A hold is only real at the coldest point of the mass. Air temperature in the tunnel reaches the target long before the compost does, and a probe near the door reads differently from one in the middle.
DMR keeps the difference between air, compost and plenum within 3 degrees Celsius, which is itself a check on whether any single probe can be trusted.
- Probe the compost, never the air, for the hold.
- Both ends and the centre, at two depths.
- Start the clock on the coldest probe.
- Log every probe every hour through the hold.