Background
Testing temperature variations and adding yogurt cultures to select for specific lactic acid bacteria, while evaluating how different koji substrates (rice, wheat, sorghum, oat, rye) cure soy curd to form cheese-like preparations.
Process
Treatments & Formulations
- Substrate Comparison (Shio Koji): Tofu cured in three shio koji bases (wheat, sorghum, rice).
- Direct Koji Cures (Overnight): Tofu cured directly with rice koji, oat koji, and rye koji.
- High-Temperature & Yogurt Culture Ferment:
- 50 g tofu per batch (150 g total across three samples)
- 10 g koji
- 2.5% salt
- Water to cover (~100 g)
- Small pinch (0.2 g) vegan yogurt starter
- Fermented at 105°F (40°C)
- Controls & Drying Formats:
- Smoked
- Dried (hot-dried vs. cold-dried)
- Parmesan-Style Blend (Fermented & Dried):
- 450 g tofu
- 50 g koji
- 2% salt
- 50 g lacto-ferment brine (from lacto-fermented wheat)
- Split treatment: Half fermented in the refrigerator wrapped in cheesecloth over a grate to dry; half fermented out of the refrigerator in a sealed container.
Notes and Observations
Initial Trial: 3-Day Renan Wheat Shio Koji Cure
After three days of curing in wheat shio koji, the tofu became completely soft, intensely sour, and quite salty. It is very flavorful, though overpowering when eaten on its own.
Compared to previous trials that yielded a profile that was quite cheesy, this batch is much more lactic and sour. This may be a result of the koji substrate used: rice koji tends to produce cheesier shio koji with a cheddar-like sharpness and funk, whereas wheat shio koji trends toward a sharper, acidic koji funk.
- Duration: A shorter cure (perhaps overnight) would likely yield a cheesier profile before acidity dominates.
- Alternative Method: Fermenting koji directly alongside the tofu (rather than using a prepared shio koji) might produce a much milder, less sour tofu cheese.
Substrate & Method Comparison Tasting Notes
- Rice Koji (Overnight): Pleasant light umami and subtle cheesiness. Worth testing with larger pieces of tofu.
- Rye Koji (Overnight): Oddly sour without much umami depth. An unusual profile.
- Oat Koji (Overnight): Good umami depth with a slightly unusual flavor—similar to rice koji, but less neutral.
- Rice Shio Koji (Fridge Marinated): Less cheesy, rounder profile with lower acidity. Pleasant and very similar to commercial/bento-style cured tofu (e.g., Aedan).
- Sorghum Shio Koji: Similar to rice shio koji, with a slight funk on the finish.
- Wheat Shio Koji: More flavorful with a slight cheesiness, but accompanied by a slightly plastic/funky note.
Interpretation of Findings
- The complete softening observed is consistent with continued proteolysis, although salt, acidity, and starting tofu structure also contribute.
- The hypothesis that a shorter cure tastes cheesier is reasonable as a sensory concept: it may preserve the koji’s mushroom, malty, and nutty top notes before salt, acid, and extensive proteolysis dominate.