With an excess of Giant Puffballs (Calvatia gigantea) around, we were thinking of a way to do something with them that can be stored for a longer time. Inspired by recent success in making miso paste from scratch, we decided to use the same procedure for fermenting puffballs. Initially the result was not quite like miso but after about two months the taste was getting quite similar to miso.
Miso paste (like many other fermented foods) is made using a fungus called Koji (Aspergillus oryzae). You can isolate Koji from store-bought vegetables if you feel like doing everything from scratch. Here we did not do that as it’s a tedious procedure that can easily fail. Luckily you can buy Koji rice which is rice inoculated with Koji. It is specifically made for fermenting foods and it can be bought from multiple sources.
The giant puffball happens to be one of the most easily identifiable mushrooms around. Just be sure to pick them when they are well over the size of a tennis ball and all white inside. This way they cannot be mistaken with dangerous mushrooms that sometimes grow out to a small egg size and can resemble a puffball. Another reason why you want puffballs to be all white inside is that they will produce spores at some point. This will be visible by browning inside the mushroom. When the mushroom is at this stage it can cause stomach upset.
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Puffballs often grow in grasslands sometimes forming circles of many mushrooms. The image above shows how the mushroom should look like when sliced in half.
Koji fermented giant puffball paste
Ingredients
- 200 grams Koji rice
- 200 grams Giant puffball
- 1/2 cup Water (Or about just enough to be able to blend the mushroom)
- 60 grams Salt
Instructions
- Cut the mushroom in half and inspect for any bad spots. Remove bad parts and the outer skin.
- Chop the mushroom in chunks.
- Put the mushroom with the salt in a blender. Add a bit of water and try to blend the mushroom pieces into a paste. If the mushroom pieces don't blend easily add water until they do. The result should look like a thick cream.
- Add the paste to a fermentation jar and add the koji rice.
- Let the paste ferment for about 2 months. Taste regularly if it is to your liking. If you are satisfied with the taste you can transfer the paste to the fridge for long-term storage. Before usage blend the paste or push the paste trough a sieve so you won't have any pieces of rice.
