Help! My Ratio Four is overflowing!

Overflow can be a pain to deal with when brewing large batches of coffee. Generally, this issue can be resolved with adjustments to one of three variables: dose, grind, and filter type.

Are you dosing too much coffee?

"Dose" refers to the amount of coffee that you are using for a specific coffee brew or recipe. Too large a dose will leave less room in the basket for water as coffee particulates absorb water and slow down the flow of water out of the basket. 

We've published articles on where to start with dose, where we provide some good starting points, as well as articles on why it matters, and how it can be adjusted to fix a brew that isn't tasting quite right.

Is your grind setting causing issues?

Coffee that is too finely ground will restrict the flow of water out of the coffee slurry, or even clog up the holes in the filter completely, both of which will cause overflow. Coarsening the grind setting may enable the coffee slurry to drain more quickly and prevent further issues. The coffee grounds should look like raw sugar, as shown in the graphic below.

Please see our guides on the importance of grind size and how it can be adjusted to fix a brew that isn't tasting quite right.

Are you using the right filters?

The filters that you use in your brewer may lead directly to overflow due to either height or construction incompatibility.

1. Height – The walls of your filter must extend high enough above the basket edge to contain the coffee slurry, but not be so high that they bunch up or fall over during the brew cycle.
2. Construction – Thicker or more tightly woven filters might slow down the flow of water so much that water builds up and flows over the sides, even at the coarsest grind settings. If the filters are too thin, they may not support the coffee slurry and fold over and release the slurry at a higher fill level.

Our Ratio Four filters were designed specifically for the Ratio Four, while our customers have also reported success with Kalita Wave 185 filters as an alternative, but we haven't had the opportunity to test them out much ourselves.

For a deep dive on the subject of filtration, please see our article all about what to look for in a filter and how it affects the coffee in your cup.

One last thing

Your first couple of brews with your Ratio Four are a good time to get to know it. If you experience overflow issues, we suggest keeping an eye on the first couple of batches until you can use the tips above to eliminate the issue. If you have attempted everything above and still are not seeing improvement, please reach out to our team at hello@ratiocoffee.com, and we would be happy to help you sort it out.