Firstly, why do we need moulds to make tempeh?
Traditional tempeh is often produced in Indonesia using Hibiscus leaves (for tempeh starter production) or Banana leaves (for tempeh production). In western countries, sealed polyethylene pouch (=freezer bags) are more often used. Indeed, an appropriate packaging is important as it provides optimum oxygen supply, right level of humidity and temperature for inoculation and fermentation to occur during processing.
But we want to implement a reusable method to produce tempeh.