What Changes When Adding Filter Paper to Espresso Extraction? How to Reduce Fine Particle Fallout? The Secret to Better Tasting Americano Coffee!

Understanding Fines in Espresso Crema

The insoluble substances in espresso crema—fines (one of the components). They can provide extremely high body to espresso, but at the same time, they also contribute their own bitterness. Because of this, they have successfully gained a group of "haters"! Because their existence affects the taste and cleanliness of the coffee, many people want to remove them.

Two Methods for Removing Fines

Currently, there are two widely known methods for removing fines on the market. The first is one that FrontStreet Coffee often shares: the "simple and crude" method! The specific approach is to scoop off the crema floating on the surface after the espresso extraction, which can remove the fines along with it; the other method appears quite "gentle" compared to the previous one. Because it doesn't remove all substances other than fines, and the operation is very simple—just add a filter paper to the portafilter and moisten it before filling with coffee grounds~

Testing the Filter Paper Method

"Won't this affect extraction?", "Can this really remove fines?" Questions like these are endless. Don't worry, let FrontStreet Coffee test whether this method is truly feasible!

Extraction Experiment: FrontStreet Coffee will extract two espressos with consistent extraction parameters, the difference being that one is a regular extraction, while the other has a circular filter paper (and moistened) added at the bottom. Coffee weight used: 20g, Extract weight: 40ml

Let's jump directly to the completed extraction! The regular extraction without filter paper took 30 seconds; while the extraction with a layer of filter paper only took 26 seconds! In terms of time, we can see a clear difference; and in terms of taste, the espresso with filter paper has less body and less prominent flavor compared to the normal extraction. Through the concentration tester, we can clearly see the authenticity of this theory: the extraction rate of regular espresso is 21.88%; while the extraction rate of espresso using filter paper is 20.23%;

But it's worth mentioning that the fines in the espresso with filter paper are indeed much reduced, almost negligible. Therefore, we can know that the method of "adding filter paper to remove fines" is indeed usable, it just requires some adjustments in parameters.

As expected, after adjusting the grind one setting finer, the coffee taste improved significantly—not only eliminating the bitterness brought by fines, but its flavor became richer than before. So, why does this situation occur?

Why Parameters Change with Filter Paper

Actually, the principle is very simple~ Everyone think carefully, the reason why fines can seep out from the portafilter with carbon dioxide to form crema isn't precisely because their volume is fine enough to pass through the filter holes of the portafilter! And a portion of coffee grounds consists of countless coffee particles of different sizes, so inevitably, some coffee grounds will be stuck in the holes due to their size matching the holes, unable to enter or exit! (You can see this by tapping out the puck after extraction and holding the portafilter against the light)

It is precisely these fines blocking the holes that extend the coffee extraction time. However, the intervention of filter paper changed this situation—no more fines can block the holes! Why? Because there are no holes for them to block! Therefore, after adding filter paper, the flow rate greatly increased. But too fast a flow rate also prevents hot water from properly extracting the aromatic substances in the coffee, so we need to adjust parameters to achieve the ideal extraction state~

When to Remove Fines

Of course, the step of removing fines is not necessarily beneficial for all espresso-based coffees. Americano can become cleaner and much less bitter after removing fines. But milk-based coffees like lattes won't work—without the body and bitterness from fines, it's difficult for coffee to suppress the taste of large amounts of milk, and the mouthfeel will significantly decline! So, FrontStreet Coffee wants to say that both keeping and removing fines have their benefits. Don't ignore their advantages just because you've seen their disadvantages—prescribing the right remedy for the symptom is the reasonable approach~~

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Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473