sort of a “Spirograph” pattern for those old enough to remember that wonderful toy. If the “spiro-stirring” is necessary you may choose to stir with the yogurt funnel still in place to keep the coffee from spilling out of the basket.

      You have dosed, distributed, and so it is now time to tamp. The first factor to consider is the tamper itself. For the diameter, the closest fit possible is best. There has long been discussion of the shape. Convex? Concave? American curve? Flat? The best advice I have read is to pick a tamper that duplicates the shape of your shower screen as closely as possible. Otherwise, choose flat.

      The next discussion is to consider the tamping effort needed. Here we go again... Handstand tamp? Leveling tamp? Always 30 pounds? Newton-meters? In the long term I believe that you are going to find that it doesn't matter as much as you might think. As you start out in this, my advice would be to tamp around 10 to 20 pounds. Experiments have shown that anything over about five pounds and below about fifty pounds will yield about the same results. So why the “calibrated” tampers? Good question, and one I think you will be asking as you refine the procedure outlined in this article.

      After tamping, the penultimate test is to check to see if you used the correct amount of coffee. If you have a “screwless” showerscreen, place a nickel in the center of the coffee. Carefully lock the portafilter into the grouphead and then carefully remove it. Examine the coffee. Are there any marks on it? There should be only the slightest mark on the coffee. The idea is that you want a three to five millimeter gap between the shower screen and the top of the coffee puck before the extraction begins. If that test was successful, lock it back into place and begin the extraction (without the nickel in place). If not, dump the ground coffee back into the doser and adjust accordingly. Using too much coffee is definitely not the thing to do. The coffee will not have room to expand which will negatively affect the extraction. The coffee will also directly contact the shower screen making a mess. Using a bit too little coffee is better then using too much.

      The problem with the above-described dosing-volume test is that not all machines react equally. Some machines handle lower doses quite well. While other machines are very sensitive to dosing variations.

      What's the next step? Taste the espresso, of course. Now what? Experiment. All the above is to ensure consistency. It lets you make other changes and more quickly discover what works, what makes the espresso worse, and what makes it better. Try reducing the coffee by .5 grams and adjusting the grind a little finer until it matches the correct flow rate and volume parameters. How does that taste in relation to the previous efforts?

      When you find something that works.. or doesn't, repeat your efforts exactly the same way a few times to be sure that it was not a fluke. After all this, when you do find something that works you will be able to repeat it, over and over.

      So is this all the final solution, Mr. Holmes? No. What if you go all through this and still find that the results are not what you would expect? There is still the matter of brew temperature. And again, some machines are very easy to adjust and others ave no real adjustment at all. So what else can you control? How about the coffee? If you find that you just can't gt the results you want, try another coffee. Even try some that you normally would not. If you usually use dark roast, try light, and vice versa.

      Remember that coffee is a journey, and you get to eat the road.

Coffee Cup
  -   -   - Silvia
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