What is the most reliable method to determine when a sugar syrup has reached the correct boiling degree?

Using a thermometer to test the temperature of sugar syrup is the most reliable method to determine when it has reached the correct boiling degree. Thermometers provide an accurate and objective measurement of temperature, which is crucial when making sugar syrups. Each type of sugar syrup (such as simple syrup, candy, or caramel) has a specific temperature at which it achieves the desired consistency and characteristics. Relying on a thermometer allows for precision, minimizing the risk of undercooking or overcooking the syrup.

Visual inspection, while occasionally useful for assessing certain stages of cooking, can be misleading, as color and texture may not adequately indicate the exact temperature. Flavor sampling may also not provide precise information about the syrup's structure or boiling point, as one might not be able to accurately assess the readiness. Checking the consistency after cooling can be useful for determining if the syrup has reached a desired stage, but waiting until it cools may lead to inconsistencies since the final texture can change during cooling. Therefore, using a thermometer is the most consistent and dependable method for achieving the correct boiling degree in sugar syrup.