My first Bacchus fermentation trials are nearly finished. This year I experimented with oxygen levels in the juice from the press.
There were two variables:
1. Juice pressed hyper-reductively in an environment with < 1 % oxygen
2. Juice saturated with oxygen
Both were fermented in duplicate in 17 litre stainless steel kegs at 15 °C using the same yeast strain. It was really interesting to see how they behaved during fermentation. The oxidised juice fermented so much more quickly.
Next step is to rack them and send them for GC/MS (Gas Chromatography / Mass Spectroscopy) analysis to see how the aromas have been influenced.
I’m pleased that they seem to have worked as it can be tricky to complete small-scale fermentations without oxidation or other problems.
I had hoped to measure the exact amount of oxygen I was adding to the juice but this proved very tricky. I’ve been speaking to a number of researchers in South Africa and New Zealand and have a plan for next year as to how to do this better.