Last year, we had a long, gently-cooling fall season which lulled me into complacency to the point that I took too much time with the biomeiler construction, finishing it in below-freezing temperatures. This year, the fall season is cooling at a markedly greater pace. The weather forecast suggests that, even today, if I were to begin a complete rebuild of the biomeiler there would be little hope for me to complete it before the snow falls. After the lesson of last fall, I am greatly disinclined to carry buckets of manure through the snow, again.
So, due to time constraints rather than by choice, the 2025 biomeiler will be a modification of the 2024 system. The primary change will be an increase in the height of the pile. The 2024 version was four feet tall when constructed. I will fill in the areas that have subsided and extend the perimeter fences to the height of six feet four inches. That particular height was not arbitrarily chosen, but dictated by my supply of 28” fence wire remnants from other projects.
This weekend, I verified that the aeration system is functional and collected readings from all the thermocouples to be sure they are reading properly. I discovered that two of the thermocouples were clearly malfunctioning, but the functional sensors were reading surprisingly high temperatures. Deep within the inner core, the temperature read as 150F – a value never before seen in my experiments! In other areas, temperatures vary from 110 to 140F.
I began repairs by digging out the two thermocouples that malfunctioned during the summer. As I dug deeper into the pile the heat of the uncovered strata could be felt through my gloves.
After reaching the necessary depth, I used a traditional bimetallic compost thermometer in an attempt to corroborate the readings obtained from the remaining thermocouples. This thermometer showed the outer core of the pile had temperatures as high as 138F, which accorded well with the electronic readings.
I suspect the reason for the thermocouple malfunctions is that, as the pile subsided, the wires were stretched past the point of breaking. In the image with the thermometer, you can see one of the thermocouple wires pulled downwards over a horizontal wire in the boundary fence.
Originally, the biomeiler was filled level with the tops of all perimeter fences. An insulating layer of dry wood shavings and sawdust was added above the entire top surface to a height of 6 inches at the outer edge and twelve inches in the center.
In the image, you can see that the surfaces of the inner and outer cores are now approximately four inches below the perimeter fences. The mantle surface is up to eight inches below the perimeter fence.
Now that the repairs have been made, I will begin making the upgrades.
The 2025 biomeiler project is underway!
I’m glad to read that you found two culprits (thermocouples not working properly) and the sinking pile of shavings and sawdust. Now to enjoy a winter of high functioning process!
Ever onward!