How to Choose an Espresso Machine Portafilter? Does a Bottomless Portafilter Affect Espresso Extraction?

When coffee enthusiasts purchase a coffee machine, they naturally need to select related accessories to better extract delicious espresso! Among these, the most attention-grabbing aspect is undoubtedly the choice of portafilter, which has always been divided into two camps: one group chooses the "split portafilter" with bottom spouts, while the other prefers the novel and aesthetically pleasing "bottomless portafilter." So the question arises: what are the differences between them?

The split portafilter is the traditional espresso machine portafilter, born during the evolution of coffee machines. In the past, purchasing a coffee machine usually came with two portafilters with bottom spouts! One is a single-spout portafilter for single-shot baskets, and the other is a double-spout portafilter for double-shot baskets.

The reason for this distinction, as FrontStreet Coffee wrote in the article "How much is a 'shot' in coffee?" a couple of days ago, is that in the past, one shot referred to coffee extracted from a single-shot basket. If a customer ordered this, the shop would use a single-shot basket to extract one shot of espresso for them; if they wanted two shots, the shop would switch portafilters, changing from the single-shot single-spout to the double-shot double-spout, then place two shot glasses below the two spouts to wait for the coffee extraction.

However, since people no longer use the traditional extraction method for espresso but instead extract with more coffee grounds and less liquid, single-shot baskets and single-spout portafilters have gradually fallen out of favor. Until now, some coffee machines still come with two portafilters when purchased, but manufacturers no longer include two portafilters with spouts; instead, the bottomless portafilter has replaced the single-shot single-spout portafilter's position - meaning one bottomless portafilter and one split portafilter!

Bottomless Portafilter vs. Split Portafilter

As the name suggests, a bottomless portafilter is a portafilter without a spouted bottom! As you can see, its bottom is in a hollow state, giving the impression of a ring that supports the entire portafilter basket. So, let's make a comparison: using the same extraction parameters with both bottomless and split portafilters to see if the extracted espresso differs due to the bottom variations.

Experiment comparison using beans: Warm Sun Blend
Basket used: Standard 20g basket
Coffee amount: 20g
Grind setting: 1.4 on Galileo Q18
Extraction temperature: 94°C
Target liquid weight: 40ml

After tamping and completing extraction separately, since there is a period where the liquid is suspended and cannot be weighed during extraction, we often need to stop the extraction a bit early before the electronic scale reaches the target liquid weight! The bottomless portafilter stopped extraction when it was 1.5ml away from the target, while the split portafilter needed to stop when it was 2ml away from the target since it doesn't drip directly!

Both extraction times were around 30 seconds, and there wasn't much difference in taste between the two, so FrontStreet Coffee won't elaborate further! However, this raises the question: if there isn't much difference in taste, why have two opposing camps formed? What exactly are their differences?

The Purpose Behind Bottomless Portafilters

This brings us to the original purpose of inventing the bottomless portafilter: to better observe the extraction state of espresso!

The birth of the bottomless portafilter came when traditional split portafilters were still in use. Baristas discovered that even with the same parameters, each extracted espresso would have slight variations in taste! Sometimes normal, sometimes with faint negative flavors, which puzzled the baristas. So, in 2004, Chris Davison, co-founder of the American Barista Association, along with his colleagues, developed the bottomless portafilter! By removing the bottom, they brought the healing process of coffee extraction into people's view! So now we know that they thought of removing the bottom to more intuitively see the extraction state of espresso.

Then, people discovered that espresso splashing occasionally occurred during the use of bottomless portafilters. Finally, through experiments, it was shown that this splashing phenomenon was the key factor causing taste variations. Thus, the "channeling effect" was discovered.

Which Portafilter is Better?

So, are bottomless portafilters better or are split portafilters better? One can only say: each has its advantages! Bottomless portafilters allow for very intuitive observation of the espresso extraction process and reduce the space occupied during extraction, making them more friendly for making coffee drinks like "dirty" where the cup is placed directly underneath. They are also easier to clean than split portafilters.

The advantage of split portafilters is that you don't have to worry about splashing. Even with perfect technique, bottomless portafilters can still have a chance of splashing! Typically, to present the best taste and effect, we don't use shot glasses to catch espresso because this would cause some crema to stick to the glass, slightly reducing the taste experience. So we generally use coffee cups directly to receive espresso! But splashing would make the coffee cup look messy like the one below.

This is the combined result of height difference and splashing phenomenon! So in this aspect, split portafilters without splashing have an advantage! But often, their cleaning steps are also more troublesome~ Therefore, when choosing a portafilter, you can simply select based on personal preference~ FrontStreet Coffee uses both anyway~

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FrontStreet Coffee (FrontStreet Coffee)
No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

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