# Building a Small-Batch Tea Roaster

Small-batch tea roasting benefits from precise, repeatable heat control. A practical benchtop roaster can use a rotating stainless-steel drum, a 500–800 W ceramic heater, and a variable-speed motor. Batches of 100–250 grams are large enough for meaningful tasting trials while remaining responsive to small temperature adjustments.

## Thermal Design

Tea leaves are lightweight and poor thermal conductors, so airflow and drum contact both matter. A perforated drum improves circulation, while rotation at 20–35 RPM prevents scorching. Two temperature sensors are useful: one near the heater inlet and another inside the drum near the leaf bed. The second reading usually lags, but it better represents the actual roasting process.

## Control Configuration

A microcontroller can regulate heater output through a solid-state relay using a conservative PID loop. Heater power should fail off if the thermocouple disconnects, the drum stalls, or the enclosure exceeds its safety limit.

```yaml
roast:
  target_c: 115
  duration_s: 720
  drum_rpm: 28
  max_c: 145
  cooldown_fan: 100
```

## Roast Profiling

A typical green-tea finishing profile starts with two minutes around 80 °C to remove surface moisture, then ramps gradually to 110–120 °C. Holding near the target for six to ten minutes develops toasted aromas without overwhelming the tea’s vegetal character. Logging temperature, heater duty cycle, and drum speed once per second makes successful batches reproducible.

## Cooling and Maintenance

Cooling should begin immediately after the roast. Opening a discharge gate into a mesh tray with forced air can bring the leaves below 40 °C within two minutes, limiting residual cooking. Between batches, remove leaf dust from the heater path, inspect the thermocouple mounting, and verify that the drum rotates freely; accumulated fragments can become both a flavor contaminant and a fire hazard.