Adding herbs to your shio koji is a simple way to boost its flavor and preserve your fresh herbs simultaneously. Seriously, I have a little bit of shiso shio koji left from last year and it still tastes as strongly as it did 6 months ago!
Some folks seemed surprised and inspired by my basil shio koji post on instagram/twitter. It’s so simple and seems so obvious that I hesitated to post it as a “recipe”, but a few internet searches revealed no results! And so, I present:
Herbed Shio Koji
- 1 part koji rice
- 1 part spring water
- 15-30% (roughly) fragrant herbs (basil, perilla/shiso, tarragon, mint, etc.)
- 5-10% salt (non-iodized)
- Break up the koji rice. If you have a food processor, use that to maximize surface area. Weigh it and prepare the same amount in weight of water.
- Mix together the koji rice, water, and herbs in a bowl. The amount of herbs you add is up to you, 15-30% the weight of the koji+water is a rough guideline. You can chop the herbs if you’d like, the whole thing will get blended smooth eventually.
- Calculate 10% of the total weight and add that amount of salt to the mix. A finer salt (like “pickling salt”) works well for this, but kosher salt would be ok too.
- Pack the mixture into a clean mason jar or other glass container with a loose-fitting lid. You’ll want a little bit of headspace, roughly an inch or so, because it can expand as it ferments. Don’t forget to add a label with the date!
- Let the jar sit on your counter for at least 1 month. For the first week, mix it well once per day, then at least once per week until it’s ready. This will be difficult in the beginning, because the rice will completely soak up the water, but it will break down eventually.
- After a month, it the rice should have broken down enough that stirring is easy. Blend it smooth.
Kept in the fridge, it should last several months, potentially a year or more. Use it to marinate meat, add to steamed or charred vegetables, or use it as an herby, sweet, umami-enhancing condiment.