As a coffee enthusiast, you're likely familiar with the difference between filter coffee and espresso. However, let's delve deeper into the specifics of this contrast in our blog. Join us as we clarify the nuanced differences between filter coffee and espresso.
Water to coffee ratio
First of all you have a totally different ratio of water to coffee. An espresso is much more intense than a filter coffee. For filter coffee you take an average of 20 grams for 300 ml of water. With an espresso you use roughly 20 grams for a double espresso with at least 40 ml and a maximum of 60 ml of water.
The water-coffee ratio is therefore very different. This makes espresso a taste bomb – a very intense shot of coffee with the dominant flavours emphasized while the more subtle ones often don’t make it through. With filter coffee you use the same amount of coffee with a lot more water, with an effect something like putting its characteristics under a magnifying glass. It allows you to detect and experience many more flavours. Filter coffee gives you a very honest and real picture of the coffee. After all, you process the coffee much less than with espresso coffees. This technique is also closest to the cupping technique that professionals use to assess and rate coffee. If you want to know more about cupping we recommend you to read our blog: 'Coffee cupping: what is it and how does it work?'.
Crema
Another big difference between the two types is the ‘crema’, which has to be on a cup of espresso but is nonexistent with filter coffee. The crema or the creamy layer that lies on the surface of an espresso is no more than a collection of all the undissolved particles and oils that are pushed through the ‘basket’ by the pressure. They gather on the surface of the liquid coffee and form the bitter flavour component of your espresso.
This does not happen with filter coffee. And that makes filter coffee much thinner in structure and mouthfeel than an espresso. Depending on the type of filter you use, more oil and soluble substances are filtered from the coffee. You also drink filter coffee in a different way from an espresso. A cup of espresso contains a maximum of 3 cl, roughly two mouthfuls in fact. So you drink an espresso very quickly. You drink filter coffee in a larger portion in a big cup, and thus drink it a little more slowly.
Taste development
In addition to the above, you will notice that the taste of filter coffee evolves as the temperature drops. Why is that? Filter coffee comprises at least 98% water. The water dissolves the various flavour components of the coffee at different times. The taste experience of your cup of coffee is created by aroma (nose), soluble particles (flavour) and insoluble particles (the body or mouthfeel). So immediately after brewing, you will perceive the aroma in particular, through the nose. A greater part of the aroma is volatile and dissipates quickly. The components that contribute to the acidity, taste and mouthfeel need more time to become perceptible.
During brewing, all the components contribute to times. In general, you can say that the first part of your brew is responsible for dissolving most, of and the finest, of the flavours, and for the acidity. The second half of your brew contributes relatively fewer flavours, and it mainly works on the intensity, body and strength of the cup of coffee.
How does filter coffee work?
Let us first state clearly that there is not simply ‘one method’ available. Filter coffee is subject to so many influences and your method will vary depending on the type of coffee. Regardless of the origin of the coffee you use, there are a number of variables that you can play with when making filter coffee.
They are as follows:
- The coffee-to-water ratio
- Time (contact time between the water and the ground coffee)
- The degree of grind
- The materials, especially the way of filtering:
Chemex® Coffeemaker
Kalita
V60
AeroPress®
French press - Temperature
- Type of water
'To measure is to know!'
Perhaps you have already come across terms such as ‘extraction rate’ and ‘TDS’. What do they mean? Tasting alone cannot help a roaster or barista to maintain constant quality and a perfect degree of extraction; objective measurements also help us to reach that goal.
First let me repeat that when we are assessing a coffee by tasting, we are searching each time for the balance of acidity, sweetness and bitterness. The task of the roaster and barista is to strive to balance those components, while, of course, taking the origin into account. Here we must refer to the degree of extraction, which can actually be measured with a TDS meter or a refractometer. The value measured with this device reflects the degree of extraction – in other words, the percentage of the ground coffee actually dissolved in the brew.
Suppose you make coffee with 100 grams of ground coffee. If you let the coffee grounds dry and then weigh them, you could, from a technical viewpoint, have a maximum of 70 grams left over. In that case you have all the possibly soluble particles in the ground coffee dissolved in your cup. You might well think that is perfect, and say: ‘I have made maximum use of my coffee!’ But no, you haven’t achieved it yet, and that is where the big challenge lies in coffee brewing. If you were to drink this coffee, it would taste very bitter and unbalanced.
That is why we strive for dissolving the maximum possible amount of all the positive elements in the coffee. Expressed as a percentage, that is between 18 and 22%, in contrast to the 30% maximum achievable extraction described above. If it is below 18%, you will have an underdeveloped coffee. In that case you will not have all the positive, desirable flavours dissolved into your coffee, which may therefore have a flavour that lacks complexity – which is actually obvious, because components that provide balance, e.g. sweetness and bitterness, are dissolved later in the brewing process. So you have not fully developed the coffee and utilized its finer characteristics.
And if it is above 22% you get the opposite result. In addition to all the desirable flavours, you have also let the negative flavours dissolve into it. They make the coffee unbalanced, which can make it an excessively bitter and sour experience. And its acidity and sweetness are suppressed.