Summer Sourdough Crushed Ice & Water Temp Chart for a Hot 78 Degree (78°F / 26°C) Kitchen — Hand Mixing (78°F Target DDT)
4-factor Desired Dough Temperature (DDT) and 80 cal/g latent heat crushed-ice calculation for hitting 78°F dough in a hot 78°F room.
Heat flows in two directions in a 25.6°C (25.6°C) kitchen: heat flows from the 25.6°C flour and levain into the dough, and hand mixing (78°f target ddt) adds +2°F of its own. To land the finished dough on 25.6°C, the 350g of liquid water must enter at 76°F (24.4°C). Because 74°F tap water is already cold enough for a 25.6°C dough, use the full 350g as liquid at 76°F.
- Required Water Temp
- 76°F (24.4°C)To hit 78°F DDT in 78°F room
- 350g Batch Ice Split
- 0g Ice / 350g WaterBased on 74°F tap water & 80 cal/g latent heat
- Mixer Friction Factor
- +2°FHand Mixing
- Target Final Dough Temp
- 78°F (25.6°C)Locks fermentation clock & protease rate
DDT Reference for 78°F Kitchens — Hand Mixing (78°F Target DDT) Water & Ice Split
The 2°F friction allowance for hand mixing (78°f target ddt) is already inside every target water temperature on this table.
| Recipe Water | Target Water Temp | Ice to Add | Water to Add (@ 74°F) | Dough Temp Achieved |
|---|---|---|---|---|
| Batch 350g [350g Ref] | target 76°F / 24.4°C | ice none | liquid 350g | lands on 78°F |
| Batch 300g 100g Lighter | target 76°F / 24.4°C | ice none | liquid 300g | lands on 78°F |
| Batch 400g 100g Heavier | target 76°F / 24.4°C | ice none | liquid 400g | lands on 78°F |
| Batch 250g Half Batch | target 76°F / 24.4°C | ice none | liquid 250g | lands on 78°F |
| Batch 500g Large Batch | target 76°F / 24.4°C | ice none | liquid 500g | lands on 78°F |
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Fine-tune starter hydration between 50% stiff and 125% liquid while keeping your desired dough temp (ddt) & ice solver ratios locked.
Baking Sourdough in a Hot 78°F Room: Why You Need 76°F Water (0g Ice)
Liquid water absorbs 1.0 cal/g per °C of warming, whereas solid ice at 0°C (32°F) absorbs 80 cal/g (144 BTU/lb) to melt into 0°C water before warming. That phase-change heat sink counteracts a 78°F (25.6°C) room plus +2°F of hand mixing (78°f target ddt) friction when the theoretical water temperature drops to 76°F.
Ice quantity and water quantity are not interchangeable views of the same thing. 0g of crushed ice is the solid portion; the 350g of tap water that accompanies it is what actually hydrates the flour. Both numbers must be weighed.
Thermal Control Protocol for Hand Mixing (78°F Target DDT) in a 78°F Room
- Account for the Friction First: Hand Mixing (25.6°C Target DDT) adds +2°F, so subtract it from your target before you calculate the water temperature — that single step is what distinguishes a 25.6°C dough from a warm one.
- Solve the 4-Factor Equation: 4 × 25.6°C − (78 + 78 + 78 + 2) = 76°F of mix water for this 25.6°C (25.6°C) room.
- Execute the Water Adjustment: Temper all 350g of water to 76°F (24.4°C) and skip the ice entirely.
- Probe the Finished Dough: The reading should be 25.6°C ± 1°F; anything else means one of the three probed ingredients was off.
Technical Q&A: Summer Sourdough Crushed Ice & Water Temp Chart
What happens if I use hot water from the kettle instead?
The dough lands above 78°F, the fermentation clock accelerates by roughly 4% per extra degree, and in a 25.6°C (78°F) kitchen the result is typically an over-fermented loaf that collapses in the oven.
How much colder is the water than the room in this 78°F (25.6 Celsius) kitchen?
2°F below the room temperature of 78°F. That gap is the entire thermal load that 2°F of hand mixing (78°f target ddt) friction and 78°F ingredients impose on the mix water.
Will the dough temperature change if I scale the recipe?
No. The 4-factor equation is a temperature balance, not a mass balance, so doubling the flour and water keeps the same 76°F target — but you must double the ice too, from 0g to 0g.