35°C = 95°F
🦠 Perfect for Sourdough Starter Cultivation
Peak wild yeast activity | 4-6 hour feeding cycle | Maximum fermentation power
Important: 35°C is for Starters, NOT Dough Fermentation
Use 35°C for: Building/feeding sourdough starters, cultivating wild yeast, levain preparation
DO NOT use 35°C for: Bulk fermentation of dough (too hot - causes rapid gas production, poor flavor, and over-proofing)
For bread dough fermentation, use 20-30°C (68-86°F). See 25°C guide.
Why 35°C is Perfect for Sourdough Starters
🦠 Wild Yeast Loves 35°C
- ✓ Optimal temperature: Wild yeast (Saccharomyces) thrives at 30-38°C
- ✓ Fast multiplication: Yeast doubles every 90-120 minutes at 35°C
- ✓ Strong activity: Peak CO₂ production for visible rise
- ✓ Reliable results: Consistent performance batch to batch
🧫 Lactobacilli Also Active
- ✓ Balanced growth: Both lactic acid bacteria and yeast thrive
- ✓ Moderate acidity: Develops tang without being overpowering
- ✓ Quick establishment: Starter becomes active in 3-5 days vs 7-10 at room temp
- ✓ Healthy ecosystem: Strong enough to outcompete bad bacteria
Sourdough Starter Timeline at 35°C (95°F)
| Day | What to Do | What to Expect | Activity Level |
|---|---|---|---|
| Day 1 | Mix 50g flour + 50g water. Keep at 35°C. | No visible activity. May smell slightly sweet. | ☆☆☆☆☆ |
| Day 2 | Discard half. Feed 50g flour + 50g water. | Few small bubbles. Slight alcohol smell possible. | ⭐☆☆☆☆ |
| Day 3 | Discard half. Feed 50g flour + 50g water. | More bubbles. May rise slightly. Developing sour smell. | ⭐⭐☆☆☆ |
| Day 4-5 | Feed twice daily (every 12h). Discard + feed 50g each. | Doubles in 4-6 hours! Bubbly, elastic. Passes float test. | ⭐⭐⭐⭐⭐ |
| Day 6+ | Maintain: Feed every 6-12h at 35°C, or daily at room temp. | Reliable, predictable rises. Pleasant sour aroma. | ⭐⭐⭐⭐⭐ |
💡 Pro Tip
At 35°C, starters become active 40-50% faster than at room temperature (25°C). Once established, you can maintain at cooler temps for slower feeding schedules.
How to Maintain 35°C (95°F) for Your Starter
Oven Light Method
Setup:
- Turn oven ON for 2 minutes, then OFF
- Turn on oven light only
- Place starter jar inside
- Check temp (should be 32-38°C)
Result: Usually 30-36°C - warm enough!
Seedling Heat Mat
Setup:
- Buy seedling heat mat (€10-20)
- Add thermostat controller (€15)
- Set to 35°C
- Place jar on mat
Result: Perfect 35°C ±1°C, set and forget!
Warm Water Bath
Setup:
- Fill large bowl with warm water (40°C)
- Place starter jar in water
- Cover with towel
- Replace water every 2-3 hours
Result: ~33-37°C, but needs monitoring
Instant Pot Yogurt Mode
Setup:
- Select "Yogurt" LOW setting
- Usually maintains 35-38°C
- Place jar inside (lid off Instant Pot!)
- Cover with cloth
Result: Perfect temp, but takes up counter space
Food Dehydrator
Setup:
- Remove dehydrator trays
- Set to 35°C if adjustable
- Place starter jar inside
- Leave door slightly open if too hot
Result: Very stable temperature
Router/Electronics Heat
Setup:
- Find warm electronic (router, modem, etc.)
- Place jar next to heat source
- Cover with box and towel
- Check temp with thermometer
Result: Free warmth! Usually 28-32°C
🌡️ Temperature Check
Always verify temperature with a thermometer! "Warm to touch" can be anywhere from 28-45°C. Above 40°C (104°F) risks killing beneficial bacteria.
Starter Maintenance: Temperature Guide
| Temperature | Use Case | Feeding Schedule | Best For |
|---|---|---|---|
| 4°C (39°F) | Long-term storage | Once per week | Infrequent bakers, vacation |
| 20-22°C (68-72°F) | Everyday maintenance | Once per day | Regular bakers, kitchen counter |
| 25°C (77°F) | Active maintenance | Every 12 hours | Frequent bakers, balanced activity |
| 35°C (95°F) ← BEST FOR BUILDING | Building from scratch, reviving neglected starter | Every 6-8 hours (2x/day) | New starters, quick activation |
💡 Strategy
Build at 35°C for fast establishment (Days 1-7), then maintain at 20-25°C on kitchen counter for convenience and slower feeding schedule.
Troubleshooting at 35°C
🚨 Too Much Liquid (Hooch)
Signs:
- • Dark liquid on top
- • Separated layers
- • Alcohol smell
Fix:
Pour off liquid. Feed more frequently (every 6h). Starter is hungry!
⚠️ Pink/Orange Streaks
Cause:
- • Bad bacteria taking over
- • Usually from contamination
- • Sometimes from too much warmth
Action:
DISCARD starter immediately. Start fresh. Sanitize all equipment.
✓ Perfect Activity!
Signs:
- • Doubles in 4-6 hours
- • Bubbly throughout
- • Pleasant sour smell
- • Passes float test
Next step:
Ready to bake! Or maintain at cooler temp (20-25°C) for daily feeding.
Frequently Asked Questions
What is 35°C in Fahrenheit for sourdough starters?
35 degrees Celsius equals 95 degrees Fahrenheit. This is the optimal temperature for building sourdough starters from scratch, as wild yeast thrives at this temperature and develops quickly (4-6 days vs 7-10 days at room temperature).
Can I use 35°C for bread dough fermentation?
No. 35°C is too warm for bread dough fermentation. It causes rapid gas production, poor flavor development, and risk of over-proofing. For bread dough, use 20-30°C (68-86°F). Reserve 35°C exclusively for feeding and building sourdough starters.
How long to feed sourdough starter at 35°C?
At 35°C (95°F), feed your sourdough starter every 6-8 hours (twice daily). The starter should double in size within 4-6 hours after feeding. If it doubles faster, increase feeding frequency.
Is 35°C too hot for sourdough starter?
No, 35°C is perfect for starters. Wild yeast and lactobacilli thrive at 30-38°C. However, above 40°C (104°F) risks killing beneficial bacteria. Always use a thermometer to verify temperature.
How to maintain 35°C for sourdough starter?
Best methods: (1) Oven with light on, (2) Seedling heat mat with thermostat, (3) Instant Pot yogurt mode (LOW), or (4) Food dehydrator set to 35°C. Always verify with a thermometer.
Related Fermentation Tools
🌡️ Other Fermentation Temperatures
- 4°C to Fahrenheit - Cold fermentation / starter storage
- 20°C to Fahrenheit - Cool kitchen fermentation
- 25°C to Fahrenheit - Room temperature proofing
- 30°C to Fahrenheit - Warm proofing box