How the flavour of your coffee is made: an experiment

Few weeks ago I came across a cool little experiment shared by one fellow on the interwebs – I’d like to give him credit but I can’t find the article – and I thought I’d share it with you. It shows how various flavours of coffee extract in a sequence. First things extracted from ground coffee are acids with sour, vegetal tones. They are followed by sugars, which provide sweetness and some body. Then come tones of chocolate, caramel, and later on spice and tones of earth. The last particle to get extracted are tannins, which are pretty astringent. Tannins are fantastic in wine, but not in coffee, so ideally extraction should end before tannins begin to get released.

This means the speed and length of your extraction (provided it is somewhat even) regulates how many of these flavours will you get into your coffee. Too quick? You’ll get acids and some sugars. Painfully slow? You’ll extract everything all the way to the tannins.


To taste the difference, prepare any dripper you have on your hand. V60 would be the best, but Kalita or Bee House should work as well. Prepare 300g of 95°C water and 20 grams of coffee. Rinse your paper filter with hot water, grind your coffee medium-coarse-ish. Prepare 5 vessels.

Follow a pouring sequence of 5 x 60g of water and extract each pour into a separate vessel. Let the water seep through fully before moving your dripper and beginning the next pour. This way you should end up with 5 vessels with approximately 60g of coffee in each vessel.

Taste them. How is the result? Here is mine:

Surprising results of coffee extraction

The first pour was made into the left-most cup. It was sourer than sour pickles, pretty disgusting and unacceptable to be served, ever. Second cup was very sour as well – there was nothing beyond the sourness, no body, no sweetness, no character. Only with the third cup did the flavours get fuller and rounder, but it was the fourth cup that actually tasted great. Fifth cup wasn’t bad, only bland and boring.

Combined together, they made for a tasty drip from Colombia Asprosi. Separated, they couldn’t stand up to the task

So, next time you make coffee…

…keep this in mind. This is the reason why recommended extraction times for espressos are around 20 – 30 seconds. This is also how you can make your drip more sour (prolong the first pour) or sweeter (shorten the first pour).

I will dive into these later on in Autumn but for now let us keep in mind that the length and speed of extraction affect the flavour of our coffee and so does the pouring sequence and immersion time.

Happy coffeeing good people!

If you have read through the article and came up with some questions, feel free to contact me and I will be happy to answer them.

More resources:


If you would like to dive deeper into coffee preparation at home, take a look at my e-book Home Barista, which deals with all aspects of preparing coffee at home. You can take a look and make a purchase at Gumroad:

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About Petr Klíma