Extraction in coffee brewing
What is extraction?
Something that is not often talked about in coffee brewing techniques is extraction. Extraction is the action of taking something out and in our case we are taking out the flavours from the coffee grounds. If you can better understand the extraction process in coffee, you’ll be able to consistently brew a great coffee everyday. As you know, coffee is just a combination of coffee beans and water, so how can we bring the most out of our coffee?
What makes a good extraction?
I think a well brewed coffee is a coffee that is evenly extracted. An evenly extracted coffee would mean all the coffee grounds have been exposed to water for the same amount of time. It sounds very simple but there are several variables that affect this greatly: grind size, timing and temperature.
In regards to grind size, it must be evenly ground for an even extraction. Generally speaking the finer the grind, the more even it is. If you’re unsure about whether or not your grounded beans are even, there are devices that can sift your beans such as the Kruve sifter. There are also certain devices with longer drip time, so it may be better to go with a coarser grind.
I’ve done a lot of testing around timing my brewing and I’ve noticed that the coffee is going to be extracted within a two minute window. To test my hypothesis, I used a brewing stand and switched to a new cup every few seconds. I was able to taste each part of the coffee being brewed out. My discovery is that most of the flavours are extracted within the first 45 seconds and after the two minute mark there was an extreme lack in flavour. From my understanding, this is because caffeine is a soluble compound and that’s why most of the flavours come out during this time while the caffeine is being extracted. The rest of the brewing process is to balance out the coffee. For example, espresso is extremely tasty, yet it is extracted in a very short amount of time. You could argue that the espresso is pulled with pressure, but it also has to do with timing. Baristas make up for the strength or texture of the coffee with speed and a metal filter.
The last major factor is water temperature. What is the ideal water temperature and how does it affect extraction? The higher the water temperature the more gases are going to be released initially (first 45 seconds) so the higher the temperature the faster the extraction. However, it becomes harder to control the extraction, since more gases are being released early on, this will prevent the water from being in contact with the beans. If you pour too quickly the water will be forced away without extracting any flavours. In conclusion, my suggested water temperature is under 94 degrees Celsius.
Things to look for when extracting coffee
A well extracted coffee starts from the beginning. When brewing with percolating methods, it’s important the first few drops come out strong. Often people pour too quickly and start with an under extracted coffee so the coffee comes out too thin. In regards to agitation, I am a huge fan of agitating my coffees at the end of the brew. No matter what brew method I use, I will give the coffee a quick stir as it is finishing. The quick whirl gives a last second push to extract everything from the brew.
Hope this helps everyone with their brewing. The basics of brewing a good coffee starts from understanding how the flavours are extracted. We will be writing more blog posts on brewing techniques in the future so stay tuned!
Using a Wave or similar dripper, for my brew to draw down in 2 minutes would require a very coarse grind setting. Old-school brew thinking says that those much larger “boulders” will still have a lot of unextracted solubles left deep inside them. Apparently you’re not finding this to be true, despite what we’ve all come to believe about extraction. Also, how critical is the grinder and the consistency/quality of grinds? Does this method require a narrow particle size distribution or no more so than other techniques?
Hey Dan ~
I’m so glad your coffee has improved because of my tips. Ahahaha the no bloom single pour is quite a fun technique to work with eh? :P
1. For the French Press – I would suggest starting with a touch of cold water to just cover all the beans and then quickly adding hot water to it after. After that just wait two minutes and your coffee is done! Try a 1:14 ratio, you lose a bit of water to the device.
2. The metal dripper isn’t exactly my favourite. I understand that the paper filters are a bit of a “waste”, however if you’re tasting the paper filter then you should rinse the paper filter before the pour anyways.
As for the metal one, this may sound odd but I like using a finer grind size for it. Because it’s a metal filter, it drips quite quickly. So you can slow it down by using a finer grind. People worry if there are fines that drop through. If they did, all the grinds would’ve gone through. So you do not need to worry about it anyways. The super fines will still make it through. Just pour slowly from beginning to end, and try a middle pour as opposed to moving around too much, just pour down the middle without a bloom.
I quite like cloth filters. It’s just out of all the filter types they are the most finnicky. I would advise only using them if you plan to use them every day. I think they just absorb too much of their surroundings smell. Let me know if you have any more questions!
Vince ….I love your coffee techniques ….My coffees now taste better because of your tips….I am now a believer of the no bloom and single pour technique. Anyways you state you use agitation in all your brew methods and usually at the end. Need your inputs on the 2 below.
1 . What’s your tips on French press ?
2. Tips on Metal pour over like Able Kone with less silt . I love coffee but recently my taste buds can sense paper and been exploring paper less drippers and also cloth filters .
Appreciate any help !