When thickening a fruit filling with cornstarch or arrowroot, what is the key visual cue that tells you it has thickened properly?

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Multiple Choice

When thickening a fruit filling with cornstarch or arrowroot, what is the key visual cue that tells you it has thickened properly?

The thickening effect comes from the starch gelatinizing as you heat the filling. When cornstarch or arrowroot is cooked to its proper temperature, the mixture becomes glossy and translucent, thick enough to coat the back of a spoon. This clear, shiny nappe is the signal that the starch has gelatinized and the filling has thickened to the right consistency. Cooling or chilling won’t produce that same thick, clear texture, and simply adding more sugar won’t reliably thicken. So cooking until the filling looks clear and coats the spoon is the best cue.

The thickening effect comes from the starch gelatinizing as you heat the filling. When cornstarch or arrowroot is cooked to its proper temperature, the mixture becomes glossy and translucent, thick enough to coat the back of a spoon. This clear, shiny nappe is the signal that the starch has gelatinized and the filling has thickened to the right consistency. Cooling or chilling won’t produce that same thick, clear texture, and simply adding more sugar won’t reliably thicken. So cooking until the filling looks clear and coats the spoon is the best cue.

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