Baguette Batch: Warm Water and a Fast Ferment
A busy artisan bakery produces 240 baguettes each day from a direct dough made with 40 kg of 12.5% protein flour, 68% water, 2% salt and 0.4% instant yeast. The target dough temperature is 24°C. The schedule is 90 minutes bulk fermentation with one fold, then divide, shape and 45 minutes proof at 25°C. On Monday the flour is 22°C, the room is 26°C and the tap water is 29°C. The spiral mixer has a friction factor of 7°C. The baker mixes to a clear window, keeps the usual 90/45 schedule, and bakes at 240°C with steam. The loaves come out flat with pale crust, a dense crumb and a few large holes near the base. Tuesday, using 18°C water and the same flour and schedule, the baguettes are normal. The owner wants to know whether the flour or the method caused Monday’s loss and how to prevent a repeat without buying new equipment.
1. Calculate the water temperature that would have hit the 24°C target, and use the result to explain Monday’s dough temperature.
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Use the standard dough-temperature formula: water temperature = (3 × desired dough temperature) − flour temperature − room temperature − friction factor. With a 24°C target: (3 × 24) − 22 − 26 − 7 = 72 − 55 = 17°C. Monday’s 29°C water was 12°C warmer than needed, so the dough came out near 30°C. The flour is unlikely to be the cause because Tuesday’s batch with the same flour was normal. The mixer friction estimate should be checked, but the water temperature alone explains the gap. A probe reading of the final dough, not just the water, is the control point that was missed.
2. Explain how a 30°C dough produced the observed flat, pale, dense loaves even though the schedule was unchanged.
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At 30°C versus 24°C, fermentation is roughly 1.5–2 times faster, depending on the Q10 effect. The unchanged 90-minute bulk was effectively about 135–180 minutes at 24°C, and the 45-minute proof was similarly advanced. Overfermented dough loses gas retention: it spreads, has poor oven spring, and gives a dense crumb. The pale crust fits depletion of fermentable sugars, and the large holes near the base fit irregular degassing during shaping. This is not an under-mixing fault because the baker reached a clear window. The lesson is that time is not a control; dough temperature and dough condition are.
3. Give the practical correction for the next hot day, including at least two controls and one schedule change.
Read the worked answer
For the next hot day: calculate water at 17°C and use ice if the tap water is warmer; probe the final dough and record it. Shorten bulk fermentation to 60–70 minutes and proof to 30–35 minutes, judging by dough feel and the poke test rather than the clock. Move the dough to a cooler area if the room is above 26°C. Reduce yeast 10–20% only if the schedule cannot be shortened safely. Keep the flour specification unchanged unless repeated batches show a problem. Record flour, room and water temperatures for every batch so the correction can be repeated.