Q&A: What is frass?

Frass is the leftover from the production substrate. In other words you started with several ingredients like for example spent brewery grain and pig manure. And added larvae to that mix. After production you separate the larvae and the remaining ingredients are called frass. The frass is an ideal organic fertilizer.

It’s also important when you make your business plan to include the income from the frass. This can be a significant part in your turnover.

In Europe the law (at the moment of writing this article) states that the frass needs to be steamed (70 degrees) for 1 hour to be allowed to sell as organic fertilizer.

Perhaps in general, the steaming would not be needed but now as an EU grower you don’t have a choice.