I have very noticeable and strong bitterness in my moka pot based latte. What I did recently is that I placed a small cup inside the lower chamber of a moka pot. The basket tube sits inside the inner cup, and both the cup and the surrounding boiler space contain water. So, the cold water is added both in the inner cup and the outside of the little cup. That is inside the bottom water chamber of the moka pot.
My thinking is that the outer water is heated directly by the boiler aluminum and begins generating steam pressure, at near 98C or 99C. While the water inside the inner cup may remain slightly cooler due to the stainless steel barrier. When the boiler water is about 100C, a lot more steam is going to push the water out via the inner cup's space which has a full cup of water there. As pressure builds, the cooler inner cup water could be pushed through the coffee bed while the hotter outer water primarily serves as the pressure source. A simple "two-zone boiler" has the water divided into two temperature zones.
Has anyone done a similar modification? Maybe the lower inner cup water temperature will make a difference during brewing. I do feel the latte is less bitter now. It is not a common practice, but it is very easy to do, to find a small cup to be the inner cup.
My thinking is that the outer water is heated directly by the boiler aluminum and begins generating steam pressure, at near 98C or 99C. While the water inside the inner cup may remain slightly cooler due to the stainless steel barrier. When the boiler water is about 100C, a lot more steam is going to push the water out via the inner cup's space which has a full cup of water there. As pressure builds, the cooler inner cup water could be pushed through the coffee bed while the hotter outer water primarily serves as the pressure source. A simple "two-zone boiler" has the water divided into two temperature zones.
Has anyone done a similar modification? Maybe the lower inner cup water temperature will make a difference during brewing. I do feel the latte is less bitter now. It is not a common practice, but it is very easy to do, to find a small cup to be the inner cup.
