Brew Me: Espresso

We make home brewing espresso straightforward and simple, here’s a how to guide to give you a good platform for making great espresso every time! With hints, tips and ratios for our own coffee.

Before we get into a step-by-step guide we need to talk about this ‘equation’:

GRIND SIZE – WEIGHT OF COFFEE – TIME

Correctly pulled espresso depends on three factors, the grind size of the coffee particles, the weight of coffee you put in your group handle (coffee basket) and the time it takes to yield an amount of espresso. A good shot all comes down to the ideal balancing point of this and the ratio of coffee:espresso.

What is a coffee ratio?
The coffee you use will have an ideal ratio such as 1:2, meaning for every 1g of ground coffee you use, you get 2g of espresso out. You might add 19g of ground coffee and get 38g of espresso out in the cup for a double shot. 1:2 isn’t the golden rule though, some espresso might taste better pulled as a slightly longer shot and some might be better as a shorter shot. With your starting ratio in mind you then need to bring the other factors into play, as described below.

Grind size
Coffee ground for espresso needs to be finely ground, it’ll look a little powdery. You need a fine grind because the brew time is so short, finer ground coffee has a larger surface area to allow for full extraction of the coffee in a shorter time.

Weight of coffee
Some roasters will give you the ideal weight of coffee to add to the group handle, this will be in the region of 18-20g usually but it can vary. If they don’t start with 20g for a double shot and aim for 40g of espresso out (a 1:2) ratio. Then around the ratio from there to taste. This will mean tasting a few shots in succession to find the ‘sweet spot’ that tastes good to you.

Time
The time it takes to ‘pull’ the espresso shot is the final factor and there is a little more room for manoeuvre here. Most espresso shots will take between 25-25 seconds to pull but there can be some variations and there is no hard and fast rule. Coffee roasters might give you a ratio to use, a weight of ground coffee and an ideal time to extract that shot in. For example 1:2 in 25-28 seconds. Here you might need to use 20g of coffee in, get 40g of espresso out and make sure it all happens in between 25-28 seconds. In this case, if the shot is pulling too quickly, say it extracts the 40g of espresso in 20 seconds, you’ll need to make the coffee grind finer to add more resistance therefore with the same weight of coffee, the water will flow through slower and hit your ideal timeframe. The opposite works if the shot takes too long to extract the required weight of espresso, make the grind slightly coarser, this will decrease resistance and allow water to flow through the ground coffee a little faster.

Ok, with those basic ground rules covered, let’s pull a shot! For this coffee we will say we are making espresso on a 1:2 ratio, the ideal amount of ground coffee is 20g and we’d like to pull a 40g espresso shot in about 30 seconds.

 

1.   Gather your gear
You’ll need:
- Ground coffee
- Espresso machine(!)
- coffee tamp
- cup
- scales
- timer
- milk and milk jug (if making a milk-based drink like a Flat White)

 

2. Weigh group handle

Weigh the group handle and zero or tare the scales. You can now add your ground coffee straight into the basket and weight it all again. The scales should read 20g.

 

3.    Tamp

Shake the ground coffee flat in the basket and tamp it on an even and flat surface. When you are tamping apply a good and even amount of pressure across the coffee. You are essentially trying to expel any air between the particles to allow for even extraction. Remember water will always find the easiest way through the coffee and you don’t want to leave it an easier passage which will cause channelling and uneven extraction.

 

4.  Insert group handle

Flush the machine shower head with water and then insert the group handle. It’s at this point that we also warm our cup with hot water. This is so we don’t ‘shock the coffee by adding it to a cold cup.

 

5. Weigh the cup

Once the cup is warmed and the hot water discarded, place the cup on the scales under the group head and zero them again. Now you are ready to pull the shot straight into the cup and watch the scales read the weight as it fills.

6.   Pull the shot

Start the shot and start the timer at the same time. As the weight of the espresso reaches the desired amount you can switch the machine off, it will have hopefully pulled the shot within the desired time frame. If not, taste it, make grind adjustments and try again! If your machine is automatic rather than manual, you won’t need to stop the machine it will do this for you.

7. Milk?

Add milk (if that’s your thing) and enjoy! We’ll be writing a guide to the best way to steam milk for your flat whites, lattes and cappuccinos soon.

Happy brewing!