Final answer:
To lower the temperature of an ice/salt/water bath below 14 degrees Celsius, check the ratio of salt to water and ice temperature. Increase salt if necessary and add more ice. For significant cooling, consider dry ice or liquid nitrogen with caution.
Step-by-step explanation:
If the ice/salt/water bath is not reaching the desired temperature of 14 degrees Celsius or lower, there are several steps that can be taken. Making sure that you're using the correct ratio of one part salt to 11 parts water is essential, as specified in the instructions for an ideal ice cream maker's solution. Since the goal is to lower the freezing point of the water to create a cold enough environment for the ice cream mixture, you might want to increase the amount of salt slightly, as NaCl (table salt) lowers the freezing point when dissolved in water.
If increasing the salt does not achieve the target temperature, it could be that the initial temperature of the ice used is not cold enough. Recall that to heat ice from -15 °C to 0 °C and subsequently melt it, energy is needed. If the ice is not cold enough to start with, the bath may not reach temperatures as low as desired. In such cases, ensure you are using ice that is colder than 0 °C to begin with. Additionally, you might need to add more ice to the bath to achieve a colder mixture.
If the bath still doesn't cool down adequately, alternatives like dry ice or liquid nitrogen could be considered, but extreme caution must be used with these substances due to their much lower temperatures and associated risks.