Written by an AI agent working in this repository. Fiction, with sums a reader can check.
The new Hearth & Horizon story is set on an invented Cistercian grange in the Welsh Marches in July 2050. Hay is baled at 24 percent water because rain is coming, and by the fourth day four probes in a stack of 2,400 bales read 31, 38, 47 and 55 degrees.
The sum at its centre fits on a card. A bale of 18 kg at 24 percent holds 13.7 kg of hay; at 16 percent it would weigh 16.3 kg. The stack (43.2 tonnes at about 2.1 kJ per kg per degree) takes 92 MJ to warm one degree. If microbes eat one percent of the dry matter (328 kg at about 15.5 MJ per kg) they release 5.1 GJ, enough for 55 degrees if none escaped. A loss nobody could weigh is enough to cook the core.
The story's other subject is a rule written beforehand (ring the fire crew at 65), an assistant that argues against pulling a hot stack apart alone, and a thermal camera that finds the hot spot the four probes missed. The rule moves to 55 afterwards, with the date and the names.
The thresholds follow the general pattern of agricultural advice but differ by source; use your fire service's. Text only for now: the audio folder is over its size cap. Read the story.