The regrettable truth is that many people think that coffee is just a push of the button. I recall another discussion with a fellow barista who mentioned to me he thought making espresso simply suggested pushing a button, before he started working in the trade.
However, I was grateful to my partner as I realised how crucial it was to write this piece on coffee extraction. So keep reading to find what in fact goes into coffee making and what other skills are required to make delicious coffee, apart from outstanding button pushing skills!
Coffee extraction: what is it?
The evolution of coffee extraction
Coffee extraction is the process of dissolving tastes from coffee into water. It sounds exceptionally simple in theory, I grant you. Unfortunately, if we put raw, green coffee beans into water, very little happens. Gradually we have actually discovered that there are different factors which increase the level of extraction, which indicates more coffee properties or Total Dissolved Solids (TDS) in the final cup of coffee.
The very first of these aspects is heat. Our forefathers very quickly understood that putting raw coffee beans in hot water produced more of a reaction compared to soaking raw beans in cold water. They found that, if they didn’t heat the water, they required to leave the coffee beans soaking for much longer in order to get any sort of taste at all in their brewed beverage. This highlights the 2nd aspect that affects coffee extraction: time. The longer the of time the coffee touches the water, the more soluble compounds it extracts.
Nevertheless, this initial coffee drink was still remarkably unsatisfactory and tasted essentially like the bitter plant that it was. Those ancient baristas needed to find a method to increase the level of extraction from the coffee. Then one genius probably believed: if hot water draws more properties from the bean, then undoubtedly it stands to reason that heating the beans over fire before putting them in hot water might release more of the coffee bean properties?
Eureka! Cooking or roasting the coffee beans before boiling them in water was the crucial to coffee making as we know it today. This opened a whole world of coffee for those innovators. When we roast coffee we soften the internal cell structure of the coffee bean which allows us to draw out far more properties and tastes from the coffee bean.
This was the way coffee was most likely obtained for several years and years. Eventually, some smart coffee lover had the idea of squashing the roasted beans and making this ground coffee. Grinding coffee is the last primary element which vastly increases the extraction of TDS from coffee beans. Grinding coffee increases the surface location of the coffee that touches with the water, hence increasing extraction.
So there you have the 3 main factors that affect coffee extraction:
- Time
- Heat
- Grind size
We can break these elements down much further but for now let’s stick to these 3 headings. All variables in coffee extraction are interlinked. If we alter one element, it impacts the others and we have to adjust them too. I’ll speak about this in more detail a bit later.
What are Over-extraction and Under-extraction?
Primal coffee drinkers became so excellent at extracting the coffee properties that they began going too far. They understood that it was possible to have a lot of dissolved solids in the beverage, changing it from a tasty beverage to something bitter, horrible and undrinkable. There is in reality a sweet spot for extracting coffee. In the early days of making coffee with raw green beans, the coffee was under extracted. Eventually, when all of the coffee preparing factors were determined and included to the process, coffee started to be over extracted.
Clive coffee highlights how different coffee solids and tastes are extracted in a specific order when preparing. Fats and acids are extracted first, then sugars, and finally plant fibers. The goal is to brew the coffee for enough time to get a perfect balance of these properties in the cup, but not long enough to draw out the unwanted, bitter compounds.
For that reason, various levels of extraction lead to various tastes in our coffee
. Under extraction If we don & rsquo; t apply enough of one or more of the extraction factors, we will get a coffee that is under extracted. For example, if the ground coffee isn & rsquo; t in contact with boiling water for enough time, the coffee will be under extracted. Under extracted coffee tastes sour, salty and lacks sweetness, as the sugars have actually not yet been drawn out to harmonize the oils and acidity.
Over extraction
If coffee is over extracted, nevertheless, it will taste bitter, due to too many of the bitter plant fibers being pulled out from the coffee. Counter-intuitively, these plant fibers are the only properties that can be extracted from raw coffee beans without the addition of heat, which is why green coffee beans taste extremely bitter and unpalatable.
The extraction sweet spot
That perfect extraction point that we are intending for will yield a beverage that is sweet, with suitable level of acidity and a long finish ; the finish being the instant sensation that we experience after taking a sip of the coffee.
