Coffee Particle Size Analysis

por Paul Kippax, Tuesday, 8th September 2015

Particle size of coffee and Premium coffee!

How the particle size of coffee can affect the taste and strength of coffee

As a Malvern product manager, I am privileged to get the chance to travel to different locations around the world in order to meet Malvern’s users and engage with our sales teams. As a result, I get to stay in a lot of hotels.

Now, as with other travellers, I have developed my own list of requirements for assessing whether a given hotel is worth visiting again. I don’t know what you would assess (leave your ideas below), but for me there is only one question which needs to be answered: Is the coffee in the room as good as the hotel?

You may consider this an odd metric to choose. However, when I arrive in a hotel feeling jetlagged, the first thing I reach for is the coffee, as I know that I need to stay awake if the jetlag is to be beaten. So, on a recent visit to China, I was excited to find a ‘Premium Coffee Grounds’ sachet waiting for me as I entered by hotel room:

Expectantly I prepared the brew, following the detailed instructions for the in-room coffee percolator provided by the hotel. You can imagine my disappointment when, at the end of the brewing period, I was left with a cup of coffee which was so weak I could almost see the bottom of the cup!

Smaller coffee particle size the stronger the coffee

Of course, as a particle sizing man, I can bring some insight to this situation. As readers of this blog will know, the strength of coffee is related to the coffee grind particle size. The finer the grind, the more intense the coffee flavour. So, I took another sachet and analysed it using the Mastersizer 3000 and the new Funnel Sample Feeder we have just launched.

The result obtained is shown here, along with the coffee particle size obtained for a sachet of ‘Decaffeinated Coffee Grounds’ which were also provided in my room:

As you can see, the particle size of the coffee grind is very coarse, probably explaining the poor taste. Also, it is similar for both the standard and decaffeinated coffees, suggesting both are made using the same mill. I expected the decaffeinated coffee to taste similar, so for the sake of good science I brewed it too. It was no surprise that I retained a reasonable view of the bottom of my cup through the resulting brew!

So, what would I expect of a premium coffee? Well, that is a question of personal taste, and I prefer a coffee which is strong and dark. Indeed, here is the particle size of the coffee I normally drink when I am at home:

A much finer grind, and consequently a much better taste!

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