📝 About This Recipe
A cornerstone of West Javanese culinary heritage, Oncom is a unique fermented delicacy that transforms humble legume by-products into a savory, nutty masterpiece. Unlike its cousin Tempeh, Oncom utilizes Neurospora intermedia mold, which imparts a vibrant orange hue and a complex, earthy aroma reminiscent of roasted nuts and fine mushrooms. This recipe guides you through the traditional process of creating 'Oncom Merah' from scratch, resulting in a versatile protein that is deeply satisfying and rich in history.
🥗 Ingredients
The Base Legume Mixture
- 500 grams Soybean pulp (Okara) (freshly squeezed from soy milk production, squeezed dry)
- 250 grams Peanut press cake (Bungkil Kacang Tanah) (or roasted peanuts ground into a coarse, dry meal)
- 2 tablespoons Rice flour (to help manage moisture levels)
The Culture (Inoculant)
- 1 teaspoon Oncom Starter (Ragi Oncom) (containing Neurospora intermedia spores)
- 1 tablespoon Rice flour (for starter mix) (to act as a carrier for the spores)
Acidification & Prep
- 1 tablespoon White vinegar or Lemon juice (to lower pH and prevent spoilage)
- 2 liters Filtered water (for soaking and steaming)
- 4-6 large pieces Banana leaves (cleaned and softened over a flame for wrapping)
👨🍳 Instructions
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1
Begin by thoroughly pressing the soybean pulp (okara) in a cheesecloth to remove as much moisture as possible; it should feel crumbly, not soggy.
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2
If using whole peanuts, roast them lightly and grind them into a coarse meal, then mix them thoroughly with the dry okara in a large mixing bowl.
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3
Prepare a steamer over medium-high heat. Place the legume mixture into the steamer basket lined with a thin cloth and steam for 30-40 minutes to kill unwanted bacteria and soften the fibers.
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4
Spread the steamed mixture onto a clean, flat bamboo tray (tampah) or a baking sheet lined with parchment paper.
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5
Allow the mixture to cool until it reaches 30°C (86°F). This is critical; if it is too hot, the spores will die; if too cold, fermentation will be sluggish.
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6
While cooling, sprinkle the vinegar over the mixture and toss lightly to distribute. This creates an acidic environment that favors the Oncom mold.
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7
Mix the Oncom starter (ragi) with 1 tablespoon of rice flour in a small bowl to ensure even distribution.
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8
Sieve the starter mixture evenly over the cooled legumes, then use clean hands to mix thoroughly for at least 2 minutes.
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9
Pack the mixture into wooden molds or wrap them tightly in softened banana leaves, forming rectangular blocks about 2-3 cm thick.
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10
Pierce the banana leaf casing with a toothpick every 2 cm to allow the mold to breathe; oxygen is essential for Neurospora growth.
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11
Place the blocks in a dark, draft-free area with a consistent temperature of 25-30°C (77-86°F).
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12
After 24 hours, you should see white fuzzy growth. By 36-48 hours, the mold should turn a characteristic bright orange or salmon color.
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13
Once the block is firm and completely covered in orange spores, the fermentation is complete. Remove from the wrap and store in the refrigerator.
💡 Chef's Tips
Moisture control is the most common pitfall; if the mixture is too wet, it will rot rather than ferment. Always use sterilized equipment to prevent the growth of harmful bacteria like Aspergillus flavus. If you cannot find 'Ragi Oncom' locally, specialized fermentation suppliers online carry Neurospora intermedia cultures. The fragrance should be pleasant and nutty; if you detect a strong ammonia or foul smell, discard the batch. For a denser texture, place a light weight on top of the blocks during the first 12 hours of fermentation.
🍽️ Serving Suggestions
Slice into rectangles, marinate in garlic and coriander, and deep-fry until crispy (Oncom Goreng). Crumble into a spicy stir-fry with bird's eye chilies and Thai basil (Ulukutek Leunca). Grill over charcoal and serve with a spicy peanut dipping sauce for a smoky appetizer. Use as a savory filling for 'Comro' (fried cassava fritters). Pair with steamed jasmine rice and a side of fresh sambal terasi.