Dialing in Espresso: What is it and How?

 

During my brief time in the coffee industry, I have come to realise – a lot of people who are introduced to dialling in espresso find the whole ordeal quite intimidating and seem to think it is far more complicated than it is.  If you are completely unfamiliar with the process, keep reading, but if you are familiar with it and clicked in to see how it was made simple, I invite you to have a look at the last picture of this post.

 

If you’re unfamiliar with the role of a barista you are probably thinking ‘What the fudge is dialling in?’. Don’t worry, I will get to that, but first I need to clear up some other pieces of terminology used in this process.

 

Terminology Used For Dialling In

An espresso is a drink made using coffee, water and a lot of pressure. The coffee grounds are held in a small circular basket with tiny holes at the bottom which act as a filter. This is called a portafilter. Water is pushed through the coffee and the holes at the bottom of the portafilter using high amounts of pressure (normally 9 bar) and in doing so, the flavours are extracted from the coffee leaving the coffee grounds behind.

 

 

Portafilter

• Dose: Refers to the amount of coffee in the basket.
• Beverage weight/yield: Refers to the amount of espresso that is in the cup.
• Time: The amount of time it takes for the water to pass through the coffee and basket and into the cup producing the desired beverage weight.
• Recipe: All of the previous variables combined together to form instructions for the barista.. If you ask a barista what their recipe was, they would reply something like. “18 grams (dose) to 36 ml (yield) in around 25-30 seconds (time).

This seems way too simple right? If you are not a barista you may be thinking, ‘How can that be difficult?’, and Why am I waiting 5 minutes in the morning for a barista to do this!?’. Well, let me ask you a question – what would you do if you were behind the espresso machine and you followed that recipe but the shot time was only 10 seconds? With no training the answer would be extremely difficult to devise. The answer is change the grind size. The grind size is the most important part of the procedure. In a standard set recipe it is the only parameter you need to change. The grind size can slow down or speed up an espresso shot.

Why Grind Size Matters

A roasted coffee bean is roughly 30% soluble. This means 30% of a bean can be dissolved into a solvent, which in this case is water. If you were to put a whole coffee bean into a cup of water it would take a long aul time to extract the 30%. Days, weeks, or maybe even months. To be quite honest, I’m not even sure if it would extract the whole 30%. So to make this bean easier to extract, we grind it. Grinding the coffee bean breaks it down, creating more surface area for the water to interact with. For espresso, we generally aim for 18-22% extraction.

Why? Because, not all the particles available to extract are desirable flavours.

If you extract too much of the coffee, it can taste rather bitter. Too little can taste pretty sour. How do we know 18-22% is the sweet spot? A man that goes by the name Dr Earl E. Lockhart has carried out a lot of extensive research regarding people’s preferences when it comes to tasting coffee, and that this 18-22% extraction is what people preferred.

 

I hear you asking, ‘How can you tell how much coffee you extracted?’. Well, the instrument above is a refractometer and it is used to measure the amount of coffee that has been extracted and dissolved into the water. It does so by bending the light and measuring the concentration of the coffee in the water. It tells you what percentage of the coffee beverage is coffee and what percentage is water. With this information we can do some clever calculations and figure out how much dissolved solids we’ve extracted from the coffee grounds. That’s how we know that recipe I keep banging on about works.

Dialling In: What is it?!

So, what do we mean when we say ’I’m just dialling in’? We are setting the parameters to ensure the espresso is following the recipe we want. In a nutshell, we are changing the grind size. Some baristas are comfortable enough to change the recipe range from 18g of dry coffee in to 36g of espresso out, to something like 18g-40g. Or even just change the recipe by changing the shot time from 25-30 to 30-35 seconds. The reason you would change recipe is if you were trying to achieve a certain taste profile with a particular coffee.

How to Dial In Easily

To make dialling in easy, we will stick to the recipe of 18grams of dry coffee in, 36 ml of wet coffee out, over 25-30 seconds. This is a generic recipe used in the coffee scene today. It is a 1:2 ratio of dry to wet coffee. This recipe is made easy because we only have one varying parameter: the grind size. When adjusted, this will slow down, or speed up the shot. Imagine a glass of rocks and a glass of sand. The sand resembles the finely ground coffee and the rocks resembles coarsely ground coffee. The water would fly through the glass with rocks but would take a lot longer to get through the glass with sand. So, if the shot takes too long, adjust the grind to be coarser and if it’s too short, adjust it to be finer. Here is a very simple and easy to follow diagram for dialling in.

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