Fellow Prismo Review: Is This Aeropress Attachment Worth It?

If you own or have researched AeroPress, you know that it is often marketed as producing coffee or espresso. But that’s not strictly true, and it produces a concentrated shot of strong coffee with some similarities to espresso.

Is it possible to make real espresso with an AeroPress? No, sorry to say, but the laws of physics forbid it. However, it is possible to get a little closer, which Fellow promises with the Fellow Prismo AeroPress attachment.

Given that AeroPress already makes a strong shot of coffee, is the Prismo worth your money? How different is the coffee? Find out in this review.

Summary: The Fellow Prismo

• Simple attachment that allows an AeroPress to produce espresso-like coffee.
  
• Never leaks allowing a longer steep time without inverting.
  
• The reusable metal filter is environmentally friendly and produces a fuller-bodied coffee.

The Prismo is an excellent addition to your coffee setup, not just for making faux espresso but also for regular immersion brewing.

– Customer

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The Full Fellow Prismo Review

The Fellow Prismo is an AeroPress coffee maker accessory that replaces the standard filter attachment. The claim is that using the Prismo produces a shot of coffee with a heavier body and fuller mouthfeel than the standard AeroPress, plus a layer of crema resembling espresso. How does it work? And more importantly, how well does it work? Let’s dig into the details.

Fellow Prismo Review

• Design
• Ease of Use
• Coffee Quality
• Cleaning and Maintenance
• Value for Money

3.7

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Design – 4/5

Fellow products are always attractive and well-made. The Fellow Stagg kettle, Fellow Monty and Carter mugs, and Fellow Ode grinder quickly became award-winning style icons among home baristas (1). In the case of the Prismo, a plastic screw-on lid with a valve can only be so appealing, but it won’t ruin the aesthetics of your AeroPress.

The Fellow Prismo AeroPress attachment has two components. There is a plastic screw-on cap, a small rubber pressure-actuated valve in the centre, and a 150-micron metal mesh filter screen. It is embossed with the Fellow logo and has a rubber gasket around the outside to ensure a tight seal.

The one-way valve is designed only to open when a certain amount of pressure has built up behind it. Forcing brewed espresso through a small opening to increase pressure is a familiar concept you might recognize from the pressurized portafilters used in espresso machines.

It would be interesting to know what pressure is required to open the valve, but Fellow hasn’t made that knowledge public. According to the AeroPress website, it operates under a pressure of 0.35 to 0.75 bars. An espresso machine typically extracts at 9 bars of pressure (2). So we can assume the Prismo falls in the lower end of that range. The Moka pot, another brewing device that makes pseudo-espresso, uses steam to reach a brew pressure of 1.5 bar (3).

The Fellow website states that the Prismo isn’t compatible with the AeroPress Go (or any AeroPress released between 2005 and 2009). This is surprising, given that the AeroPress Go has the same diameter and uses the same paper filters as the regular AeroPress. I’d love to get my hands on an AeroPress Go and experiment. Perhaps it doesn’t have the required capacity, or the design doesn’t work with the increased pressure.

Ease of Use – 4/5

Using the Prismo is as easy as using an AeroPress coffee maker – easier in some ways, as you will see. The brewing set-up is nearly identical. Instead of attaching the plastic filter cap and paper filter as standard, screw on the Prismo with its metal filter.

You will likely want to vary your recipe slightly to create a more espresso-like brew. I succeeded with Fellow’s recommended recipe, but as with any time you’re brewing coffee, it’s always worth experimenting to find the best conditions for your coffee beans and taste buds. As a general guideline, I suggest using a finer grind, a higher ratio of freshly ground coffee to water, and a hotter water temperature than your typical AeroPress recipe.

Try this to brew a quasi-espresso with your Prismo:

1. Set up your AeroPress in the standard (not inverted) way.
2. Add 20 g ground coffee and 50 mL of boiling water to the brewing chamber.
3. Stir vigorously for 10 seconds to fully saturate the coffee grounds.
4. Let steep for 1 minute.
5. Press the plunger to filter the coffee.

Step 5 is the only one that is more challenging when using the Prismo, thanks to the finer grinder and the higher pressure needed to force the brewed coffee through the pressure-actuated valve. Make sure your arm muscles are up to the task and choose a sturdy mug. This is not the time for that dainty antique teacup.

A Note About the Inverted Method

If you’re an AeroPress enthusiast, you’re almost certainly aware of the inverted method. It was developed because when using the AeroPress, as initially designed by inventor Alan Adler, some water would start leaking through or around the paper filter even before the plunger was pushed (4). This led to under-extracted coffee and eliminated the possibility of long steep times. To avoid this effect and achieve a more balanced flavour profile, many baristas started setting up their AeroPress upside down – aka the inverted method.

The inverted method has its downside; it’s precarious. Instead of standing on its solid base, the AeroPress is upside down and balanced on the top of the plunger, not exactly a situation you want when boiling water is involved.

Enter the Prismo.

Thanks to the fine metal mesh filter and its rubber seal, it never leaks. There is no need to invest in it. Many people buy and enjoy Prismo for this reason rather than brewing espresso. You can add a paper filter atop the metal filter, so you still get the clean cup of a classic AeroPress coffee. This double purpose makes it one of the best AeroPress accessories.

Coffee Quality – 3.5/5

Let me say right off the bat the AeroPress makes excellent coffee. Its rich, full immersion brew is one of my favourite coffee brewers, especially using the best coffee for AeroPress. This review considers only Prismo’s performance and whether it lives up to expectations.

