GIFSQ Tools · Module 17 — Food Processing, Thermal Engineering & Utilities · Tool 325 of 500
Analyse a cooling curve with Newton’s law of cooling: the product temperature at any time, the cooling half-time, and the time to reach a target temperature.
Try sample values — fills the form with the worked example below.
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Temp at time (°C)
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Cooling half-time (min)
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Time to target (min)
Equation: T(t) = Te + (T₀ − Te) × e^( −k t); half-time = ln 2 ÷ k; time to target = ln((T₀ − Te) / (Ttarget − Te)) ÷ k.
Method: Newton’s law of cooling, the standard first-order cooling model used in food process engineering (Heldman and Singh, Food Process Engineering).
Assumptions: the cooling medium temperature stays constant; a single rate constant k describes the whole cooling period; no internal temperature gradients are modelled.
Limitations: real products cool in two stages (surface then centre) and k changes with agitation and product size; fit k to measured data for the product and vessel.
Rounding: temperatures and times to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Newton’s law of cooling, the standard first-order cooling model used in food process engineering (Heldman and Singh, Food Process Engineering).
Assumptions: the cooling medium temperature stays constant; a single rate constant k describes the whole cooling period; no internal temperature gradients are modelled.
Limitations: real products cool in two stages (surface then centre) and k changes with agitation and product size; fit k to measured data for the product and vessel.
Rounding: temperatures and times to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Cooling from 90 °C in a 20 °C medium with k = 0.05 per min: after 30 min the product is 35.62 °C, half-time 13.86 min, time to 25 °C 52.78 min.
Enter values above to see results.
Cool cooked foods through the danger zone quickly: the time between 60 °C and 10 °C is the figure your food safety plan cares about. Tool 325 of 500 — GIFSQ
