A guest post from Drinky Coffee founder Oli Baise
How to Get the Most from Your Espresso Machine
So you’ve bought yourself an espresso machine. You’re well on your way to replicating your coffee shop favourites at home.
Unfortunately a lot of people end up feeling underwhelmed by the first espressos that they make at home. The most common complaint that people have is that their shots are sour.
Here we are going to go through a few simple ways that you can avoid the “sour shot” trap and make better tasting espresso at home.
Why Can Espresso Taste Sour?
Espresso tastes sour when not enough of your coffee bean’s soluble compounds have dissolved into your brewing water.
This is more commonly referred to as “under extraction”.
Under extraction generally occurs because of one of three reasons:
There has not been enough direct contact time between your brewing water and your puck of ground coffee.
Not enough of your ground coffee’s surface area has come into direct contact with your brewing water.
Your brewing temperature is not hot enough (dissolving rates decrease at lower temperatures)
As you’ll see, each of the techniques outlined here improve extraction by addressing at least one of these problems.
Brew with Coffee Beans Roasted for Espresso
Coffee roasters understand the specific challenges that people face when brewing espresso and will therefore roast beans that help to minimise these difficulties.
In general espresso blends are roasted darker than beans roasted for other brewing methods.
Darker roasted beans have their flavorful, soluble compounds brought further to the surface of the bean, thereby allowing them to extract more quickly into water.
This is particularly useful for espresso brewing as we have a limited amount of water (and time) to work with, so we need our coffee to extract quickly.
While I’m not saying that you cannot brew a good espresso with lighter roasts, darker roasts will be more forgiving if other aspects of your brewing technique aren’t completely on point.
Our meduim/dark roast Bolt coffee is perfect for beginner espresso makers.
Warm Up Your Machine Before You Pull Your Shot
Espresso should be brewed at between 91 and 96 Celsius for optimal extraction to occur.
While most espresso machines will heat up your water to this temperature, by the time it has gone through cold metal tubes and hit your coffee puck in your portafilter, this temperature will be well below 90 Celsius.
You should therefore warm up your machine’s internal pipes and portafilter prior to pulling your shot.
This will increase your brewing temperature and therefore your extraction rates.
The easiest way to do this is to pull a couple of blank shots, that is shots without any coffee in your portafilter, prior to brewing.
This will heat up your machine to the point where it will actually brew at between 91 and 96 Celsius.
Use Pressurised Portafilter Baskets if Brewing with Pre Ground Coffee
While you can brew espresso with pre ground coffee (just remember to tell us to grind your coffee for espresso and we’ll grind it finer than usual), your brewing water will run a bit faster through pre ground coffee than through freshly ground.
This is because once you grind coffee it starts releasing carbon dioxide. The additional CO2 in freshly ground coffee will slow down the rate that your water will flow through it, thereby increasing extraction.
You therefore want to use a pressurised portafilter basket when brewing with pre ground coffee.
Pressurised portafilter baskets differ from non-pressurized portafilter baskets because they only have one hole in the bottom that your liquid espresso can run through. Non-pressurised have hundreds of such holes in their bottom.
The red circle shows the singular hole in the pressurised portafilter basket
The pressurised portafilter basket’s singular hole acts as a bottleneck to your brewing water, slowing down the rate that it can flow through your bed of coffee. This extra direct contact time will result in greater extraction and create a better flavoured espresso.
Some people get very snobby about using pressurised portafilters, saying that they do not create “real” espresso (whatever that means).
In my experience you’ll only notice a difference in flavour between espresso brewed with a pressurised and non pressurised portafilter basket if you have drunk a lot of espresso and have developed a palate properly tuned to its nuances.
I’d therefore suggest starting with pre ground coffee and a pressurised portafilter basket, and then moving onto grinding your own beans and using a non-pressurised basket as your palate becomes more refined (it takes time for this to happen).
If Grinding Your Own Beans Then Use Grind Size to Adjust Flavour
If you’re grinding your own beans, then the best way to change your espresso’s flavour is to adjust your grind size rather than playing around with the quantity of ground coffee and water you brew with.
Trying to change your espresso’s flavour by messing with quantities of coffee and water is like trying to hammer a nail with a sledgehammer - the slightest adjustment can make a huge change in output.
Adjusting your grind size is a much more fine tuned way of modifying your espresso’s taste. As a general rule of thumb:
A coarser grind will reduce bitterness as this lowers extraction.
A finer grind will reduce sharpness as this heightens extraction.
A good starting point with grinding correctly is to grind as fine as you can until your espresso becomes harshly bitter and then go back one setting.
This should give you the highest level of extraction without going overboard.
Brewing espresso can be a bit more finickity than making a filter coffee, largely due to the limited amount of time and water you have to get a good extraction.
These four tips should help optimise extraction efficiency and help you pull better shots at home.
This article was contributed by Oli Baise. Oli is a barista who runs the coffee blog Drinky Coffee.