On a recent trip to San Francisco I enjoyed a number of preparations involving koji at Bar Tartine. I also picked up some fresh koji and koji products from Mariko Grady at Aedan Fermented Foods, a wonderful resource which may be able to send some items mail order in cool weather; contact her through the website with inquiries. And, I picked up two tubs of commercial Cold Mountain koji for further experimentation.
Koji is rice that has been inoculated with aspergillus oryzae, a fermentation agent that turns the grains a snowy white. It is the base ingredient in making sake and amakazi as well as shio-koji, a salt marinade. The first thing I did with it was to make some koji bread, using the Cold Mountain base koji, following a recipe in the new Tartine 3 cookbook.
Bar Tartine chef Cortney Burns says this is the same recipe they use in the restaurant. It’s one of Chad Robertson’s new “porridge breads” in which adds a porridge made with a grain at 50% of flour volume; that porridge is typically 2 parts water and 1 part grain, simmered about 15 minutes till the liquid is absorbed and the grain becomes tender. It’s cooled, then folded into the dough after the second stretch-and-fold using the overall method in my Kettle Bread. I followed this recipe to make my koji bread but cooked at 15 degrees lower temperature because the sugar produced by the koji can cause the bread to burn if you’re not careful.
I tasted this bread fresh (shown above) and also as koji toast, which is how it’s served at the restaurant. I liked it but wasn’t overwhelmed by the result. The koji contributes a very mild sweetness-without-being-actually-sweet that reminds me of the effect of MSG, actually. But the texture and crumb is wonderful and Robertson says the porridge makes it last longer than regular bread, so there’s no reason I won’t continue to play with this recipe. (Next time I will ferment the koji before I use it, for one thing.)
I next made some vegetable pickles using the 385 marinade sold by Aedan Foods. (She also shares the recipe so you can make your own: 3 parts salt, 5 parts koji, 8 parts cooked rice, mixed then fermented for 7-10 days.) The method is to slice or chop vegetables such as carrots or cucumbers into serving-size pieces, mix the vegetables with a little salt and rub between your fingers to distribute the salt thoroughly, let it sit for 30 minutes until some liquid drains off, then wash and drain the vegetables. You then add marinade in the amount of ½ the weight of the vegetables and allow to cure overnight.
I did this with some daikon I had around, and also some broccoli. The results were, again, pleasing but mild. The “pickles” were more like vegetables in a salad dressing than something that had undergone a chemical transformation.
Later, I used Aedan’s shio-koji (a slurry made by adding water and salt to koji and fermenting a few days) as a marinade for salmon filets. The salmon was marinated overnight, then broiled. Yet again, the results were pleasant and mildly salty but not distinctive.
Have you tried koji cooking or eaten recipes prepared with koji? I’d love to know about your experiences since for now this trending ingredient is not knocking it out of the park for me. But I’ve got an awful lot of koji in the fridge, so my own experiments will definitely continue into the new year.