Now that you have your lovely espresso machine (see our earlier post on some tipps about this), let me write down some lessons learned about the science of making excellent espresso (as it is a science, not an art).
First things first: Water.
Do yourself a huge favor and only use filtered or bottled water — it not only tastes better but also makes sure your machine doesn’t clog up. Espresso machines are delicate beasts operating at high temperatures and pressures. Using tap water with it’s usually high(er) level of calcium and other minerals can lead to build-up of scale which in turn will clog up your machine (and is a pain to get rid off). Personally I use a BWT Vida filter system — it’s specific filter tech makes water not only free of anything which leads to scale but also makes it taste much better.
Second: Measure.
Espresso is all about dissolving the solubles from your ground beans into water. It’s science — thus measure what you can. Start with measuring the amount of ground beans you put into your portafilter basket. Usual basket sizes are measured for about 18 grams — what you want to get, is a basket which is so full (after tampering the grounds down) that it barely touches the screen inside of your machine. The golden rule is that you want about as much space between your prepped puck and the screen that you can put a coin inbetween. I would experiment a bit to find the right amount of ground beans for your specific setup and the make a mental note of it. From then on fill each basked with the exact same amount of ground beans (as measured in grams).
Next you measure the amount of espresso you pull from your shots. The golden ratio is between 1:1.5 and 1:2. The former is typical for dark roasted beans (more of the Italian style), the latter for, what is called, Third Wave Coffee (i.e. the newer lighter roasts you find in most SF coffee shops these days). Put your espresso cup on a scale while you pull your shot and stop the shot when you hit the right amount. In my case I put 18.5 gram of ground beans into my portafilter and extract 37 grams of espresso.
Measure the time it takes you to get to that extraction — the golden rule is to aim for about 30 sec for the full extraction (i.e. the moment you start your shot until you reached your desired weight). If it’s shorter, adjust your grind and make it a little finer, if it’s longer make your grind a little coarser.
All of this is called “dialing in” — every barista does this at the beginning of her shift. It will take you a bit to find the right settings — the good news is that after you found the right settings, the needed adjustments from there on are minimal (but constant; I tweak my settings more or less daily to stay within those parameters).
Third: Puck Prep
Preparing your puck properly is important. Grind your beans into the portafilter or a transfer vessel (e.g. a small cup). Measure the right amount by weight (see above). As I am using a Niche grinder, which is a single dose grinder, I measure the weight of the beans I put into the grinder and grind a single portion. I am not sure if that works with your grinder but generally speaking I would not leave beans in the hopper – beans get stale within hours of taking them out of an airtight container (which means that you should store your beans in an airtight container once you took them out of the sealed bag). I would always only put as many beans into my hopper as I need for the espressos I am making. Leave the filled hopper to baristas running a busy café.
Distribute the beans using the Weissman Distribution Technique (WDT) — it is easiest with a portafilter funnel (something like this). It makes sure you don’t have clumps which inhibit flow as well as distributes the grinds more evenly.
Some people like to polish off the grinds with a tool like this — I, for one, do this. It creates a more even top surface. The actual usefulness is debated but I like the tidiness.
Once you have your puck prepped you tamp. If you don’t use a calibrated tamper (such as the Force Tamp), try to a) push down vertically without any wiggling and b) about the same force each time.
Fourth: Milk Steaming
It will take you bit of practice to make great microfoam. There is no way around it. But you can significantly shorten your learning curve — watch a couple of videos on YouTube (here are two good ones: https://www.youtube.com/watch?v=6YMgB61WyvE and https://www.youtube.com/watch?v=HIuHvciUS9g — both these channels are great channels to follow).
Use water with a drop of dishwashing liquid for practice – it foams nearly like milk and you don’t waste actual milk in your practice runs.
One pro-tip: Always do a quick purge puff of steam after steaming your milk. Milk likes to gunk up in your steam wand and has a nasty tendency to creep into the steam wand — a quick puff at the end of your steaming will prevent this from happening.
Have fun! It’s a bit of steep learning curve; you will get to good coffee pretty fast if you practice a bit and from there it is the eternal quest to get to the fabled “god shot”.
