Here at Fellow, we obsess over temperature and understand how important it is for brewing coffee. That’s why we created two pour-over drippers, Stagg [X] and Stagg [XF] with vacuum insulated double wall stainless steel to help reduce temperature loss during your brew. Obsessive? Yes. Excessive? No.

The thinking: the more control you have over temperature, the more control you have over your extraction.

But how does our double wall insulated stainless steel dripper actually stack up to competing drippers? We’ve run a series of tests comparing Stagg [XF] Dripper to other popular coffee drippers. For the sake of consistency and accuracy, we focused on testing Stagg [XF] versus flat bottom single wall stainless steel drippers. Here’s what we found:


Our Hypothesis

Stagg [XF]’s vacuum insulation will result in less heat loss during brewing, and by default a more consistent brew temperature throughout the brew cycle.

Our Findings

First, let’s look at “temperature in.” We’re defining “temperature in” as the water temperature used in the pour-over kettle (195 F). We then define “temperature out” as the temperature of the brewed coffee after four minutes.

We consistently measured the final brewed coffee at  5 degrees Fahrenheit hotter than the single wall dripper, as defined by the temperature of the output (the brewed cup of coffee). This means Stagg [XF] is giving you a more consistent brew temperature with less heat loss.


However, that wasn’t the only result that stood out to us. The biggest difference between single and double wall stainless steel is the temperature plot DURING BREW.

Above: The difference in temperature between Stagg [XF] (red line) and other flat bottom single wall dripper (blue line) during brew over time. One note: you are seeing an increase in temperature because so many components are stealing heat from the initial hot water pour (coffee grounds, paper, air, carafe, etc.). At about the one minute mark, you see brewed coffee temp increasing to around desired temp.


It gets very interesting if you look at the “temperature out” plot (the coffee temp) measured over time. We ran a series of tests brewing with Stagg [XF] and other single wall drippers into our double wall carafe with the same pour rates, same coffee, same water brew temperature, etc.

The double wall outperformed single wall in two ways:

  • During the first minute of brewing, stainless steel double wall rises the coffee temperature to the desired temp faster. This is because you’re losing less heat to the atmosphere around you.
  • Once at the desired brew temp, Stagg [XF]’s double wall keeps the air around your dripper from pulling heat away via convection, resulting in a more consistent temp during brew.




The Result

So what does this mean for you and your coffee nerding? Well fellow coffee lover, by having a dripper that better regulates temperature during your brew, you have more wiggle room to play with the intersection of temperature and grind size for extraction. Our friends over at West Oak Coffee Roasters have been brewing with [XF] at their bar at temperatures as low as 185 Fahrenheit. Because they have seen [XF] maintain their desired temperature more consistently, brewing at lower temperatures is possible. Brewing at such a low temp means they can keep the extraction time longer and play with a smaller grind size without risking over extraction. A finer grind plus a longer extraction time at a lower temp can lead to delicate flavors that might not be coaxed out at a faster extraction with less surface area exposed to water. In fact, Conor Poull from West Oak Coffee Roasters competed with Stagg [XF] Dripper in his routine for the U.S. Brewers Cup in Seattle this past April.


Interested? Test it out for yourself and let us know your thoughts and experiments with Stagg [XF] Dripper! Shoot us a note at