Summer Sourdough Crushed Ice & Water Temp Chart for a Hot 90 Degree (90°F / 32°C) Kitchen — High-Friction Planetary Mixer (76°F DDT)
4-factor Desired Dough Temperature (DDT) and 80 cal/g latent heat crushed-ice calculation for hitting 76°F dough in a hot 90°F room.
Heat flows in two directions in a 90 degrees (32.2°C) kitchen: heat flows from the 90 degrees flour and levain into the dough, and high-friction planetary mixer (76°f ddt) adds +24°F of its own. To land the finished dough on 76°F, the 225g of liquid water must enter at 10°F (-12.2°C). Cooling from 78°F tap water down to 10°F means melting 125g of ice into the 350g batch and leaving 225g of liquid water; each gram of ice absorbs 80 cal on melting alone.
- Required Water Temp
- 10°F (-12.2°C)To hit 76°F DDT in 90°F room
- 350g Batch Ice Split
- 125g Ice / 225g WBased on 78°F tap water & 80 cal/g latent heat
- Mixer Friction Factor
- +24°FHigh-Friction Planetary Mixer
- Target Final Dough Temp
- 76°F (24.4°C)Locks fermentation clock & protease rate
DDT Reference for 90°F Kitchens — High-Friction Planetary Mixer (76°F DDT) Water & Ice Split
Calculated using 4-factor calorimetry and latent heat of fusion (144 BTU/lb / 80 cal/g) with 78°F tap water.
| Total Recipe Water | Theoretical Water Temp | Crushed Ice to Weigh | Tap Water (@ 78°F) | Resulting Final Dough Temp |
|---|---|---|---|---|
| [350g Ref]: 400g total water | mix at 10°F | substitute 143g ice | keep 257g warm water | friction +24°F absorbed |
| 100g Lighter: 350g total water | mix at 10°F | substitute 125g ice | keep 225g warm water | friction +24°F absorbed |
| 100g Heavier: 250g total water | mix at 10°F | substitute 89g ice | keep 161g warm water | friction +24°F absorbed |
| Half Batch: 500g total water | mix at 10°F | substitute 179g ice | keep 321g warm water | friction +24°F absorbed |
| Large Batch: 300g total water | mix at 10°F | substitute 107g ice | keep 193g warm water | friction +24°F absorbed |
Dynamic Stoichiometric Workbench (10°F (-12.2°C))
Test custom loaf weights or alternative fermentation schedules directly against the 125g Ice / 225g W benchmark above.
Baking Sourdough in a Hot 90°F Room: Why You Need 10°F Water (125g Ice)
The Desired Dough Temperature equation treats the dough as a single thermal mass with four contributions. For this 90°F (32.2°C) kitchen, three of them — room, flour and levain — are each 90°F, and the fourth is the +24°F that high-friction planetary mixer (76°f ddt) adds through shear. Solving for the water temperature is the only way to hit 76°F exactly.
A one-degree miss is cheap insurance, a five-degree miss is not. The difference between a 76°F dough and a 81°F dough is roughly a 20% change in fermentation rate, which is the difference between an open crumb and a collapsed one in a 90°F (32.2°C) kitchen.
Thermal Control Protocol for High-Friction Planetary Mixer (76°F DDT) in a 90°F Room
- Start the Night Before: In a 90°F (32.2 Celsius) kitchen the flour will sit near room temperature overnight if you store it sealed, so re-probe it in the morning rather than trusting yesterday's reading.
- Prepare the Water Station: Get the 10°F (-12.2°C) water ready before you open the flour bag — once the flour is wet the temperature negotiation is over.
- Blend Ice and Water: Stir 125g of crushed ice into 225g of 78°F tap water until the slush is uniform, then pour over the flour.
- Record and Repeat: Note the final probe reading alongside the 90°F (32.2 Celsius) room temperature so the next bake is a copy rather than a calculation.
Key Baker's Math Questions (Required Water Temp: 10°F (-12.2°C))
How accurate is the 10°F figure in practice?
Within about 1°F, provided the four inputs really are 90°F room, 90°F flour, 90°F levain and +24°F friction. Probe the finished dough to confirm and adjust your next bake.
Does the type of mixer actually change the water temperature?
Yes, and that is exactly what the friction factor models. High-Friction Planetary Mixer (76°F DDT) contributes +24°F, so the same 90°F (32.2°C) kitchen needs a 10°F mix water for this machine and a different one for a hand-mixed dough.
How much ice do I add to 350g of bread water in a 90°F room (High-Friction Planetary Mixer (76°F DDT))?
Replace 125g of water with finely crushed ice and use 225g of 78°F tap water to hit 76°F DDT.