Koji has three thousand years of history and an entire bibliography behind it. None of that is needed to use it this week.
In practice, starting with koji means starting with one product, in a dish you already know how to cook. The rest follows from curiosity, not study. This guide covers the first week — quantities, timings, and the mistakes worth avoiding.
Each of the three ferments solves a different problem in the kitchen. If you're starting with one, start with the Koji Extract — it changes the most dishes for the least learning.
Liquid shio koji. It tenderises meat and fish and deepens flavour without adding anything you'd notice. It's the marinade that makes Tuesday's chicken taste of something.
start hereA paste fermented for six months. It gives depth to stocks, sauces and butters — the flavour people credit to "it cooked for hours" when it was in fact one tablespoon.
for stocks and saucesSweetness that comes entirely from fermenting rice, with no added sugar. Drink it, or use it in place of sugar in smoothies and desserts.
for sweetening
Three uses, spaced out, each a few minutes of work. By the end of the week you'll have a feel for what each ferment does.
About one tablespoon per 250 g of meat. Rub it in, cover, and leave in the fridge for six hours — morning to dinner works well. Grill as you normally would, over slightly gentler heat: shio koji browns faster.
Don't salt before tasting. Shio koji already carries salt, and this is the most common first-time mistake.
Heat stock or water. Turn off the heat. Only then dissolve one tablespoon of miso per bowl, stirring until it disappears. Add whatever you have to hand — spring onion, tofu, mushrooms, cooked vegetables.
Miso must not boil: strong heat takes its aroma and its living cultures. It always goes in at the end.
Drink it plain and cold, to understand the flavour without anything in the way. Then try it in a smoothie, in place of sugar — start with half the sweetness you normally use and adjust.
Softened butter plus a teaspoon of miso, mixed. Over roast vegetables, pasta, toast, or a steak straight out of the pan. It's the best effort-to-result trick on this whole list.
The full recipes are on the site — and the jars are in the shop.