A batch that went wrong, and what it taught me
The jar smelled like paint thinner and had a grey-black cap of mould. Here is what I did wrong, what I did next, and what I would do differently.
The batch was in a five-litre plastic jerry can on the kitchen shelf. I had put in the right weights — 150 g of palm sugar, 450 g of scraps (mostly pineapple crown, orange peel and a handful of apple cores), 1.5 litres of water. Twenty percent headspace. Screw cap. All correct on paper.
On day nine I opened the lid to burp it and got hit with a smell that was not the mild sweet-fermented smell you expect at that stage. It was sharp and solvent-like, and there was a grey-and-black patch about the size of a two-dollar coin floating on the surface.
What I did wrong
- I did not push the floating scraps down when I sealed the jar. The pineapple crown was sitting proud of the liquid line, and that dry, exposed surface is where the mould started.
- My scraps were too dry to begin with. I had left them on the counter for an afternoon while I got the sugar. That dehydration means less juice going into the ferment and a lower initial acidity, which makes the first week riskier.
- I opened it too late. The recipe says burp daily for the first two weeks and I had left it a full three days. Trapped CO2 can push liquid up and out around the seal, which then wets the underside of the lid and creates another mould-friendly surface.
What I did next
I discarded the batch. This is the boring, correct answer. Once you see grey or black mould on eco enzyme, the acidity has not established fast enough and you cannot reliably fish the mould out and continue — the mycelium is under the surface too. White film is a different story; grey-black is not.
I rinsed the container with hot water, no soap, and left it in direct sun for a day before restarting.
What I would do differently
- Cut the scraps smaller so they sink more readily.
- Weight the top with a smaller inverted plastic container to keep everything under the liquid line for the first week.
- Set a daily reminder to burp for the first fourteen days. This is the cheapest possible intervention and I skipped it out of confidence.
The second batch is on day forty as I write this. No film, faint sweet-alcoholic smell, floating pieces have sunk. It looks like every good batch I have ever had, which is to say: unglamorous.