Crema is not an important part of coffee, but for those who like crema, we would like to share some tips for making delicious crema-rich espresso using Leverpresso.
Beforehand, shall we talk about espresso first?
To put it simply, espresso is coffee syrup. The coffee powder is tamped to make a coffee puck and water with strong pressure is passed through it. When water with such strong pressure is used, the components that are relatively soluble in water, fine coffee powder, carbon dioxide, and caffeol (coffee oil), emulsify and become highly viscous.
Also, this process causes fine powder, collagen, and caffeol to float on the coffee instead of settling down. That is crema. This layer of cream is dense and helps to keep the espresso from cooling down quickly.
To sum up, espresso is a mixture of coffee oil, fine powder, carbon dioxide, and coffee components with water forced through at high pressures and temperatures. Among them, crema is the mixture of collagen, fine powder, and coffee oil.
So, there are things that we can do to create the conditions needed for good coffee.
- Coffee beans (coffee oil, carbon dioxide)
- Grinding (pressure)
- Tamping (pressure)
- Lever lowering speed (pressure)
If you check these with me one by one, I think you will get good espresso.
You need fresh, well-roasted beans.
When roasting coffee beans, gas is generated. And as this gas (mainly carbon dioxide) is discharged, it pushes the grease out of the coffee beans, so the oil expunged. It is this coffee oil that causes dark roasted coffee beans to look greasy. This coffee oil plays an important role in the emulsion action and crema mentioned earlier. The problem is that if this coffee oil is exposed to the air for a long time, it dries and acidifies, thereby failing to take the aforementioned action properly.
After a month or two from the roasting date, the coffee oil acidifies. Thus, the above-mentioned action can't take a place properly. So, it is recommended to ask about the roasting date before purchasing beans.
Also, when purchasing ground beans, it is recommended to purchase as small a quantity as possible. This is because when the beans are ground, the surface area becomes larger, which leads to faster acidification and moisture acquisition. The recommended method is to grind fresh beans close to the roasting date just before extraction.
You need to grind fresh beans 'moderately'.
Now, we need to grind the precious beans to a 'moderate' size. If you grind them too small, it may become overly pressurized, resulting in espresso that is too bitter, or even make extraction impossible. On the contrary, if it becomes too large, there is no pressure, so a cup akin to drip coffee may be extracted.
The one on the left is the size of sugar generally used and the size on the right is the size of our beans.
So, we are extracting espresso at a sugar-like size, 0.3~0.5mm. It's a bit larger than the actual espresso (less than 0.3) *. However, it may be difficult to visualize it like this.
* So, when you ask to grind the beans, it is recommended to ask that it be done a bit thicker than espresso, but a bit smaller than for a moka pot.
So, the 18g beans that we gave to the supporters who funded the product were sent at the size we actually use for extraction. Also, we printed the 0.4mm on the label of the product so they can refer to it when using.
If the size of the ground coffee beans is larger or smaller than that scale, adjust the zero point to grind a smaller or larger size. From there, if you adjust the size according to your taste, you can extract delicious espresso that suits your taste.
Let's do tamping.
Now, shall we make the espresso in earnest? To get espresso, you have to tamp the coffee. However, if you use 18g of espresso beans, it can be too much.
Don't panic. First, make an OK sign with your fingers* to make a dosing ring and add the coffee powder. Do not try to put it all in at once, but shake it little or tap it on the floor to do it well.
* Use a dosing ring if you have it
It is necessary to shake it and smooth it out
After that, just press it tightly with the plastic tamper included with our product.
At this time, it is good to press down firmly using the middle of the palm to flatten it. The important point of tamping is to flatten evenly and strongly. If tilted to one side, channeling may occur wherein water is drained to the tilted side!
Normally, the tamping is done with a vertical force of about 20kg. Of course, depending on the degree of grinding or the degree of roasting of the beans, it can be adjusted.
Now, shall we extract? If you have followed the steps so far, you can do it. First, pour hot water with the lever down, then take the lever up and pour in water again. It is designed to allow you to pour more water while the lever is up.
Shall we let it sit a bit (Pre-infusion)?
When the lever is slightly lowered and raised, air bubbles rise like this. You can leave it like that for 5 to 10 seconds. After this process, the water and coffee puck meet and coffee is extracted from the coffee powder.
Shall we push the lever down? You don't need to press it too hard. Just push it down gently with natural body weight.
It looks like 3~4 seconds here, but it was actually extracted slowly for about 30 seconds.
If your arms are too far apart, you can't create pressure. You just need to put your arms down close to your body. The closer the shoulder and the lever, the easier it is to extract. However, if the shoulder line is over the Leverpresso, unstable and excessively high pressure may cause injury, so be careful!
If it goes down too fast, it's either that the grind is too large or the tamping is too weak. If the lever is too tough to push down, the grind is too small or the tamping is too strong. If you adjust the parameters by remembering to this, you will surely be able to extract the espresso that suits your taste.
You can make delicious coffee using new Leverpresso's basic tamper and cup alone.