Koji is a living mix of mould and rice - and chefs can't get enough of it.SuppliedKoji is a miraculous living mix of mould and rice,sometimes soy or barley,that has been adopted by chefs to change the texture and flavour of food. From marinating wagyu to super tender chicken karage,koji is another tool in the chef's box of tricks.
What is it?
In Japan,koji is the building block of various foods and drinks,from sake to soy,mirin to miso. Steamed rice,barley or soybeans are mixed with a natural aspergillus mould which sends its tiny tendril-like hyphae to feed on the cooked grain. It produces enzymes that turn starch into sugar and proteins to amino acids – including glutamic acid,which gives us a sense of umami.
Why do we love it?
"Koji is pretty hot at present,"says chef Peter Gilmour for Quay in Sydney. He has used koji for over a decade since he imported spores from the US."I love the transformative powers that has to break down proteins in to the digestible and the delicious. I love the flavour of the way it works with different grains."Gilmour makes rice and barley koji in a three-day process. The black barley koji is used is dried,ground to a powder and mixed through an umami-rich stock,emulsified with butter,and served with noodles made with bone marrow."Koji is the superhero of Japanese flavours and culture,"says Central Victorian koji maker Yoko Nakazawa."There are some good chefs using koji in novel forms,as a flavour enhancer for bread and other things,"she says."But I love the way it can be mixed with salt and water and then fermented into the seasoning shio koji. Shio koji makes food taste more delicious and tender. It is the easiest way to use koji in the kitchen."
How do you use it?
You can make koji from scratch by buying the mould spores called koji kin online. You can also purchase pre-fermented rice koji from Japanese supermarkets. Take 300g of rice koji,mix it with 75g salt and 400ml of tepid water in a container to form a rough liquid. Cover and keep in a warm place for seven days until it becomes sweet,funky and milky. It is ready for use. (Alternatively,you can buy premade shio miso,but this has alcohol and preservatives and is not as complex.) Now you can use your shio koji to marinate chicken pieces with ginger,garlic,and soy sauce before rolling in corn starch and deep frying for sensational chicken karage. Use shio koji to marinate broccoli before sauteing to produce a rich-tasting veg with an almost cheesy flavour. Slice steak sized pieces of celeriac in shio koji before grilling on the BBQ. Marinate slices of topside beef with mirin and shoi koji to make super tasty pieces of beef to cook on the charcoal grill.
Where do you get it?
Buy koji spores online fromcookingwithkoji.wordpress.com or buy pre-fermented koji rice and soshi koji from Japanese foodstores and supermarkets.