Let the hill do the work
The cellar was dug in 2015 into the north side of the ridge. At nine metres below the surface the earth holds a steady temperature all year. Our log, kept by hand since day one, shows the cellar between 16.5 and 17.5 degrees in every month.
Where we do need power
Fermentation creates heat. A tank of Chenin will warm itself past 30 degrees if left alone, and that would cook the fruit flavours. The press house therefore needs cooling for about eight weeks around each harvest.
Before 2023 that meant running a diesel generator for most of the harvest. Today a 120 kW solar array on the press house roof and a battery bank carry the load through every grid outage, and the generator runs only on grey August days.
What it cost and what it saves
The system cost about the same as four years of diesel at 2022 prices. It also stopped the noise and fumes beside the kitchen, which our guests noticed before we did.
Watching it all
Sensors in each tank and in the cellar report to the cellar team's phones through the COVORN apps, so Emeka knows within minutes if a tank warms up at night. The handwritten log carries on anyway. Some habits are worth keeping.
