Your first batch

Making eco enzyme is genuinely simple. You mix three ingredients in the right proportions, put a lid on the jar, and wait three months. The waiting is the hardest part. Everything else on this page is small refinements that make the wait more likely to end in something useful.

This guide assumes you have never done it before. If you already have a batch on the go, skip ahead to reading your batch.

• A plastic container with a screw lid, between 1.5 and 5 litres. Bigger is fine, smaller is fiddly.
• A kitchen scale that can weigh in grams.
• Brown sugar: palm sugar, molasses, jaggery, gula merah or raw cane. Not white refined sugar.
• Fruit and vegetable scraps: peels, cores, tops and tails from raw produce.
• Water: rain, filtered, or tap left uncovered overnight so the chlorine can leave.

One part sugar, three parts scraps, ten parts water, by weight. So for every 100 g of sugar you use 300 g of scraps and 1,000 g (one litre) of water. Scale it to whatever container you have. Weigh, do not estimate — the microbes are not forgiving of rough guesses in the first weeks.

Only fill the container to about eighty percent. You need headspace for the gas the fermentation will produce.

1. 1

   Weigh the water

   Put your empty container on the scale, tare it, and pour in the water. Note the weight. Everything else is calculated from this number.

   tip — One litre of water weighs one kilogram. Metric makes this easy.

2. 2

   Dissolve the sugar

   Take a small amount of the water into a separate bowl and stir the sugar in until it dissolves. Pour it back into the container. This just makes life easier for the microbes at the start.

3. 3

   Add the scraps

   Chop scraps into pieces roughly the size of a walnut. Add them to the container. They will float; that is normal.

4. 4

   Seal the lid

   Close the container firmly. It should be airtight enough to keep fruit flies out and loose enough that you can open it easily to release gas.

5. 5

   Label it

   Write the date on the outside with a marker. In three months you will want to know exactly when it started.

Open the lid once a day for the first fortnight to release the gas. You will hear a hiss and smell something sweet and yeasty. This is the point where most people worry they have done something wrong. You almost certainly have not.

After the first two weeks, once a week is enough. On day thirty, stir the batch with a wooden or plastic spoon to push the floating scraps back under the liquid, then close it and leave it alone.

The liquid should be a clear amber colour and smell sour, sweet and slightly vinegary. Strain it through a cloth, bottle it, and it will keep almost indefinitely. What to do with the leftover pulp and how to filter properly is covered in harvest and filter.