Summer Sourdough Crushed Ice & Water Temp Chart for a Hot 84 Degree (84°F / 29°C) Kitchen — Hand Mixing (75°F Target DDT)
4-factor Desired Dough Temperature (DDT) and 80 cal/g latent heat crushed-ice calculation for hitting 75°F dough in a hot 84°F room.
If you mix with 78°F tap water in a 84°F (28.9 Celsius) kitchen using hand mixing (75°f target ddt), the dough will land well above 75°F and ferment far too fast. The arithmetic 4 × 75°F − (84 + 84 + 84 + 2) gives the required 46°F (7.8°C) mix temperature instead. Your 78°F tap water is 32°F too warm for a 75°F dough, so 59g of crushed ice replaces that much of the 350g and 291g of tap water completes the mix.
- Required Water Temp
- 46°F (7.8°C)To hit 75°F DDT in 84°F room
- 350g Batch Ice Split
- 59g Ice / 291g WBased on 78°F tap water & 80 cal/g latent heat
- Mixer Friction Factor
- +2°FHand Mixing
- Target Final Dough Temp
- 75°F (23.9°C)Locks fermentation clock & protease rate
DDT Reference for 84°F Kitchens — Hand Mixing (75°F Target 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 |
|---|---|---|---|---|
| Batch 350g [Primary] | target 46°F / 7.8°C | ice 59g | liquid 291g | lands on 75°F |
| Batch 400g Small Mix | target 46°F / 7.8°C | ice 67g | liquid 333g | lands on 75°F |
| Batch 300g Standard Mix | target 46°F / 7.8°C | ice 51g | liquid 249g | lands on 75°F |
| Batch 500g Oversized Mix | target 46°F / 7.8°C | ice 84g | liquid 416g | lands on 75°F |
| Batch 250g Double Mix | target 46°F / 7.8°C | ice 42g | liquid 208g | lands on 75°F |
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Baking Sourdough in a Hot 84°F Room: Why You Need 46°F Water (59g Ice)
Latent heat of fusion is why the cooling arithmetic is not linear. Replacing 59g of the 350g of water with crushed ice removes not merely 59g × 1 cal/g of sensible heat, but 59g × 80 cal/g of phase-change heat, which is what allows a 28.9°C (84°F) room to be cooled into a 75°F dough.
A one-degree miss is cheap insurance, a five-degree miss is not. The difference between a 75°F dough and a 80°F dough is roughly a 20% change in fermentation rate, which is the difference between an open crumb and a collapsed one in a 84°F (28.9°C) kitchen.
Thermal Control Protocol for Hand Mixing (75°F Target DDT) in a 84°F Room
- Measure the Room First: Confirm the kitchen really is 84°F (28.9°C) with a thermometer on the counter, not on the window, because radiant sun can read several degrees warmer than the working surface.
- Temper Flour and Levain: Bring both to 84°F before mixing. Cold flour is the most common reason a 75°F target is missed in a 84°F (28.9°C) kitchen.
- Combine 59g Crushed Ice with 291g Tap Water: Mix the ice into the 78°F water first and let it chill completely before it touches the flour.
- Mix and Check: After hand mixing, probe the dough — it should read 75°F (±1°F) given the +2°F friction allowance.
Technical Q&A: Summer Sourdough Crushed Ice & Water Temp Chart
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 46°F target — but you must double the ice too, from 59g to 118g.
What water temperature should I use for sourdough in a 84°F kitchen with Hand Mixing?
Using Hand Mixing (+2°F friction) and targeting a 75°F final dough temperature, your theoretical water temperature is 46°F (7.8°C).
Does the type of mixer actually change the water temperature?
Yes, and that is exactly what the friction factor models. Hand Mixing (75°F Target DDT) contributes +2°F, so the same 84°F (28.9°C) kitchen needs a 46°F mix water for this machine and a different one for a hand-mixed dough.