Cold Pasteurising Mixture Recipes


There are three main recipes that I have used to successfully cold pasteurise straw.

Below are the recipes to make 10L of cold pasteurising liquid.

Make sure you use gloves and a dust mask when handling ingredients.


Recipe 1 – Hydrated lime

Agriculture Hydrated Lime. There are many different limes and it is important to choose the right one.

Make sure the Total Ca content is 90% or above. You may need to do a bit of ingredient reading.

Adelaide Brighton Hydrated Lime has an available lime index, expressed in terms of calcium hydroxide [Ca(OH)2]

 of 90% typically.

Magnesium will hinder mushroom growth so it is important to choose on that has less than 10% magnesium.

I use Adelaide Brighton Cement’s Hydrated Lime.

It does come in a 20kg bag so whenever I sell at a market or run a workshop I will give it to the customer for free. A 20kg bag will cost about $16

Use 100g (1/2 cup) of hydrated lime per 10L of water

Adelaide Brighton Cement – Hydrated Lime Information


Recipe 2 – Ash

Using sifted wood ash from a fire place is a great way to make a pasteurising mixture.This will greatly improve oyster mushroom yields.

Use 400g (2 cups) of sifted wood ash per 10L of water.


Recipe 3 – Laundry Powder


This has worked for me but I have only done it a couple of times. So for me it is not my preferred method.

Use 1 tablespoon of Laundry powder per 10L of water.


The fungi will use any soap as food and convert it to fungal tissue.  So there will be no soap residue in your mushrooms.

How to Cold Pasteurise Straw