White miso (Saikyo)

Saikyo miso — also called shiro-miso in its broader category sense — is the Kyoto regional style of white miso, distinguished by an unusually high koji-to-soybean ratio (typically 2:1 koji to beans by weight, sometimes higher), low salt (5-6%), and short fermentation (2-4 weeks rather than the months-to-years of darker miso). The result is pale ivory in color, sweet enough to use in desserts, with a delicate umami character and almost no funk.

The high koji ratio is the technical innovation that defines the style. Rice koji (Aspergillus oryzae grown on steamed rice) produces amylase enzymes that hydrolyze rice starch to glucose; in saikyo's formulation there is so much rice koji relative to soybeans that the resulting paste is genuinely sweet from undigested glucose alongside the umami compounds typical of miso. The short fermentation prevents the long-aging breakdown of those sugars into more complex (and darker, more savory) flavor compounds.

Saikyo's editorial position is distinctive: it's used as the marinade base for saikyozuke — fish (especially black cod, gindara) marinated 2-3 days in saikyo paste and then grilled — and in Kyoto-style miso-yaki preparations. It's not interchangeable with darker miso in dishes that benefit from saikyo's particular sweetness (saikyo dengaku, for example) but conversely it is too mild for dishes that need miso's depth (a saikyo-based miso soup is editorially pale-flavored compared to one made with red miso).

The regional naming is precise: 'Saikyo' (西京) literally means 'western capital' — Kyoto. The product is geographically protected in the same sense as Champagne or Parmigiano: a miso made outside Kyoto in this style is white miso, but cannot legally be sold as Saikyo miso. Major producers like Honda Miso Honten in Kyoto have continuous lineages dating to the 1830s.

Sandor Katz's framing of fermentation as a tradition embedded in geography applies here — the saikyo style developed in Kyoto's particular climate (humid summers, cool winters) and in service to Kyoto's particular cuisine (delicate, restrained, vegetable-focused). The product is inseparable from the region.