Added on by Josh Evans.

Researcher: Josh Evans
Start date: 28.6.13

It was only a matter of time, after working with koji for so long, that it would find its way to this.

Shio-koji (塩麹, lit. 'salt koji') is a mixture of koji, salt, and water. The salt kills the Aspergillus oryzae, while its enzymes remain; the salt and carbohydrates from the grain also likely create an ideal climate for some lactic acid bacteria (LAB) and perhaps some salt-tolerant yeasts to populate the mixture. It is a versatile ingredient, used to season, tenderise, and bring out the umami and sweetness of other foods.

There are many recipes out there, depending on region, family tradition and individual taste. We have settled on a rough ratio of

4 koji : 1 salt : 5 water
Mix together the ingredients, put into a container and cover with cheesecloth.
Let stand 10 days at room temperature, stirring every day.
Blend and/or pass through sieve if desired, then transfer to a jar and keep in refrigerator.

Rice koji tends to be white; since we mainly use pearl barley koji ours takes on a light brown colour. It has aromas of coconut and fruit and nuts.
For us it tends to yield both a firmer paste and a looser liquid – this may be because we use fresh koji instead of the dried variety more available at Japanese food stores, so our water content is higher. Though it can also be useful to have more solid and more liquid phases.

We have used it for a few things, some of which we will describe in upcoming posts.

In the meantime, if you have some leftover koji after starting some fermentations, don't let it go to waste – make some shio-koji instead.