The Fellow Prismo delivers on most of its promises. No, it doesn’t make authentic espresso, but if you read the fine print, it doesn’t claim to. Fellow calls it “espresso-style coffee” on its website.

This is partly due to the one-way valve and higher brew pressure, but just as important is the metal filter, which allows more coffee oils through into the final cup – like when you brew with a French press.

Is it espresso from your AeroPress coffee maker? No, it is not, and it can’t be. While there is no strict definition of espresso, it is widely considered to consist of finely ground coffee brewed under 9 bars of pressure. There is simply no way to achieve that with AeroPress. The plastic itself would crumple, and your mug would probably shatter.

The espresso-like coffee made by Prismo makes an excellent starting point for a latte or other milk-based drink. In this context, it’s difficult to tell the difference between a real espresso shot. The robust and full-bodied shots brewed by the Prismo have the bold flavour and mouthfeel needed to hold up to the addition of sweet, creamy dairy. If you have a milk frother at home and don’t want to buy an espresso machine, the Prismo is a perfect low-cost option for cafe-style drinks.

Want to brew cold brew with your AeroPress? Check out our Puck Puck review.

What About Crema?

Crema, the layer of tan-coloured foam often seen atop a fresh shot of espresso, is considered by many coffee lovers as indicative of espresso quality. This isn’t entirely true. Many factors affect crema, including how recently the coffee beans have been roasted (5). However, since Fellow suggests that the coffee brewed with the Prismo filter will have a layer of crema, I was curious to see if it would deliver.

Note that if you’ve added a paper filter to your set-up, you won’t get any crema, regardless of pressure. According to world-renowned coffee expert James Hoffmann, the metal filter is necessary if you want crema on your espresso.

In my tests, I never got anything close to the thick crema shown in the Fellow marketing. Even using roasted beans very freshly at the finest grind I could muster, I only achieved a soft layer of foam. Again, this doesn’t concern me regarding flavour or quality. Still, you will be disappointed if you’re considering the Prismo because you enjoy a crema layer’s look, taste, or texture.

Cleaning and Maintenance – 4/5

Cleaning the Fellow Prismo attachment is more complex than cleaning the AeroPress alone, but I don’t think this should dissuade you from buying it. It’s an inevitable consequence of using a reusable metal filter rather than disposable paper. You can’t just toss the filter in the trash; from an environmental standpoint, that’s a good thing.

Because the Prismo relies on extra pressure and finer ground coffee, you’ll often have coffee grounds caked to the metal filter. To clean it, scrape those grounds into the garbage – or better yet, the compost – and then give it a thorough rinse with water. Make sure none of the fine mesh holes are clogged.

Unlike when using an espresso machine with a 3-way solenoid valve, I rarely ended up with a dry coffee puck that you could tap into a waste bin. More often than not, I was scraping coffee sludge into the compost. Prepare to add 30 seconds of extra work to your morning.

In terms of maintenance, there is nothing to do beyond keeping things clean. Consider washing the whole system with warm soapy water weekly, paying particular attention to cleaning the one-way valve. I never had any issues with the valve clogging, but I could see this happening if you ignored it for months.

Nothing is liable to break in this simple design. But the metal filter is fragile and can fold or bend, so treat it carefully.

Value for Money – 3/5

In the grand scheme of things, the Fellow Prismo is not very expensive, particularly when compared to the price of an espresso machine, and it retails for about £30. Although, we should put that in perspective by mentioning that the AeroPress is only a few pounds more, so you’re doubling the brewer’s cost.

If you have a casual £30 to spare, the Prismo is a good buy. It provides a fun way to experiment with new methods of brewing coffee, recipes, flavour profiles, and drink styles you can make at home using your AeroPress. As coffee gear goes, it’s affordable, especially from a premium brand like Fellow (6). Plus, there are the long-term cost savings (and environmental benefits) of not having to buy paper filters.

If you’re on a tight budget, where $30 is a significant chunk of your disposable income, the Prismo filter isn’t a game changer, and you don’t need it. Save your money, and experiment with different recipes and brewing techniques in your humble AeroPress instead.

Don’t Buy the Fellow Prismo If…

• You’re expecting true espresso: If you want a real espresso shot but prefer to keep the travel-friendly aspects of an AeroPress, we love the Wacaco Picopresso and its less expensive brother, the Wacaco Nanopresso. These tiny, light, and durable espresso makers use a clever built-in pumping system to reach the high pressures needed for a proper espresso. Both are a bit more expensive than the AeroPress and Prismo combination, but they’re significantly cheaper than an espresso machine.

• You just prefer coffee brewed with a metal filter: If you love the fuller body that comes from brewing with metal filters and couldn’t care less about the difference between espresso, quasi-espresso, and strong coffee, you can save money by opting for the Able Disk instead. This metal filter is specifically designed for use with the Aeropress, and you can opt for either fine or standard.

• You have an AeroPress Go: I was surprised to learn that the Fellow Prismo is not compatible with the AeroPress Go, despite the fact that it has the same diameter and use the same filter paper as the AeroPress. Fortunately, you’re not out of luck. The JoePresso is an alternative AeroPress accessory designed to make espresso-style coffee, and it is compatible with both the standard AeroPress and the Go.

The Verdict

Should you buy the Fellow Prismo? The answer is yes If you want an easy way to make a more robust and full-bodied coffee with your AeroPress. I’d also recommend it if you’re tired of using the inverted coffee brewing method to avoid leaks. But if you’re looking for an affordable way to make espresso, the Prismo is likely to disappoint. Espresso machines, with their high pressures and metal components, are expensive for a reason, and there’s just no way to mimic that in a £30 plastic device.

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