The idea is to get a higher shot temperature out of the Forge than would be otherwise easily possible by pre-heating with just boiling water. First introduced on HB by Peter (beananimal) here:
The Forge placed ontop of a Fino 1.2L kettle. My Forge has a small hole drilled in the top plate, which fits an instant-read type of thermometer. To get a more accurate temperature, I also added some Dow 111 to act as a thermal compound. Take note, this reads just the overall metal temperature, not exactly the temperature of the water or steam inside the Forge. Idea was to preheat the “group-head” to around 75C, then lock in the basket and pull using normal 100C boiling water to get a shot temp in an expected 80-90C range.
By taste, I can tell that the method definitely works to pull better highlights out of lighter roasts. So far, I don’t feel it’s necessary for most dark roasted coffees. The normal pre-heat method by using boiling water gives me excellent results. But to prove it a possibility I wanted to show my findings. Next step will be to get some Scace readings. If I can’t find a customer who is interested in doing this test that already has a Scace, I’ll be looking to pick one up. Anyone interested in loaning me theirs?