Now you’ve chosen your shiny new machine, your grinder and your Two Chimps coffee, it’s time to set up your espresso machine.
Making sure your machine is set up correctly is fundamentally important in ensuring every cup of coffee you serve is perfect.
Many variables can affect the way your coffee tastes, and with a bit of trial and error, we will work out what is best for your machine. Variables include:
- The grind size
- The amount of coffee per cup
- The time it takes for the coffee to be extracted
- The basket size
There are also some basic guidelines to follow that will help you get the best espresso, such as a 1:2 ratio and extraction time of 20-25 seconds. Don’t panic, however! I will explain more about these later on.
Every espresso machine is different; from the size of the machine, down to the size of the portafilter basket, and it is our job to make sure everything runs smoothly.
The best place to start is with the portafilter. The portafilter is the handle that detaches from the coffee machine group head. Determining how much coffee the basket holds is essential.
If there is too little coffee in the basket, the gap between the coffee and the shower screen in the group head will be too big, and you will end up with wet coffee mush in your basket.
However, if you overfill it, then there won’t be enough room for the water and the coffee to expand, and you may end up with a dirty showerhead and bitter coffee. A good sign is that when you knock the coffee out, the coffee puck should come out in one piece, leaving very little stuck inside the basket.
Most baskets will hold between 16-20g of coffee for a double espresso. Some baskets will have the weight written on the outside, and some may have a groove on the inside. If you’re unsure what amount of coffee your basket holds, then we need to work it out.
Working out the size of your portafilter
Start by measuring out 20g of coffee into your basket, tamp and see how big the gap is between the coffee and the top of the basket. If there are 4-6 millimetres gap, then this is probably about right, if the coffee is near the top, you have too much. If you can put your portafilter into the group head, remove it and there is a pattern on the coffee, it is overfilled. Try this again with 19g, 18g etc until the amount of tamped coffee looks visually correct and it doesn’t mark when attached to the group head.
Once you’ve determined the correct weight of coffee for your portafilter basket, we need to work out the correct grind size for your machine.
If your coffee is ground too coarse, the water will run through it too quickly. This means that the coffee won’t have had enough time in contact with the water to bring out all the flavours. This is called under-extraction, and it means that your coffee will have a very sour taste.
On the other side, if your coffee is too fine, then the water will take too long to come through it, and you’ll end up with a bitter-tasting coffee.
Imagine two jars. One is filled with pebbles and the other with sand; you pour water through both. The water will always find the quickest way through, and as you can imagine, it would flow fast through the pebbles but slowly through the sand. The same can be said with coffee. If the coffee is coarse (like the pebbles) it runs fast, whereas if it is too fine (like the sand) it will trickle through.
It should be clear on your grinder how to adjust for coarser and for finer. Grind the correct amount of coffee into your basket as worked out above, tamp and put it into the group head. Place a set of scales underneath the filter spout and a coffee cup on top of this. Tare the scales to 0. As soon as you press go, press start on a timer. Keep your eye on the scales; you want the final weight to be as close to double the amount of coffee that went in the portafilter as poss (a ratio of 1:2.) When you press stop on the espresso machine, also press stop on the timer.
Using general guidelines, it should take around 20-25 seconds for the coffee to reach the correct weight. If it has taken only 15-16 seconds, then we know the grind size is too coarse. If it has taken 30+ seconds, then we know the grind is too fine.
Adjusting your grind
We now need to adjust the grind size and try again. You’ll need to do this several times to determine the correct grind size. Every time you change the grind, you’ll need to discard a few seconds worth of grind as this will still contain some of the last grind size and this will affect the extraction.
Continue with this method until you have worked out the correct grind size that gives you a 1:2 ratio of coffee in vs coffee out for a double espresso, within 20-25 seconds, at the correct weight for your basket and a great tasting espresso. Even though espresso has a strong flavour, there is a sweet spot which we will be able to find. This means we’ve found the exact recipe for that coffee which gives us a perfect taste, without any bitterness or sourness.
You can now adjust your grinder time setting to grind out the exact amount of coffee for your machine. You can also adjust your machine to pull the correct amount of water through. This will mean that you are now able to pull the perfect shot every time. You won’t need to weigh out and adjust each time.
1:2 is the traditional ratio for espresso. For instance, you have 18g in your basket, look for 36g in the cup. Other ratios include 1:1 and 1:4; for a ristretto and lungo respectively.
For a single shot, use the single basket in the portafilter. You should only need, say 9g of coffee (half your double weight) and this should extract in the same amount of time as the double. Don’t worry too much if your single basket doesn’t always knock out cleanly. Due to the difference in contours between a single and a double basket, the water cannot flow through so easily; leaving a little more residue behind.
Certain factors will mean that you may need to tweak certain variables now and again, but only slightly. Temperature is one issue. If the grinder blades are too cold or too hot, they will expand, and this will affect the grind size.
Also, it is a good idea to set up your grinder and machine for every new coffee, due to the differences in coffee beans. Each coffee is different in density and brittle-ness. Therefore will have its unique recipe to extract the best from each lot. It is definitely worth the time to set it up, just to ensure the perfect espresso.
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