This technique is a simple, inexpensive, and effective way to remove fines from ground coffee. I stumbled on this when I dumped grounds out on a paper towel to look at the distribution. After I had pushed the grounds around a little and looked closely at them, I poured them into an Aeropress. Stuck in the absorption pattern of the paper towel were… fines!

It turns out the depth of the depressions in a paper towel is just enough to capture fines and hold onto them when the rest of the grounds are poured off. The basic technique is to spread the grounds out all over the paper towel. Then, lift the paper towel from the long edges, curl it, and pour the grounds into a container. You can shake the paper towel out over a trash can, and it will come out basically clean again.

Here’s a before/after of a medium-fine grind. In this particular batch the paper towel removed about 20% of the grind weight after five iterations.

In case the description of the process has you scratching your head, here are some pictures to show you how it’s done.

1. Pour your grounds out onto a paper towel. Make sure the paper towel has depressions in it.

2. Spread the grounds out, covering most of the paper towel. Leave a little border to reduce the mess.

3. Lift the edges of the paper towel and pour into some type of container.

4. Insult the fines left on the paper towel.

5. Shake the fines out and repeat to your heart’s content.

In one test, I used a normal sized paper towel and 26g of coffee. After about five times, the grounds had lost a little less than 20% of their mass. But I didn’t stop there! I wanted to find the point where the paper towel would come out mostly clean. That happened to be about the tenth time.

I wouldn’t recommend doing this ten times per grind, but I would highly recommend doing it 3-5 times depending on the amount of grounds. This has significantly reduced the amount of over-extracted flavors in my brews, allowing me to brew for longer and enjoy not drinking smoky, bitter cups of coffee.