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This Little Gadget Is the Key to Espresso-Strength Coffee at Home

It's not exactly espresso, but it does make for some really tasty shots.

by Maciej Kasperowicz | July 13, 2020

People have been asking me for recommendations about making espresso at home for a long time. And for a long time, I’ve responded with a half-joking “Don’t,” before attempting to be helpful by going into the usual list of questions about how much money they’re willing to spend, and how close they’d need to get to the kind of true espresso they’d get in a coffee shop to be happy with their purchase.

This spring, when I was making some at-home brewing content for Trade’s Instagram, we started getting tons of questions about one particular espresso-simulation gadget: Fellow’s Prismo AeroPress® Attachment ($25). The Prismo is an attachment that replaces the Aeropress’ filter cap and has a built-in metal filter that replaces the paper AeroPress filter as well. Eventually I realized that I not only needed to grab one of these to answer questions about it, but (being relatively stuck inside along with the rest of New York City) I really missed drinking espresso while also having access to tons of coffees fun to make espresso with.

The AeroPress is already marketed as an espresso maker, but while I love the AeroPress to death for making filter-strength strong coffee, I’ve always found making anything close to espresso-strength coffee with it pretty tough. Its paper filters don’t let through enough oils to simulate the body of an espresso, and even with metal filters it doesn’t create enough pressure to easily extract a really strong espresso shot well.

The Prismo differentiates the AeroPress in a few ways. First of all, its filter cap has a rubber gasket that, when the filter is screwed in, creates a much tighter seal than the regular AeroPress. And, instead of a fairly open bottom, it has a valve that really only opens when the plunger is inserted, forming a seal and changing the pressure inside the brewer. That means that you don’t need to invert the brewer to stop the water from dripping through, and it also means that — while it still doesn’t touch the nine bars of a real deal modern espresso machine — it does create considerably more pressure than the AeroPress. You’ll notice this as some of your shot starts shooting through the valve immediately as you insert the plunger — before you even start pressing.

That pressure also allows a closer facsimile of crema than a regular AeroPress, especially if you’re using a darker roast or a super-fresh coffee. It’ll dissipate faster than crema in a regular espresso, but it’s there. Crema is formed by coffee oils and water emulsifying around little bubbles of carbon dioxide, and fresher coffees will have less of that CO2 still in there than older ones, while darker roasts have more of it built up in the first place. To be honest, I don’t personally care that much about crema, even in real espresso (maybe that’s a separate conversation!), but the fact that there’s enough pressure there to make some is a good sign for the AeroPress espresso coffee maker!

After a month and change of playing with this AeroPress brewing gadget, my recipe isn’t that much different from the manufacturers’ AeroPress recipe, though I added just a bit more agitation and total time. I really think you need as much extraction oomph as possible when working such a strong coffee brewing ratio. There have been recent studies that say you actually want to grind coarser for espresso to achieve high extractions (meaning, more or less, lots of sweetness), and while those make a lot of sense, they don’t apply here. While coarser grinds can decrease channeling (the desire of the pressurized water to want to shoot down certain “channels” that form in the coffee bed and skip over other parts of the puck), we’re going to do enough stirring here to make sure all the grinds are pretty evenly wet. That stirring is all the more important, because we're using small amounts of water that will get saturated with coffee particles real quick. Moving the water around a bunch will help expose the least saturated parts of our slurry to more coffee grounds.

When we make a true espresso on a machine, we often measure the output (ie what a scale below our shot glass tells us is the weight of the shot). This is unlike most other brewing methods, where we’re fine just measuring the input (how much water you’ve poured onto the coffee). For a Prismo shot, you’re going to be doing the latter. If you usually brew or have in the past brewed regular espresso, you might want to weigh your resulting beverage and compare it to what you’re used to in espresso.

For example, an espresso shot I brewed this morning using 70 grams of water and 20 grams of coffee ended up weighing 52 grams. Another I brewed using 50 grams water and 20 grams of coffee came to 33 grams beverage weight. That’s interesting data to have for translating espresso recipes, and it actually impressed me with respect to how much water the Presto squeezes out of coffee grinds, which are pretty good at absorbing water and not letting it go.

As always, this AeroPress recipe is only a starting point. As a coffee lover, I tend to err on the side letting the flavor in these shots spread out a little more, so I tend to pour 60 or 70 grams of water, but 50 grams will probably give you something closer to coffee shop concentration. I find it really hard to over extract with concentrations this high and without the pressure of a regular espresso machine, but if the bitterness of the shot overwhelms the sweetness and acidity, by all means grind a little coarser and/or shorten your brew time by 15 seconds the next time out. So here is how to make espresso-strength coffee with AeroPress technology!

Instructions:

  1. Twist the Prismo attachment onto the bottom of your AeroPress. Place the ground coffee on a scale
  2. Grind 20 grams of coffee as fine as possible and put it into your AeroPress chamber
  3. When water comes to a boil, start your timer and pour 50 to 70 grams of water into the AeroPress
  4. With a spoon, stir until the timer hits 30 seconds (stir as vigorously as possible without making a mess)
  5. Place your AeroPress onto the vessel you’re going to press into and cover — but do not insert — the plunger
  6. At around 1:25, insert the plunger and plunge firmly all the way down, using your body weight as much as possible
  7. Enjoy your AeroPress espresso straight or add milk in your favorite mug. If you find the taste to be too bitter in flavor, grind the coffee beans slightly coarser next time you use the AeroPress coffee maker.