I had a wonderful dinner at Bar Tartine in San Francisco last week. I knew they were doing things with koji and tried a steak tartare served on koji toast but there were so many flavors going on I couldn’t really focus on the koji.
Luckily there’s a recipe for koji bread in the new Tartine 3 cookebook which, says chef Cortney Burns, is the same recipe they use in the restaurant. This is 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 in after the second stretch-and-fold.
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. Cold Mountain brand koji is readily available at Japanese markets for around $7 for 20 ounces. I followed the porridge prep in a prerelease recipe from Tartine 3 and cooked 125g koji with 250g of water for what would eventually be 2 1k loaves; there’s a bit of magical math as Chad wants you to accept that 250 g water + 125 g grain is going to produce 250 g porridge. I got more like 360 g (allowing for some evaporation) and adjusted the other components accordingly.
The rest of the prep is sort of like the famous Tartine country bread, which I’ve made many times. For this loaf Chad specified a blend of hi-x and “strong white flour”; I used KAF Sir Lancelot. It’s baked at a slightly lower temperature than a regular loaf because of the sugar contributed by the koji.
The results are shown here. The loaves didn’t rise as much as I wanted due to the high moisture content, but I was happy with the crumb. You can almost see some rice grains if you look closely. The bread has a slightly sweet umami taste that’s very subtle, but pleasing.