Overview
Roasted onions are a high-flavor, flexible add-in for savory sourdoughs. Roasting concentrates sugars, reduces raw onion sharpness, and lowers free moisture when done correctly — all important for preserving dough structure and crumb. Use roasted onions in batards, boules, and sandwich loaves to add savory depth without excessive sogginess [1][2].
🛒 Recommended Products
We recommend the following tools for this recipe:
Digital Kitchen Scale
Essential for accurate baker's percentages and ingredient scaling
Dough Scraper/Bench Knife (OXO)
Helpful for folding and incorporating add-ins without overworking dough
Dutch Oven or Cast Iron Pot (CRUSTLOVE)
Provides consistent steam and high heat for oven spring when baking loaves with savory add-ins
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Why Roast Onions
Roasting transforms onion cell structure: heat breaks down pectin and converts starches to sugars, producing a sweeter, more aromatic ingredient that pairs well with sourdough's tang. The process also drives off some water and denatures enzymes that would otherwise continue to release moisture during fermentation, reducing risk of a gummy crumb [1][2].
Preparation Methods
- Best practices for preparing roasted onions for sourdough:
- Slice or dice uniformly to ensure even roasting. Thinner pieces caramelize faster and lose more moisture.
- Roast on a rimmed sheet at 200–220°C (400–425°F) until deeply browned and fragrant, turning once. High, dry heat encourages Maillard reactions and brighter flavor [1].
- For drier add-ins, roast longer or finish in a sauté pan to evaporate remaining moisture.
- Optionally toss with a small amount of neutral oil to speed browning; avoid sugars or high oil volumes that can coat flour and inhibit gluten development.
- Tools: Weigh ingredients on a Digital Kitchen Scale and roast on a sheet; transfer and mix with a dough scraper when incorporating [1][2].
Hydration & Dough Adaptations
- Roasted onions still contain moisture you must account for in your formula. As a rule of thumb, subtract roughly 5–10% of overall dough hydration when adding 15–25% roasted onions by weight; treat heavier inclusions as 'wet' add-ins and reduce water accordingly to keep the dough cohesive [1]. Consider these adjustments:
- Low inclusion (≤10% of flour weight): no hydration adjustment usually needed.
- Moderate inclusion (10–20%): reduce dough water by 2–5% of flour weight.
- High inclusion (>20%): reduce dough water by 5–10% or press extra roast/sauté moisture out of onions before use.
- Use a Digital Kitchen Scale to measure inclusions and calculate baker's percentages precisely [1][2].
How to Incorporate
- Gentle handling preserves oven spring and crumb structure:
- Add roasted onions after an initial bulk fermentation of 30–50% completion and incorporate using coil folds or slap-and-fold alternatives until evenly distributed. This reduces mechanical damage to onion pieces and avoids tearing the gluten network [1].
- Alternatively, bench-fold in the bowl with a dough scraper to fold inclusions in without overworking.
- Keep chunks relatively large (not pureed) when you want texture; smaller pieces mix more evenly but contribute more free moisture to the crumb [2].
Storage & Usage
Store roasted onions refrigerated up to 4–5 days or freeze in portioned blocks for longer. Thaw and drain any accumulated liquid before mixing into dough. For immediate use, pat on paper towel to remove excess oil or moisture — this step preserves dough handling and final crumb [1][2].
Recipe Ideas
- Simple starter ideas where roasted onions shine:
- Country loaf with 15% roasted onions and 5% grated hard cheese.
- Ciabatta-style freeform with 10% roasted onions folded late in bulk fermentation.
- Sandwich loaf: keep inclusion to ≤12% and press onions between paper towels to limit moisture for clean slicing. Bake in a Dutch Oven or Cast Iron Pot for high oven spring and crust control [1][2].