The extraction process
So, for all modern types of coffee brewing, heat, time and grind size are all aspects that require to be considered when preparing a cup of coffee. In some cases one aspect can’t be changed for a particular reason for a particular brewing method. Therefore, the other aspects have to be adapted to fit in with the set element. Let & rsquo; s examine every one separately. Grind At a fundamental level, the finer the coffee is ground the more coffee is extracted. This is due to the increased surface area that is in contact with the water.
With every coffee making method, the grind size is picked based on a number of elements.
These all have to be thought about when considering the grind for a brew.
With drip coffee, the grind can’t be too great or else the water would take too long to go through the filter.
With French press, the filter screen is much larger than a paper coffee filter in basic French pots. This means that the grind normally needs to be coarser for French press than for filter coffee.
On the other hand, espresso has the additional aspect of pressure throughout extraction, which further accelerates the brewing process. The grind therefore requires to be much finer for espresso due to the added force of the pressure forcing the water through a smaller space in between the coffee grounds, at a quicker speed.
Finally, cold brew coffee is ground coarse to help the water drip more quickly through the coffee grinds. Due to the a lot longer extraction time, fine ground coffee also tends to be over extracted when cold brewing.
Grind size can be adjusted minutely for all making approaches in order to discover that best extraction. Nevertheless, all coffee preparing approaches have a standard grind size to follow. The grind size that allows for best extraction for each technique has actually been painstakingly learnt over the period of many years.
Grind sizes for basic brewing techniques are as follows:
- Cold brew - Coarse
- French press - Coarse
- Drip - Medium grind size
- AeroPress - Fine
- Espresso - Extra fine
- Turkish coffee - Powder
Brewing Time
As with finer grind, longer brewing time equals higher extraction. Numerous preparing techniques have actually a specific brewing time.
For example, Drip coffee machines have a standard set time that they take to brew coffee. This implies that the grind size and heat need to fit with the set extraction time in a drip coffee maker. In drip coffee this translates to a medium grind size and water that is almost at boiling point.
The perfect time for standard espresso extraction is between 20 and 30 seconds. The grind size and the temperature level are for that reason minutely calibrated in espresso preparation so that an espresso is pulled out within this time frame.
Cold brew doesn’t use heat in the preparing process at all. For this reason, cold brew needs a much longer period for extraction compared to hot coffee brewing. The longest time for most hot preparing techniques is around 5 minutes. Cold brew takes between 12 and 24 hours to draw out appropriately, which is a significant variation.
Brewing Temperature
Temperature (heat) is the last aspect that increases the rate of extraction. The hotter the water, the quicker and higher the extraction. Therefore, if there is already a greater level of extraction from a particular preparation method due to other formerly pointed out factors, the water temperature level doesn’t need to be as hot.
Espresso coffee has a fine grind and a fast extraction time due to the addition of pressure. Therefore the water temperature level requires to be a little cooler than for other preparing techniques in order not to over extract it.
Filter coffee water needs to be hotter to encourage more of a reaction with the coffee, due to the lack of pressure.
Pour over coffee and French press coffee require to be hotter once again. This nevertheless is mainly due to the direct exposure of the water to the air. The open air nature of these preparing methods causes the water to cool rapidly, which is combated by making with water at a higher temperature.
Roast Level
Although I didn’t include roasting as an aspect that influences extraction, it is very much something that needs to be talked about here; so much so that it gets its own section. A coffee extraction process will always have to be changed for the type of coffee roast you are using.
Similar to the actual extraction procedure, coffee beans can be roasted differently in order to promote greater or less extraction. The primary aspect that we are discussing when it pertains to roast, is time.
The longer the coffee bean is roasted, the more flavors are released from the bean and are for that reason extracted easier during brewing.
This is the reason that dark roasted coffee is usually believed to be stronger than light roasted coffee. This belief was established by individuals who use the same brewing recipe, no matter roasting time. Coffee that is roasted for longer is extracted quicker, therefore it stands to reason that dark roasted coffee requires less of each brewing factor in order to extract efficiently. This implies less time, coarser grind and cooler temperature levels. If preparing aspects are adapted to compensate for a darker roast, dark roasted coffee can be prepared to be the very same as or weaker than a lightly roasted coffee, and vice versa.
So, hopefully, I’ve convinced you that preparing an excellent cup of coffee includes more than great quality devices and dexterous thumbs for button pushing. With any luck, you have also found out a little more about coffee preparation which will allow you to make your home brew that bit more tasty!
Other relevant information on coffee extraction and coffee making: Click for more