If you’re lucky enough to have an espresso machine at home (and I mean a proper one, not a capsule machine) then you’ll no doubt have realised that for such a seemingly small and simple drink, it needs a lot of things to get right in order to create the perfect shot of coffee.
So what exactly does it take to make good espresso at home?
When we thinking about good espresso we need to treat it like any cooking recipe. It needs the right ingredients and quantities to deliver the best cup possible. Luckily with espresso, there are only really two ingredients that end up in your cup: Water and coffee.
Be warned though, as simple as that might seem it’s still crucial that we get those two ingredients absolutely spot on. With water we need to ensure that it’s at optimum temperature, and with coffee it needs to be the correct grind size and of sufficient quality.
The better the quality of your coffee, the more you can get away with making mistakes elsewhere in the brewing process. If you use cheap or poor quality coffee then you just won’t have this freedom, and you risk the final shot of espresso being unpalatable.
Beyond this there are a few things you ned to keep in mind when making espresso.
Here are three core ideas to espresso theory for you to get right for your next shot.
#1. Brew ratio
I’m going to stay with the cooking analogy here. If you make a cake and then next time you make it you use double the amount of butter then you would expect different results in the cake’s texture, structure and taste. The same is true with ratios for espresso.
In simple terms, brew ratio is the amount of ground coffee you put in the basket versus the amount of coffee you get in the resulting shot of espresso.
For example, if you put 18 grams of ground coffee in the basket and then brewed 36 grams of espresso then that would be a 1:2 brew ratio.
It doesn’t have to be this ratio however. Some people prefer a 1:1 ratio, and others like 1:3. What’s important to bear in mind is that the flavors of each of these will be very different to one another.
#2. Brew time
In simple terms, brew time is the amount of time it takes to achieve your target brew ratio of espresso. So, if you wanted to achieve a 1:2 ratio shot with 18 grams of ground coffee, then your brew time would be how long it takes your machine to brew 36 grams of espresso.
One of the biggest factors on brew time is grind size. This is a significant variable on all brewing methods, and espresso is no different, with it being one of the biggest contributors towards the taste of your resulting cup of coffee.
Generally speaking, fine grounds will result in a much stronger flavor than coarse grounds, Traditional espresso is made with fine grounds, which is why espresso is often associated with a very deep and intense flavor.
What does this have to do with time? Well, if you think of coffee like sand in a filter with water being poured through it, then it will take water a while to completely filter through it. In contrast, if we have rocks instead then the water will almost instantly drip through. The same is true with fine grounds when compared to coarse grounds.
We want the grounds to be fine so that the water can extract the flavors and aromas as fully as possible from the grounds. The ideal time for this is somewhere between 25 and 35 seconds. If you find that your espresso is brewing in less time than this then its likely that your grounds are too coarse, while if it takes much longer than this then it’s likely that your grounds are too fine.
Why is this a problem? If brewing time isn’t long enough then your coffee will taste weak, while if it takes too long then your coffee will over extract and be bitter and really unpleasant to drink.
#3 Brew temperature
The third and final important concept to understand is the temperature of the water you are using to brew your espresso. Very often you don’t need to worry about this too much because usually machines are automatic enough to gauge and apply temperature properly. However, if you do need to do this manually then the temperature you should be aiming for is 200°F/94°C.
In other posts I’ve talked about brew temperature and the effect this can have on coffee brewing. Often if your temperature is too high then you can risk burning your coffee, but also the water will be too active. This means that it can over extract for coffee, resulting in a bitter and unpleasant taste.
What can impact brew temperature however is the roast level of your coffee. As a general rule of thumb, if you are using a darker roast coffee then you might need to tweak your target temperature slightly to accommodate the richer flavors of the coffee. You might want to lower the temperature slightly, and aim for about 195°F/91°C. Likewise, if you are using a light roast then you should try to increase the temperature slightly and aim for around 203°F/95°C.