FAQ AeroPress

Frequently Aasked Questions

1. Does the AeroPress’ paper filter remove oils that contribute to flavor that pass through the metal filters in my French press and my espresso machine?

We conducted blind-tasting tests with espresso and French press coffee lovers. They tasted paper-filtered AeroPress brew and metal-filtered brew – made with espresso filters and custom filters which were about three times finer. Every single taster preferred the paper-filtered brew.
This is not surprising, in light of the fact that the fine particles which pass through metal filters are quite bitter.

In the book Coffee - A Guide to Buying Brewing and Enjoying, renowned coffee author Kenneth Davids wrote about making drip coffee with metal filters;
“…you may not like coffee made with these filters as much as you like coffee brewed with paper filters. The mesh allows a good deal of sediment and colloids to enter the brewed coffee, which gives it a heavy, often gritty taste, closer in style to French-press coffee.

Also, from the same book and page;

“A note on Filter Papers

Virtually all white filter papers manufactured today are whitened without use of dioxin, a carcinogen that was used in bleaching paper through the late 1980’s. For this reason, I feel confident in recommending white papers in preference to brown, which imparts a cardboardy taste to the brewed water and which may harbor some dubious chemicals of their own, including tars.

2. How can I extract the richest flavour from the ground coffee with my AeroPress?

There are three possible answers to this question.

• Make the grind fine enough. A finer grind will yield a richer brew. If you are using a blade grinder, be sure to run it for 20 to 30 seconds. If you are using a burr grinder or having your coffee ground at the store, set the grinder midway between drip and espresso grind.

• Use enough coffee. Use the AeroPress scoop which is sized to optimize flavor.

• If you are accustomed to coffee with a bite (the bitterness) the smoother brew from an AeroPress without the bite may come across as being less 'strong'. But in fact we have learned that many AeroPress users enjoy their coffee stronger now that they can brew it without the bitterness and with lower acidity. If you wish to try stronger coffee, just increase the amount of coffee used or reduce the amount of hot water used to dilute the coffee ('American style').

3. I have a whirling blade grinder. Do I need to buy a more expensive grinder capable of a finer grind to fully enjoy coffee made in my AeroPress?

We've tested a number of these grinders and find that they work quite well but need to run a bit longer than their instructions suggest. Try about 30 seconds for two scoops. When the grind is fine enough for rich flavor it will tend to stick in the grinder because of static and you may have to help it out with a spoon.

Two scoops of a nice grind require about 20 to 30 seconds press time in the AeroPress. Coarser grinds will run through faster and make a slightly weaker cup.

4. To make a regular American cup of coffee using an AeroPress, you basically brew an espresso and then dilute it with hot water. Why not run a whole cup of water through the press?

We tried just that. But again, in blind-tasting tests everyone said that the coffee tasted smoother when made by our recommended method. Pushing too much water through the coffee extracts bitterness.

5. The instructions for the AeroPress recommend using 80°C ( 175° F ) water. That doesn’t seem hot enough. Why don’t you recommend a temperature closer to boiling?

In developing the AeroPress we spent more time on taste-testing various brewing temperatures than on any other tests. Our tasters ranged from casual coffee drinkers, to coffee aficionados, to professional coffee tasters and consultants. Every single taster preferred brew made at 165° F to 175° F. They said the hotter brews were ok, but the 74° C to 80° C (165° F to 175° F) brews tasted best.

Books often recommend a brewing temperature of 91° C to 93° C (195° F to 200° F). This is good for conventional brewing methods that pass hot water through a bed of coffee. In this method, the water rapidly cools so the lower part of the bed is operating at a lower temperature. However in the AeroPress all of the coffee particles contact the same water temperature during the stirring phase.

Don’t worry about your coffee being too cool.  About the hottest anyone drinks coffee is 63° C (145° F).

6. Why did you include a stirrer with the AeroPress? Almost any spoon will work.

The handle on the AeroPress paddle prevents the tip from tearing the paper filter. It also won’t scratch the AeroPress chamber.

7. Where can I buy more filters?

Each AeroPress comes with 350 filters so you have enough filters to last many months. Replacement packs of 350 filters are available from this website's shopping cart.

9. How can I make it easier to press?

There are two possible answers to this question.

• People who find their AeroPress too difficult to press are usually just pressing too hard. When you start pressing, depress the plunger about half an inch (one centimeter) and hold it. Let the compressed air in the chamber work for you. Several seconds later, press the plunger a little deeper and hold again. Repeat until you hear air escaping from the chamber which indicates all the liquid has been filtered. Now pressing the plunger down to the "puck" of coffee will be easy.

• If pressing gently does not solve the problem, your grind is too fine or perhaps only some of your grind is too fine (powder in the grind). If you are using a blade grinder, run it a little shorter time. If you are using a burr grinder or having it ground at a store, adjust the grinder one setting coarser.

10. When I add water to three or four scoops, why does the mix swell up and overflow?

This occurs with three or four scoops of very freshly roasted coffee when you use water that is hotter than the recommended 80° C (175° F). Try 80° C or even 85° C (175° F - 185° F) water and the problem will disappear. If you prefer hotter water and the bite it will produce in your coffee, limit each pressing to three or even two scoops.

11. Do you have any tips for making water a particular desired temperature such as the recommended 80° C (175° F) temperature?

Yes, we have several suggested methods.

• Using a measured amount of boiling water and then add enough cold water to bring the water temperature down to 175° F (80° C). Pour boiling water into a measuring cup and then add enough cold tap water to increase the total water by a third.  For example, if you measure 1.5 cups of boiling water, add cold tap water to bring the total to 2 cups. 

•Or fill your cold cup or mug with boiling water and let it sit for about a minute. This will reduce the temperature of the water and have the added benefit of preheating your cup.  Then pour the water you will be using for the pressing into the opening of the plunger (!).  By this time, first the mug/cup and then the plunger have removed enough heat from the water. You can verify this the first time with your kitchen thermometer. You can now pour the water from the plunger onto the coffee in the chamber. You can then press back into your mug to make an American cup of coffee or back into your emptied cup to make a regular cup or an espresso in a small cup.

• Many home "instant hot water" systems deliver 80° C (175° F) water or can be adjusted to that temperature. If you have such a system, using an AeroPress is really simple.

• Some electric kettles heat very quickly and have an adjustable temperature dial. You can set the dial to your favorite temperature and you are ready to heat water.

A commonly used and an easy method for heating water to a desired temperature is to use a microwave oven. (The owner of this website doesn't use this method).  Measure the amount of water needed into a cup or other vessel (The plunger has marks so it can be used as a measuring cup.)  and then heat it in a microwave oven.  Use a kitchen thermometer (commonly used when cooking meat) to determine the number of seconds required to heat the water to the desired temperature. (Do not put the thermometer in the microwave oven.)  For subsequent heatings, there is no need for the thermometer.  Just remember the number of seconds required in the microwave to reach the desired temperature for the right amount of water.