Master Crumb

Kitchen Thermometer Guide for Sourdough Baking

Temperature controls nearly every aspect of bread making, from fermentation speed to knowing when your loaf is done. A good thermometer transforms guesswork into precision and helps you bake consistently every time.

Why Temperature Matters in Bread Making

Temperature affects:

  • Fermentation rate: Yeast and bacteria activity doubles roughly every 15F (8C)
  • Dough development: Warmer doughs develop faster but can over-ferment
  • Final dough temperature: Determines bulk fermentation timing
  • Doneness: Internal temperature confirms when bread is fully baked

Types of Thermometers

Instant-Read Digital Thermometer

The most versatile choice for bread bakers:

  • Reads temperature in 2-5 seconds
  • Works for water, dough, and finished bread
  • Thin probe minimizes damage to loaves
  • Price range: $15-100

Best for: Water temperature, dough temperature, checking if bread is done

Infrared (Non-Contact) Thermometer

Measures surface temperature without touching:

  • Instant readings
  • Perfect for checking Dutch oven temperature
  • Cannot measure internal temperatures
  • Price range: $15-50

Best for: Dutch oven surface, oven accuracy, baking stone temperature

Probe Thermometer with Cable

Stays in food while cooking:

  • Monitor temperature continuously
  • Often includes alarms
  • Cable allows oven door to close
  • Price range: $20-80

Best for: Monitoring bread during baking (advanced technique)

Oven Thermometer

Sits inside your oven to verify accuracy:

  • Many home ovens are off by 25-50F
  • Essential for calibrating your baking
  • Leave it in oven permanently
  • Price range: $5-20

Best for: Verifying oven temperature accuracy

Key Temperatures for Sourdough

Water Temperature

  • Cold water: 65-70F (18-21C) - slows fermentation
  • Room temperature: 75-80F (24-27C) - standard recipes
  • Warm water: 85-90F (29-32C) - speeds fermentation
  • Hot water: Above 95F (35C) - can harm yeast, use carefully

Final Dough Temperature (FDT)

Target: 75-78F (24-26C) for most sourdough

Calculate water temperature using:

  • Room temperature
  • Flour temperature
  • Starter temperature
  • Friction factor (from mixing)

Bulk Fermentation Environment

  • Cool (65-70F): 6-8+ hours bulk
  • Room temp (75-78F): 4-5 hours bulk
  • Warm (80-85F): 3-4 hours bulk

Cold Retard (Refrigerator)

  • Target: 38-40F (3-4C)
  • Slows fermentation dramatically
  • Develops flavor over 8-48 hours

Baked Bread Internal Temperature

  • Lean breads (sourdough): 205-210F (96-99C)
  • Enriched breads: 190-200F (88-93C)
  • Whole grain breads: 205-210F (96-99C)

How to Check Bread Doneness

Using an Instant-Read Thermometer

  1. Remove bread from oven
  2. Insert probe into center of loaf from bottom or side
  3. Avoid hitting the crust (which will be hotter)
  4. Wait for stable reading
  5. Target 205-210F for lean sourdough

Why Temperature Beats the Knock Test

The traditional hollow knock test is unreliable:

  • Subjective - sounds different to everyone
  • Under-baked bread can sound hollow
  • Does not account for density variations

Temperature is objective and repeatable.

Checking Your Oven Accuracy

Why This Matters

Most home ovens are inaccurate by 25-50F (14-28C). An oven that runs hot will:

  • Brown crust before interior is done
  • Burn bottoms
  • Create uneven bakes

How to Test

  1. Place oven thermometer in center of oven
  2. Preheat to 450F (230C)
  3. Wait 30 minutes after preheat signal
  4. Check thermometer reading
  5. Adjust your settings accordingly

Recommended Features

For Instant-Read Thermometers

  • Fast reading (under 3 seconds ideal)
  • Thin probe tip
  • Wide temperature range
  • Water-resistant
  • Auto-off to save battery

For Infrared Thermometers

  • Adjustable emissivity (for different surfaces)
  • Distance-to-spot ratio of 12:1 or better
  • Backlit display

Popular Models

Instant-Read

  • ThermoWorks Thermapen: Professional standard, fast and accurate ($80-100)
  • ThermoWorks ThermoPop: Budget-friendly, reliable ($35)
  • Lavatools Javelin: Good mid-range option ($25-30)

Infrared

  • Etekcity Lasergrip: Popular budget option ($15-20)
  • ThermoWorks Industrial IR: Professional grade ($60+)

Care and Accuracy

Calibration Check

Test your thermometer periodically:

  1. Fill glass with ice and water
  2. Stir and let sit 1 minute
  3. Insert probe - should read 32F (0C)
  4. Adjust or note offset if different

Maintenance

  • Clean probe after each use
  • Do not submerge electronics
  • Replace batteries when readings slow
  • Store in protective case